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Fender Hot Rod Deluxe Amp Repair Video Part 2
By Gary | March 21, 2008
In this amp repair video, I'm showing how to clean the pots. Just a little spray into each (small opening in the pot casing) and then work the knob.
I WOULD RECOMMEND TURNING OFF THE AMP AND UNPLUGGING FROM THE WALL FIRST.
Clean the jacks also and make sure they are nice and tight to the feel. By that I mean plug in and out the guitar chord to make sure there is a tight grip. If not, I recommend changing the plug which will require solder/unsolder chops on these units. Notice the soldering video, I will cover unsoldering in another video.
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Topics: amp repair (Fender) | 99 Comments »
July 14th, 2008 at 1:55 am
Hi Gary,
I just bought a Fender Twin off some guy. It hums loud even while not playing and makes a huge clashing sound as if a symbol is being hit. Can’t find info on the clashing sound anywhere. Seems to happen more when the amp moves. It is in casters.
Thanks,
Tom M
Las Vegas
July 14th, 2008 at 2:00 am
Hello,
Sounds like your reverb pan in the bottom is plugged in backwards…the two silver RCA plug cords on the back panel, try unplugging, notice where they are,,write it down if you need to…switch them… hopefully amp works correctly now…
other than that, you have problems,,,
some twins the reverb line cords could be grey, one I believe will have a red ending…also make sure they are plugged into the reverb send/receive jacks,,
Gary
July 19th, 2008 at 2:02 pm
you were absolutely right. I fixed it. Now I here a buzz though very loud with nothing plugged in, any ideas?
Tom
July 19th, 2008 at 2:10 pm
On the amp, are you saying, now it works but you have buzz…with nothing plugged in?
Is the buzz too loud to deal with or is it tolerable?
Could be the wiring of the room you are in
Could be the amp is not grounded correctly, see if there is still 3 prongs on the AC cord,,if there is great,,switch the ground on the switch on the back..
If it still buzzes too loud, you may have real problems…could be someone went into it trying to figure it out and didn’t hook it up right when they put it back together, thus the reverb wires were backwards….make sure it is not your guitar or guitar cord causing the hum.
can’t think of anything else right now, other than take it to another building and try it.
Gary
August 21st, 2008 at 9:09 am
hi,Gary…thx a lot for the video..i love it…thx!! btw, i just want to ask your advice for my amp’s problem : the volume is decreasing suddenly in both channel: clean and lead channel and it always synchronized…(if my clean channel volume is decreasing, the lead channel is also decreasing,..visa versa..) it sounds like that there is a sound that want to goes out but it can’t … this problem came in no precise time and paroxysm…sometimes in the middle of my playing and sometimes it already came just as i start turning on the amp volume…
i have tried to isolate the problem by using my amp’s “return” to know if the damage is on the preamp or power amp, but i think the power amp is still ok..(the “master” volume is still in perfect condition and no volume decreasing there)….
i also use another guitar and cable or even using another amp to find if the problem is on my guitar or cable but i found that my guitar and the cable are just fine…i also always keep my amp away from the wall to keep a proper ventilation for my amp..
and then, yesterday, i found that i can have the volume back to normal if i turn the volume knob to the maximum position or strum really hard to the strings of my guitar…so as an example: if i have my volume decreasing in some position(x position), then i can fix it if i turn the volume knob to maximum position and the amp volume is back to normal…(if i turn the knob to x position again, the volume produced by my amp is normal for the x position again) ……but then i found also that it won’t stay long, the problem will come again and again…
what happened with my amp?
August 21st, 2008 at 9:13 am
oh ya, some people suggest me to clean the input and the pots with the contact cleaner..but how should i apply the contact cleaner to the input?in your video, i realize that u are applying the contact cleaner by spraying the jack..but some website, told me to spray the input socket n jiggling it with the jack..is it ok to do that?
and also, should i always open my amp’s case for cleaning the pots like you do in that video?
thx u
September 2nd, 2008 at 5:02 pm
Hello,
Sorry I missed your questions. I “sounds” like you have a loose component in the preamp section somewhere. On those units it could be near the tube, like say a resistor that feeds the plate voltage on an input tube. They are famous for pulling away from the circuit board over time because of heat. Could be anything really. I’m not sure where you are on the tech chops. Finding the problem may not be that hard, getting the board out to resolder the component correctly takes a bit of skill.
On the pots, it doesn’t hurt to spray into the shaft, I just spray the jack and then work the jack back and forth to scrape/clean the connections. Also use top of the line cleaner especially for this type of work.
Gary
November 20th, 2008 at 11:20 pm
Hi Gary
Was watching your video on How To Clean The Pots on a Fender Amplifier. I have a 1980 Fender Twin Reverb amp.
All the knobs are really noisy/ scratchy as it has not been played in about 10 Years.
Where can I purchase ” Funk Out Cleaner ” ??
Can not find any reference regarding this product on-line .
Is there another equivilant more common cleaner you would recommend ?
Thanks
Gerry
UPDATE: This is a Peavey product,most Peavey dealers carry it or can get it. I should say it’s a Caig product but I don’t know which one. I get as funk out from Peavey.
February 9th, 2009 at 11:31 am
hello Gary, how are you?, thanks for the video it’s very informative.
