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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Hi,
That sounds like “possibly” the speaker but not a sure thing. I’m not familiar with that model but I assume it’s a St Louis Music ampeg. The best thing to do is figure out how to use the head to run a known good speaker or play another head through the 220 speaker and see if you still get the buzz.
You can also pull the speaker and have a speaker tech check it or sometimes if you press on both sides of the speaker cone with your hands so it’s an even push in, you can hear the speaker scrape but I wouldn’t do this unless you know what you’re doing, get an experienced tech to do it.
If it’s not the speaker, sometimes a clamping FET or other component going bad will cause it, possibly even an IC on the input or even a smaller cap in the supply but 80% of the time it will be the speaker.
G
Hi,
I have a Hot-rod deluxe I’ve been troubleshooting.
After dealing with the plate load resistors on the phase inverter, the amp is loud and crackle free again, but now I can hear this strange ghost note that hangs, distorted and much lower, only when I hit a ‘C’ note. On sustain, the ghost note will start cutting in and out sort of like a gate with a sharp threshold. It only happens on this note.
My first thought is that 1) one of the chips is bad or 2) one of the filter caps to the chips is going bad.
Any thoughts?
Cheers!
You know I think I’ve seen some reissues do this but I can’t remember what it was right now, it will come to me. I doubt it’s an IC or supply, they’re usually not that selective when they start going out.
I assume it’s a low C? Possible resonant frequency of the amp cabinet (so to speak) shakes something loose that gets in the signal path or another idea will be small component in the signal path. Have you tried different input and drive tubes? The cutting in and out is the strange part or I would say run to a different set of speakers.
Hi Gary,
Thanks for the response!
The issue actually happens at octaves too…
it is very strange.
The reason I thought it chip related has the nature of how the ghost note cuts out when the sustained note rings down. It seriously sounds like its hitting the threshold of a noise gate, cuts in and out a few time (literally on and off, like a gate) and then cuts out. Also, I have to dig in playing a little to get it to happen…
Also, this issue happens on both channels in the same manner.
very curious…
Thanks again, Gary!
Hi,
Is there an IC in the signal path common to both channels on that amp?
Since it is on both amps I would pay attention to the supply, possibly reverb and back at the output.
Was it doing this before your work? If not go over what you were doing and check your components.
Only happening on C is the strange part. Does sound like a cap charging and discharging but I’m just guessing. since it’s only happening on C, I would look for simple things first.
I meant to say since it’s in both channels. Also I’m not sure what blew before your repair but look at components that were in the vicinity or attached to the circuit that blew, one could be taxed to the limit now because of the failure.
The amp had low volume and intermittent squeals.
A little research led me to the issue with the plate load resistors fatiguing (I read somewhere that Fender actually had a bad batch of 100K 1/2Ws at the plant).
I replaced the 100K at the PI (r58) but haven’t done the 82K (r57) yet.
Coulda sworn there was a TL072 in the audio path somewhere…
Ah ha!
You were correct. I replaced a tube with another bad tube in the V1. Totally microphonic.
So far, the amp sounds good.
You, sir, are a great resource.
Cheers!
Hi,
Great!! It’s always nice for the problem to be something that you have in stock.
G
Gary
I have a fender hotrod deluxe and I’m having an issue
I just put in a celestion g12h and I turned it on and the volume is very low and my tone is really off.
any suggestions?
Hi,
Was the amp working before you switched the speaker? IF it was then check your wiring or the speaker you put in could be bad.
G
Have a 1976 Silverface Fender Deleuxe reverb which recently had all the tubes replaced by a authorized Fender tech about a year ago. My problem is that when I plug in on the Vibrato channel side there is faint low level of volume leaking when the volume knob isturned down to 1 for some reason – I mean you can still hear your guitar even if you turn the knob down to 1. It’s not loud but it is there!
Other than that the Normal channel volume, treble, bass knobs and all other Vibrato channel knobs work at all levels.
Hi,
One thing you can do is try and isolate the problem, if you know how, pull the small input tube at the far end ( if you don’t know what I mean, best to not do it because you have to put it back in correctly, line up the pins with the socket) see if your problem goes away. If it doesn’t there’s a couple of things to look at in the reverb vibro circuit.
G
Hey man,
I have a deville 4×10 and last night channel one pretty much died. At first I removed my pedal board from the signal path and went directly in but all I got was a crackly sound which eventually stopped all together. So I tried Channel 2 and made it through the night with it. But Channel 1 remains dead. Any ideas?
Hi,
Could be an input jack, tube or switching FET for starters. Make sure tubes are seated properly, like the 2nd one in (the small ones) You could switch input tubes but unless you know what you’re doing it could just cause more problems. Might be shop time.
G
I’m a “Pro” with some amp building under my belt. I made the original Fender Champ years ago. So I have some decent tube amp knowledge. although I know that the deville is a printed circuit board… so my vintage knowledge is a little useless here! ahaha
I’ll try the 2 things you suggested and let you know.