I have a Fender Hot Rod Deville 212 amp that had a problem with the treble knob and the c48 .47uf 63v capacitor in the foot switch area of the board, this was replaced and the foot pedal appears to work normally again (OD boost light was dim, not any more)(can’t tell if the treble knob is fixed). Lol, now the amp has no clean channel sound at all and distortion only comes in if you put the drive and master volume all the way up, which results in a rather low (compared to usual) buzzing, chattering distortion sound.
I’ve checked the soldering and the tubes “appear’ to be okay, one of the pre amp tubes looks a little dimmer than the rest, but thats about it, they all still light up.
If you could send any helpful information my way I would really appreciate it, I already have the schematics and wiring diagams.
Thanks a lot,
Daniel
February 9th, 2009 at 2:37 pm
Hello,
From what I understand of your problem, – you had a treble pot problem and footswitch problem, got it repaired and now it doesn’t work right?
If your channel problem occurred upon getting your amp back then I would take it back to where ever and tell them you have new problems since the repair.
If this is not the case then I would check the channel switching circuitry first, which is going to be some FET’s…best thing to do with FET’s is just replace them, don’t try to trouble shoot them..there like a buck a piece and your time is more important if you suspect them…
This is a start.
Gary
February 15th, 2009 at 12:50 pm
thanks,
Unfortunately I cannot get ahold of the guy who replaced the treble pot and the capacitor, I noticed that the same type of capacitor (.47uF 63v) is in spot C17 on the board and was loose, I replaced the solder, but it made no difference to the sound. I already spent too much trying to get it fixed the first time, so I’ll have to do the repairs myself this time. I am an Electrician by trade (residential/commercial, building), but have some board/soldering skills. Are the capacitors in C17 and C48 actually capacitors or something different?, I notice offer “C” designated spots are positive and negative and that the type that I had replaced is not, also it looks more like a little two pronged tooth rather than the others which are cylindrical. Sorry if I’m asking uneducated questions, but no one else seems to want to help.
If the treble pot wasn’t replaced correctly would that have the same effect as no clean channel at hearable levels or the distortion being low and static filled at full volume?. I’ll start diagnosing the voltage/tolerances and what not, I guess without a diffinitive problem or by not knowing if the “tech” (used loosely) fixed it in the first place I’m kind of up the proverbial creek.
Sorry for writhing so much and giving you any headaches,
Thanks a lot for your help,
Daniel
February 21st, 2009 at 4:09 am
Hi Gary,
Thanks for the informative video! I just bought an amp (Crate TD-50C, hybrid tube pre-amp, solid state amp) used off a guy. It worked great when I first bought it, but in about a week, it stopped putting out sound after about 4 strums of the strings and stopped recognizing the Channel A/B switch. I realize your videos focus on Fender amps, but I’m wondering if you have any insights as to why my amp will draw power just fine and recognize the chorus switch (even if no sound comes out) without putting out any sound from guitar? I’ve also hooked it up to my drum kit with no luck there, either, so I really don’t think it’s the guitar or the cord.
Thanks in advance for any thoughts,
Jason
February 21st, 2009 at 4:28 am
Hello,
It’s a little hard over the net to pick up on your repair. Getting an amp back from a tech or whomever and it not being repaired correctly presents 2 problems. You have to fix what he did and you have to repair the original problem.
You’re going to need a service schematic so you can look up part numbers, ratings, and also it will have the component layout so you can make sure parts have the correct polarity, such as caps.
Of course if you could a/b against another unit it would save a lot of time but other than that you need the schematic. Fender usually had them with the amps in the newer units.
I can’t imagine a tech putting in the wrong pot or in wrong, in these units it’s pretty straight forward, I would say you going to have a component in wrong, or the wrong component, or a trace not making connection because it was butchered somehow.
I would start off eyeballing everything on the board, follow it on your schematic using your ohm meter..like I said over the net this one would be a hard nut to crack.
Gary
February 21st, 2009 at 4:36 am
Hello Jason,
You must have popped in while I was answering above.
Maybe I need to put up a forum for answers. I don’t really understand what you’re asking. Are you saying you can hear the chorus making it’s swirling noise but you can’t hear the guitar coming out of the amp?
If so, then your losing your signal at the front end.
If it’s has a send/receive plug your guitar straight into the receive jack and you should hear it quietly, that will verify it’s the front end or not.
If I got your question wrong let me know.
Gary
March 4th, 2009 at 2:48 am
Gary, thanks for the quick response. Oddly enough, the solution turned out to be disturbingly simple. Crate’s online support wrote back (they were running 2 weeks behind in responses, they said) and mentioned that if the amp didn’t receive regular use, the jacks could oxidize. I sprayed the end of a q-tip with WD-40, swabbed the inside of the jacks and presto, crisp, clean sound. Thanks again for taking the time to answer the question.
March 4th, 2009 at 3:21 am
Hello Jason,
Well it was an easy front end but I must tell you, do not use WD-40 on your amp from now on. You didn’t really hurt anything. I hope the Crate tech didn’t tell you to use that. It leaves a residue that is just plain messy, even the cheapest tuner cleaner at Radio Shack is better. So at a later date if it’s starts cutting out again you may need to go in and clean the WD-40 out with a real good electrical cleaner spray like Funk Out by Peavey which is a Caig Product.
Cheers,
April 4th, 2009 at 4:47 pm
Hello there.
I have encountered a problem with my fender hot rod deluxe amplifier. This problem only concerns the drive channel, the clean channel is not being affected. When the bass knob is turned to 4 or higher a low buzz occurs. This buzz decreases in frequency as the knob is turned higher but gets higher in pitch. Whilst buzzing, if the drive knob is turned down, the buzz gets louder. If the gain is turned up, the buzz gets more frequent and oscillates to a squeaky pitch. The problem is present even if a jack plug is not in.
many thanks
Gus
April 4th, 2009 at 5:51 pm
Hello,
That’s a little strange to diagnose over the net. Make sure it’s not something simple like a bad jack.
By that I mean it’s not shorting to ground. Like the effects loop or even the input jack not making a good connection to the guitar cord or to ground when it’s not being used.
That’s a real shot in the dark answer since it’s only in one channel (at this point) other than that it may be a component like a cap on one of the tube circuits in the drive section or in the supply itself, common to all circuits but showing up in the high gain section first…again this one is a little rough to diagnose just typing.
You could try switching the drive tube out with the tube next to it to see if the problem goes away or moves to another circuit.
Hope this helps.
Gary
April 4th, 2009 at 7:56 pm
hi thanks for the quick reply.
I have swapped the two preamp valves and the problem hasn’t changed. All jack leads are out of the amp, so there is no jack lead going to the inputs or effects loop.
it looks like I’m gonna have take it to a shop
many thanks for your help.
April 4th, 2009 at 7:59 pm
woah, just switched it back on at there was a faint crackle. even on the clean channel.
April 4th, 2009 at 9:05 pm
Hello,
Hmmm, probably a power supply problem or something in the output section, the suspicious hum that started to be noticed in the high gain section.
Unless of course you mean the amp is working now with just a faint crackle but I don’t think that is what you mean.
If you’re not up on repair chops I would take this to a tech that knows what he/she is doing.
Gary
April 5th, 2009 at 12:16 pm
hey there. sorry to keep bothering you all the time. i understand that my explanations are not brilliant so i made a video outlining the problem.
thanks again
http://www.youtube.com/watch?v=EquzqRmBj8g
April 5th, 2009 at 5:56 pm
Hello Gus,
Hey no bother, interesting video. I’m going to have to think on this one a bit, I’ve seen it before.
First off, usually when I get something like this in someone has been playing with the circuit recently.
If that’s not the case, you got a cap breaking down someplace is what I would suspect, either a coupling cap or some type filtering cap on a circuit or in the supply. Which sums up the role of caps.
It’s a little hard to trouble shoot this one over the internet. If it’s not common to both channels then it’s going to be a little shot in the dark to isolate it.
Gary
April 17th, 2009 at 10:53 pm
Hi,
I am torn between buying a hot rod deluxe or a hot rod deluxe bluesman. From what I can see the speaker Celestian Vintage 30 and the knobs colour is the only difference.
However I cant find any review or comparrison with the hot rod deluxe. Can anybody advise. PS I use a 175t gibson, Strat 93. Like the jazz clean tone, with the addition of a full tone pedel for overdrive. Thanks.
April 18th, 2009 at 2:12 am
Hello,
Can’t help you there, usually musician’s friend has decent reviews.
Gary
April 29th, 2009 at 11:13 am
Hey man! Top video! You can almost charge money for this kinda thing!! Great idea!
SO!
I’m borrowing my friends Fender Hotrod Deluxe…
I’m in trouble… It worked fine one second…
then one time turn it on, and I got no red light… no sound, no nothing!!
I tried changing the fuse… nothing…
I’ve tried different power sources.. nothing.
God help me, I’ve even tried jiggling the power supply cord !!!!
(obviously I’m just another mindless muso, lost in the world of sound and art and ignorant to everything else.)
Should I take it in to get repaired? And risk being charged a fortune cause I don’t know anything about it???
Please save me wise man gary!!
April 29th, 2009 at 12:31 pm
Hello,
2 things, you sure the fuse you put in was good? Are you sure you’re plugged into a hot wall socket?
Since you don’t know much about amps, there’s not much I can suggest. Do you know one of the people at the music store that can look at it real quick. Usually when it’s working one minute and then you turn it on and nothing works it’s going to be something simple. I say usually, anything is possible but chances are it’s not that bad of a repair job. Are you sure the bulb is not blown and the tubes are warming up and it just looks dead?
Take it to another wall socket where something plugged into it is working to verify the socket is hot.
Hope this helps and tell you’re fiend what happened.
Gary
May 26th, 2009 at 1:42 am
Gary,
I have the same Amp as Jason, the Crate TD-50C, and you mentioned, “If so, then your losing your signal at the front end. If it’s has a send/receive plug your guitar straight into the receive jack and you should hear it quietly, that will verify it’s the front end or not.”
I have this problem! You plug in, and you can hear the distortion/amplification very softly (happens on clean channel too). I can turn the amp off and on a couple of times and it comes back. But once I start playing, after anywhere from 2 to 30 minutes, it goes soft again. Switch the amp off and on a few times and it’s back.
What do you think could be the issue?
Thanks,
Sal
May 26th, 2009 at 2:01 am
Hello Sal,
I believe Jason’s problem ended up being oxidation build up on the jacks. If this is the case, you want to get a good electronic contact cleaner, like the Peavey funk out that is one of my videos, or just about any Caig product at an electronic parts store.
If you’re in a real jam tuner cleaner at some tv repair shop if they still have that stuff. Do not use WD40.
Clean all your jacks very well by spraying a guitar cord jack and inserting it a bunch of times in the different jack holes and see if that does it.
I got an email in to Jason to see if that kept his problem cured.
Cheers,
Gary
May 26th, 2009 at 6:19 pm
Yeah, I will go ahead and do that. It’s weird because like I said, you can “hear” it at very low volume. The other weird thing is that turning the amp off and on solves it. Do you think that could be oxidation? It sounds like something more amplification-related or power-related.
Sal
June 2nd, 2009 at 4:54 am
hi there,
i just got my amp back from a friend of mine after touring and now my amp has this weird buzzing noise. its subtle when at about level 2 but anything passed 5 is just an annoyance. any ideas as to what it could be?
June 2nd, 2009 at 1:12 pm
Hello Shaun,
I guess the first thing you want to do is determine if the buzz is an electronic component failure or the speaker. If you can run the head through another speaker cab or whatever and see if you still have the buzz.
If it is a self contained combo amp there are ways to check the speaker.
If you switch cabs and the buzz is coming out of the new cab you have an electronic problem. There are different kinds of buzzes, for instance like an annoying ground buzz. Or a kazoo buzz that follows the note as it dies, a constant buzz in the background just on certain channels.
Caps leaking can cause a buzz, check what I said so far and see what’s up.
Gary
June 24th, 2009 at 12:23 am
Hi Gary,
I’ve got a Fender Twin Reverb 1980 Silverface (135W with push/pull master volume) which had hum problems, needed retubing and had static (sometimes could pick up radio) in the background too.
I’ve just retubed, replaced filter caps and cleaned the amp (no contact cleaner yet so need to go back in) and used the ‘Hum Balance’ and ‘Output Tubes Matching’ pots to reduce the hum and get the tubes looking rather nice.
The hum is still there but I think is the transformer??? This is slightly improved after the work. The sounds is clean but there is a problem with static in the background still. Any ideas for sorting the static?
Fantastic site by the way. Great information.
Thanks in advance,
Martin.
June 24th, 2009 at 2:17 am
Hello Martin,
That hum could be a lot of things. Here it is off the top of my head. First I would try to isolate the hum, pull the drive tube and move forwards and backward from there. If you still got it with the drive tube or leave the drive and pull the inputs and reverb, etc then it’s in the supply, if not check caps in the cathode circuit.
I’ve seen guys take the hum balance out and go to an earlier design. Do the 100 ohm to ground off the power light mod.
Not quite sure what you mean about the static, as the amp sits idle?
I don’t know about the transformer causing the hum, which one are you talking about?
Make sure you have good chassis ground for all circuits.
I guess the main thing at this point is you have to isolate the noise to get an idea of what the problem is.
Gary
June 24th, 2009 at 4:40 pm
Thanks for the swift reply Gary! I’m with the amp now so here goes…
Tube layout from Left – 4 6L6′s, 12AT7, 7025, 7025, 12AT7, 7025, 7025.
When I pull the 2nd and 4th from Left 7025′s the static/dirty electrical sound clears up completely but the hum remains softly. If either of these tubes get plugged in the static and hum comes back.
I’ve read someone else had this problem, did the pilot light 2 x 100ohm resistors mod and it didn’t solve the hum but I will try it if I can figure it out!
FYI – The amp doesn’t hum in standby mode with ALL tubes plugged in.
I’ve checked all ground solder points and all look fine.
Any ideas welcome!
Thanks again.
June 24th, 2009 at 6:04 pm
PS.When I’ve pulled the 1st and 4th 6L6 power tubes out, the hum is pretty much gone 100%. I’d be perfectly happy with this level of hum…now how the heck do I get rid of it!?!?!?
Thanks for helping me narrow it all down.
June 26th, 2009 at 7:36 pm
An update in case anyone else has similar problems:
1.The 2 100 ohm resistors to ground from the Pilot Light work a treat (don’t forget to disconnect the Hum Balance Pot) and get rid of my hum issues nearly 100%!
2.Cleaned contacts, tightened pots and transformers, checked all grounds and cleaned them.
The amp sounds clean, tight and loud now with very little background noise at all.
Thanks for your input Gary!
July 12th, 2009 at 7:12 pm
Hi how are you?
I hope you can help me. I am having a problem with my fender deluxe
I use the 4 cable method to connect my boss gt-8 and it works for a few minutes then the volume goes off. So I checked connecting directly to the input and the amp works great. Then I checked connecting to the power amp in and it doesn’t work. Do you know how can I fix this?
thanks, have a nice day
July 12th, 2009 at 7:34 pm
Hi,
Well lets see, you say when you go with guitar in to the input of the amp is works great, and then when you use the guitar to go into the amp in it doesn’t?
Is that what you are asking or your effects are going into the amp in?
If it’s the guitar into the amp in then the volume will be very low, you probably know this but just for time sake I’ll throw it in.
Gary
July 12th, 2009 at 9:50 pm
I got I boss gt-8 which has preamps already so I use 4 cables to connect it to my amp. So sometimes I use the fender preamp through the loop on the boss gt-8 and sometimes I use the boss gt-8 preamps. But the problem is the power amp in. It doesn’t work anymore.
I can here the guitar for a couple of minutes then it fades out.
So I try connecting the boss gt-8 directly into the input, and the amp works great but it doesn’t sound that good. And then I plug the gt-8 directly to the power amp in and it doesn’t work at all.
July 12th, 2009 at 10:12 pm
Hello,
well since we’re on the internet I would assume between the amp in jack and the output you have a problem. Make sure your tubes are lit up about the same and all are lit. Just for grins hook another good speaker *shot in the dark)to the amp make sure it’s not the speaker connection or speaker.
Other than that you have internal problems, could be anything from a bad amp input jack to component failure in the output section. Might be shop time.
Gary
July 12th, 2009 at 10:42 pm
thanks for the help. I’ll check it
have a nice day
July 15th, 2009 at 5:18 am
Hi how are you? I checked what you told me. I changed the tubes to my old ones and I have the same problem. When connected to the main input it sounds great. When connected to the power amp in it sounds great for a few minutes then the volume fades. Hope you can help me, thanks have a nice day
July 16th, 2009 at 1:36 pm
Hi,
If whatever you’re plugging into the amp to generate a signal, make sure it is constant, other than that sounds like the amp in jack or something in that area is bad.
If your amp has preamp out you could come out of preamp out to power amp in with a guitar cord, just completing the circuit. and then play your guitar into the main input on top like you’ve been doing when it was working.
This would verify if it’s the power amp in jack.
Gary
July 19th, 2009 at 5:46 pm
I have a DeVille that defies repair. It pops and snaps then it won’ no matter what you do. Turn it off, back on and it’s at it again or not. I have changed all power caps and the two 330 ohms resistors on the main board. The only thing left is replacing the phase inverter resistors and the 6L6 plate resistor change from 470 to 1K. Any further Ideas? I have seen this noise throughout the amp. Even on the B minus tube bias pot. When I jack in to the main amp nothing. The noise is in the pre amp. I am changing the resistors as a recomended up-grade of the amp. I need to find the pre-amp problem.
July 19th, 2009 at 6:42 pm
Hello,
Well it’s easy for me to suggest things but it sounds like you’re on top of it, maybe need to back off a bit and let the inner tech mind do some crunching and the answer might pop in,,works for me sometimes,
With that said here’s some things:::
If you go amp in with the signal you say the noise goes away, well then I don’t think looking in the output section is the place to start unless you feel there is some common thread like the power supply. Off the top of my head unless you’re front end ground is not exactly with the back end ground maybe there’s a gradual buildup of different ground voltages that discharges, otherwise I would look in the front end.
Does pulling a preamp tube do anything?
I would replace the cathode components on the pre amp, cap and resistor on the front end, sometimes in real old amps you get a frying sound when resistors drift or caps leak in the cathode.
Look at your grounds real well, on these newer Fenders the connectors can cause problems, also the way the wires can get crimps in them, the way they attach to the board.
Make sure you have good solid ground throughout. When you say you can see the problem on the bias pot but the noise can be isolated to the front end, again it’s got to be something is more ground than the other, as rear section is at 0 ground, pre fluctuates between 0 and .005 and discharges back to 0 or something like that…
Good Luck…
Gary
July 24th, 2009 at 8:17 pm
Hi
I have a really annoying problem with my Fender Hot Rod Deluxe. All the channels work fine but when i connect the footswitch it randomly switches between all three channels and sometimes switches back to the channel you’ve selected if you tap the footswitch. I connect the footswitch with a known good guitar lead so its not that. Any help would be greatly appreciated. PS I can handle a soldering iron, but I’m no electrician!
Thanks very much
Lee
July 24th, 2009 at 10:02 pm
Hi Lee,
The easiest thing to do is see if you can borrow a foot switch from another unit and make sure it’s not in the foot switch. Other than that it could be aswitching FET in the amp. Which takes a little finesse to replace. If the problem is in the amp might be best to take to a good repairman.
Cheers,
Gary
July 25th, 2009 at 7:26 am
Hi Gary
Thanks very much for the quick response. I’ll try it with another footswitch today and if it’s not that I’ll take it to a repair shop. Thanks again, I’ll be recommending your site to all my friends!
Lee
September 16th, 2009 at 12:52 am
Hello Gary -
Great website and video. Not sure you can help me. I have Fender “The Twin” with only the clean channel working at the moment. The dirty channel give no sound at all. Also, after warming the amp up for about 15 mins and playing for a short time the clean channel increases in volume. Do you think the two problems are related?
Jerry
September 16th, 2009 at 1:39 pm
Hi Jerry,
If you have a channel out, you got problems right? (no pun intended) if you noticed both problems at about the same time, they probably are related.
Are all your pre-amp tubes lighting up? You can switch pre-amp tubes and check if it’s a tube, (not sure if you have a re-issue or like my Keith Richard’s tour video) Just make sure you’re switching 12AX7′s,, don’t switch out a 12AT7 by mistake.
Not sure where you are on your repair chops, might be shop time.
Gary
September 26th, 2009 at 4:39 am
Hello Gary -
I still giving “The Twin” the once over to find out why the gain/lead channel is dead. All the 12AX7′s light up although dimly. Jiggling the tubes does nothing and I did switch around the 12AX7′s which by the way are brand new. I tried sending guitar signal feeds to monitors suing the preamp and amp through connections on the back of the amp. Only the clean channel comes through. I do not see any loose wires.
Can the amp choke or any of the LDRs cause this problem? Or should I be looking elsewhere?
Thanks for any assistance you can provide.
Jerry
September 26th, 2009 at 3:59 pm
Hi Jerry,
From listening to your problems I would say you are going to need test equipment to zero in on this one.
It’s not the choke, and the LDR’s, I’m not looking at a schematic, but I’m not sure this unit uses them.
Usually they are switching FET’s are used in channel switching ciruits, could be wrong on this unit but a lot of the re-issues use FETs and they are prone to go bad. But that may not be your problem. I would say you need to follow the signal path in the dirty channel and see where you are losing it.
At bare minimum you’re going to need a good volt meter and a schematic. And remember one wrong poke inside a working circuit and you got 2 problems. I’m all for learning/teaching electronic repair but like I always say, don’t get your chops on amps that you depend on.
Let me know what you got for repair equipment. sometimes
Gary
October 20th, 2009 at 3:53 pm
Hi,
Has anyone solved the “buzz in drive channel” -problem that Gus had?
My HRD does same thing now. Clean channel works fine (so far), but drive channel starts buzzing when i’m turning bass knob up to ~”4″-position and over.
Any ideas?
October 20th, 2009 at 4:18 pm
Hi,
Do you remember what post that was? I don’t see it in this thread. I’m at the point I may need to turn the site into a forum, would be easier to navigate.
Gary
October 20th, 2009 at 4:24 pm
Hi,
Oh, ok I see it now. Single channel problems are hard to diagnose over the net. I would need detailed info and the person looking at the amp would need decent repair equipment.
Other than changing out tubes, and hooking up different speaker cabs there’s not much that can be done.
Gary
October 28th, 2009 at 4:40 pm
Hi Gary. Been looking at your helpful site and can see that my problem is common. My HRD has been making a low buzzing and popping sound too. Recently got much louder and blew altogether. Shop replaced two valves. Good to go? No! It’s came back, low hum with pops/crackles even with no instrument plugged in and at low/no volume.
Help!
October 28th, 2009 at 9:33 pm
Hi,
If you’re saying it came back from the shop still humming, you may need to take it back and tell them they missed something. The low hum could be different things, power supply, bias, pre-amp, drive section but if it’s loud enough for you to notice you may point it out to the tech.
Depends on which tubes that were replaced, when it blew did it pop a fuse or just the tubes, was it pre-amps or outputs…Regardless I would take it back to the shop and see if they can rectify the situation, might of sounded good during final checkout but still have something wrong with it.
Cheers!
November 29th, 2009 at 10:48 pm
Hey, great Q & A. Fender Hot Rod Deluxe issue:
The drive channel works, but it sounds like it’s got a humming vibrato effect. The repair shop suggests it might be a loose tube. Does that make sense, or is it a shot in the dark?
November 29th, 2009 at 11:47 pm
Hi,
Maybe what they mean is there’s a component connected with one of the tubes is loose from the board. The tube itself, I doubt is causing the problem.
All you would have to do is make sure they are all pushed in and tight.
I would suspect component failure, but always check the simple stuff first.
Good Luck!
December 8th, 2009 at 5:14 pm
Hi Gary,
Great site, your knowledge and advice is very much appreciated. I have a question about my Hot Rod Deluxe. At my last show, I turned the amp on in standby mode. Set up the gear and when I flipped the standby switch to “On”, the amp lost power. When I got home I saw that the fuse had blown. I did some research and read that failing power tubes may be the culprit, so I replaced both power tubes and fuse. Again I turned the amp on in standby mode and it powered on, but as soon as I flipped the standby switch, the fuse blew again. Any thoughts on what may be the cause of the problem? Thank you for your time!
December 8th, 2009 at 8:36 pm
Hi,
If I had to guess off the top of my head I would say it’s one of the power diodes. The downside is on this amp the pc board has to come out to get to it correctly which is an ordeal if you haven’t done much repair.
I’ll try to post a snapshot of the power supply. There are other things in the high power section that could blow the fuse but this solid state diode array is probably the answer if you switched out the tubes.
Other thing could be the output transformer, but hopefully it’s a power diode, which usually goes out. Sometimes also, I can’t remember on these amps but if there’s a lot of stage light activity in a small club there are some protection diodes on the output transformer that will short also instead of the transformer, but again I bet it’s a power diode.
I would say it’s shop time, you want this repair done correctly, I can’t think of anything besides of what you already performed unless you’re up on repairing amps.
Good Luck!
Gary
December 8th, 2009 at 9:05 pm
Thanks Gary! I truly appreciate your help.
February 4th, 2010 at 12:59 pm
Hello Gary,
First of all, thank you for posting such great and informative videos, they’ve been extremely helpful! However, I have a question in regards to the Peavey Funk Out you’re using. I was just curious as it’s difficult to notice in the video if you’re shaking the can or spraying it, but are you solely using the spray to clean the pots / inputs, or are spraying the product directly onto the circuit board?
Thanks in advance for any help and thank you again for your useful videos!
All the best,
Michael
February 4th, 2010 at 1:41 pm
Hi,
Thanks for the comments. I’m just shaking the can to build up pressure inside the can. I’m spraying inside the pots, in most pots in amps there is a little indention (hole) or an opening near the lugs (points where the circuit is connected).
I usually spray the guitar jack (end of the audio cord) with cleaner and work that inside the jack, or you can spray inside the amp input jack and work the guitar plug in and out to clean.
With Funk Out you only need a little squirt. I try to keep it off the circuit board.
It won’t hurt anything, it’s not conductive but sometimes cleaners will leave a filmy residue on the board. I usually turn the amp off while cleaning anyway.
Gary
February 4th, 2010 at 5:08 pm
Gary,
Thank you for the taking the time to reply to my question, it’s greatly appreciated.
All the best,
Michael
February 16th, 2010 at 2:48 am
hello,
having a problem with the reverb not working on a hot rod deville 212. checked the connections on the circuit board, the rca jacks on the reverb tank, all intact. still doesn’t work. rest of amp works fine. any ideas?
February 16th, 2010 at 1:21 pm
Hi,
I assume you checked the reverb driver tube? Also the pan transducers inside. Are the wires still connected, sometimes they break, (the part that attaches to the springs)
If you have done all this, do you hear the pan “crash” if you shake it, while it’s hooked up? That will tell you the problem is before the pan, if you don’t hear anything suspect the pan or what’s after it.
Gary
February 16th, 2010 at 2:49 pm
gary thanks so much. but that’s just it: i’m not sure which is the reverb driver tube. there’s 5 tubes altogether: 2)6L6gt’s and 3)12AX7′s. is it one of these or is the reverb tube something totally different? at any rate, thanks for the quick response.
February 17th, 2010 at 4:51 pm
Hi,
For some reason my Hot Rod Deluxe schematic PDF is unavailable so I pulled up a Blues Deville schematic and noticed the drive is an IC so if the hot rod is the same you’re out of luck on the troubleshooting.
best thing to do is pull your preamp tube covers and make sure they’re all lit. small glow at the base of the tube is the heater.
You could switch tubes BUT some may be 12ax7 and a couple 12at7, you do not want to get these mixed up, the amp will still work but the quality of the sound will suffer greatly.
SO until I can find a schematic I would just make sure of the things I told you so far, make sure it’s not the pan.
And if you’re unsure about anything I’ve said just don’t do anything to your amp till you get with someone that knows a thing or two or it can cost you more money when you get it fixed.
Gary
February 17th, 2010 at 4:53 pm
Hi Adrian,
Just noticed you said there are 3 12ax7 tubes, I would say this has IC reverb driver, this is a whole different layer of troubleshooting that will need to go to an experienced tech.
Gary
February 17th, 2010 at 9:43 pm
gary,
i can’t thank you enough for taking the time out to look. i’ve done some extensive research on it and have come up empty. but to my surprise, i’m still covered under a 5 year warranty even though i bought it from a friend last year who bought it new. thanks again.
June 28th, 2010 at 12:21 pm
i have a fender blues deluxe and recently started crackling after playing for a little while and losing volume not got gone completely but lower
June 28th, 2010 at 12:35 pm
Hi,
Well there are a couple of things to check…next time it does it, check out the large output tubes, is one glowing brighter than the other? If so, turn it off an take it to a shop.
Or you could have a component coming loose from a circuit board which again is a shop repair if you are not experienced at working on amp.
The simple thing would be a tube, so make sure they are all pushed in and seated correctly the next time the amp is off and cooled down.
Also switch out guitars and cables and such, make sure it is the amp.
Gary
June 28th, 2010 at 7:17 pm
i checked the tubes one of them i could barely see the pins could that be it the other one u couldnt see the pins and they are pretty easy to pull out is that normal
June 28th, 2010 at 7:52 pm
HI,
I assume you’re talking about the output tubes. If you made sure they’re pushed in and you still have the problem, it’s probably something else.
If you do have loose tubes, the socket pin holders need to be tightened and that will need to be done correctly and safely at a shop.
The tubes should be snug but not hard to pull out.
Gary
July 6th, 2010 at 12:25 am
so i tested my amp for about an hour it seems to make the noise when turn the amp up louder and the tubes were warm but not real hot
July 6th, 2010 at 1:54 am
Hi,
It’s kinda hard to say what it is. If you have some spare tubes you could switch out tubes and see if the problem goes away. If not it would probably be easier and cheaper to have a shop check it out. Sometimes having some good used tubes on hand is nice but I wouldn’t spend a lot for them because it still might be something else like a component.
Gary
July 6th, 2010 at 2:00 am
i dont know if old tubes bias are different shouldnt they be the same
July 6th, 2010 at 12:31 pm
Hi,
With the diode and small input, drive, reverb tubes bias would not be an issue. With the output tubes yes, but what you’re trying to do with switching the tubes out is to see if you’re problem goes away. Then you’ve located your problem and move forward with buying new output tubes or biasing your amp to fit the new (used) tubes. If you still have a problem then you know your problem is something else and proceed accordingly. If you’re a tech then you start checking voltages and eyeballing the circuit, watching it on a scope at the different stages, etc. If you’re not a tech it’s shop time.
Gary
July 6th, 2010 at 4:18 pm
so i tried both tubes and both times my sound was not as clean as usual alittle distorted even turned down low volume
July 6th, 2010 at 5:14 pm
Hi,
Sounds like it might be time for the shop.
Gary
July 12th, 2010 at 4:39 pm
it was a bad plate cost 80 bucks to fix
July 12th, 2010 at 4:42 pm
Hi,
Are you saying that one of the tubes were bad or a component connected to the plate circuit on the tube?
Thanks,
Gary
July 21st, 2010 at 1:44 pm
Hi Gary,
Have a HRD that emits very loud low-pitch hum noise even with all controls @ 0.
Checked for cracked solder joints ’cause I’ve had that issue before.
July 21st, 2010 at 2:15 pm
Hi,
I would suspect the power supply if you haven’t checked it already…if you have noise with all volume turned off. Also check around the output tubes, does the sound go away if you pull them? Is one output brighter than the other? Of course be careful, I don’t know your skill level, I would assume if you’re repairing solder joints you know something about repair.
Gary
July 21st, 2010 at 2:53 pm
Noise still there w/ tubes pulled, same luminosity from both.
What would I be looking for when checking the power supply? I’m fairly competent with electronics, particularly signal processors, but I don’t know much about amplifiers.
July 21st, 2010 at 6:03 pm
Hi,
You probably have a problem in your power supply, it’s going to be a cap or a power diode. I don’t know the age of the amp but, I would eyeball everything in the supply with the power off. Lots of time you can see a cap leaking or possibly the diode created heat. Also you can check the diodes, just make sure to discharge caps and such when working in there for safety and preventing false readings.
If you can’t see anything, you may want to take voltage readings or look at your amp on a scope.
Just remember these can pack some current, so you don’t want it discharging through you or your equipment. I usually use a 100 ohm 5 watt to bleed caps to ground before poking around.
Good luck!
July 21st, 2010 at 6:07 pm
Hi,
I need to quit doing 2 things at once :), it’s probably not a power diode unless it opened because if it was shorted it would probably be blowing fuses.
You probably have a bad cap but kinda hard to troubleshoot without hearing the sound and taking measurements on my end..
G
July 24th, 2010 at 4:50 pm
Unfortunately, all the caps (& diodes) look to be in great shape. It looks like one of the power resistors has gotten hot at some point, perhaps I’ll try flipping it for a new one.
Thanks so much for your thoughts!
July 24th, 2010 at 7:26 pm
Hi,
On the power resistors, possibly, depends on which ones. If it’s the step down FP, those generate some heat which could be that the legs have pulled away from the board or a component near them. Continuity test would tell.
If it’s the resistors leading to the 15 volts feed, now that may be your problem…did you check the voltages 15 v rails? May have lost a zener or an Ic.
There’s a schematic at http://www.fender.com/support/amplifier_schematics.php if you don’t have one.
Gary
July 30th, 2010 at 9:33 pm
I have a 2002 hot rod deluxe. If you tap about any where on the amp it crackles. I opened the back and when i tap around the curcit board, knobs, or compontents it crackles. It seems worse when i tap on the GT6L6B tubes. and one tube worse than other. Would bad tubes cause it to crackle even when i tap on the outside case?
July 31st, 2010 at 1:13 am
Hi,
It may be a tube, if you have a known good tube to replace each one and see if the noise goes away would be the quick thing to do.
Gary
July 31st, 2010 at 1:50 am
switched the 2 tubes now it is dead, so i think re tube it all. Is there matched 6L6 and the other 2 in a pair then 1 single?
I will start with only 2 6L6 and see.
Unless you have a better thought.
July 31st, 2010 at 2:09 am
Hi,
I’m assuming you switched the output tubes with tubes that are not from this amp? It shouldn’t be dead. Something doesn’t sound right.
It’s really hard to troubleshoot on the net, from what you said so far, I would take it to a shop or to a friend that works on amps. You could buy tubes and still have the problem.
Just my 2 cents.
Gary
July 31st, 2010 at 2:18 am
no switched 1 output tube for the other. same tubes different plugs. Is that bad?
July 31st, 2010 at 2:23 pm
Hi,
So you’re saying you switched one GLG for the other?
If you did, the amp shouldn’t quit working, even if one was noisy. Are you sure the bottom part (plastic) guide tip (inside the metal pins circle) is not broke off? You would be able to see the glass of the tube from the bottom if it was.
And besides, tubes going bad ( unless they cause a short from the above problem or a tube destructs internally) is not going to make your amp dead.
I would put it back the way it was and see if it comes on. I’m not saying it’s not your tubes but at the same time I can’t say it is the tubes. There’s nothing worse than buying 2 6L6′s and still have a problem. No one is going to take tubes back.
Gary
July 31st, 2010 at 10:38 pm
Thank you for all your information.
Turns out one of the solder connections on the ribbon cable to the preamp tubes had a loose connection on the curcuit board. The ground wire was also loose on the circuit board.
I removed the board and re soldered the 2 connections. I put it back together and it sounds great and every thing seems to work. Thanks again and have a great day, I know I will be rocking.
July 31st, 2010 at 11:23 pm
Hi,
Fantastic…good eyeballing there!
Gary