Thanks for the quick response! I appreciate your time.
Hi,
In that case drop me a line at buckapple at gmail and I’ll give you some tips.
G
Hi,
Before taking a look at the amp. Does it exhibit this symptom at different locations? Sometimes amps will do this if too much equipment is going to the same power source.
If that’s not the case, as far as the power light dimming, something could really be sucking the current but not enough to blow the fuse but it seems like over time it would go ahead and breakdown. Make sure you have the correct rated fuse for this amp.
It could be something intermittent, if it’s not a location problem and you have limited repair chops I would take it to a good repairman and have him/her locate and fix the problem before it blows and really cost some bucks.
G
Hey hey!
Sorry if you’ve been asked this question before, but I barely made it through my audiotronics course and am a moron when it comes to amps and circuitry…
My 1×12 Hot Rod Deluxe combo has a mind of its own at times and the sound drops out (usually after about 1 hour of playing above 4 which is pretty loud–I’ve never played at 10) but does not completely go out. I see that the pilot light gets very dim, and brightens only enough to coincide with how hard I am strumming my guitar. This is all with me going straight plugged into the amp. I’m thinking I need to replace the tubes since I bought it used, but could this be an issue with the fuse instead? AND how often is it recommended you change tubes/fuses?
Usually just as a temporary fix, I unplug the amp and plug it back in which seems to give it some juice enough to keep playing full blast for a little while. Is that normal?
I’d appreciate any advice. I just hope I don’t have to solder anything, hahaha. Thanks a bunch!
Hi Gary,
I just stumbled across your site and would like to pick your brain a little. It sounds like I am having the EXACT same problem with my Hot Rod Deluxe that “Gus” outlined here (beginning on post #17). I have barely played the amp since new since it doesn’t really fit my style, so I have decided to sell it. The clean channel sounds okay, but breaks up MUCH earlier than normal, but the gain channel is doing the same buzzing thing. The only thing that seems to affect it is the bass knob when it’s on the gain channel. I tried to watch his video that he posted but it has been removed. Did you ever come up with a solution? I can’t imagine it would be anything serious. Like I said, I have BARELY played it an when it wasn’t being used it was kept in my climate controlled studio unplugged. Any advice would be greatly appreciated!
Thanks!
Jeron
Hi,
Well it could be a tube, a cap in that area, a switching FET, an active component. So it might be time to take it to a tech if you’re not up on repairs. Seems like some people are having some cap failure right in that area. What I ran into was FET switching failure most often. Make sure it’s not the tube other than that it’s not an easy amp to work on.
G
Hi My Fender Ultimate Chorus amp crackles when i play, thought it was a lead problem but have bought a new one and it still does it. The sound is as if its the input jack on my guitar is faulty but that has been checked and is ok. I do use foot peddles , but have tryed it with just the fender foot switch and it still does it. It a bit inconsistant, as in the past it cracked but then stopped, however now it seems to be getting worse and is constantly crackling. Have you any ideas, hope iv explained it well enough.
Hi,
Not sure what you mean by “lead”, I guess you’re saying cable? Anyway it’s hard to say. The easiest thing to do is run a guitar cable from the effects send to effects in and see if that is it.
Sometimes those jacks need cleaning. If not, could be something inside needs resoldering and it doesn’t separate until the amp is vibrating from playing.
Unless it’s something simple like a jack cleaning, probably time to take it to a shop. Shouldn’t be too bad, repairs like this are “usually” not that involved.
G
A friend gave me a one year old HotRod Deluxe. With no guitar plugged in, if I select the drive channel and put the master and gain up around 10 there is a very loud roar. Is this normal for a tube amp? I’d like to use this for more blues oriented gigs, but I mostly use very clean solid state amps for my much more frequent jazz work. One one gig, however, even using the clean channel I heard a few sudden loud nasty “blap” sounding distortion events which tended not to happen if I avoided low notes/chords.
Hi,
NO it’s not normal for a tube amp to do that. I would say it’s time the amp went to the shop, could be anything from bad jacks, speaker, component failure, a combination of two of these like the loud hum with the flap noise for example.
G
Gary,
I have a 1994 Super 4×10 Combo, amp # PR 244 that has started making the “bacon frying” noices intermittantly. Is it due for all new capacitors and resistors? The tubes all check out good, pots have been cleaned, sockets are good. I’ve heard many Fender amps get this problem. Can you recommend a good cap/resistor replacement kit?
Thanks,
Mark Cate
Hi,
Sweet amp you got there. Please don’t let anyone hack on it…LOL
Basically what I would do is change anything that has looked at high voltage over the years, resistors, caps in the supply and output section. The 100k plate resistors on the preamps at least.
As for kits, I haven’t kept up with that but would imagine there are some that touch the bases I mentioned and then some.
Cheers!
Gary
Not sure if this site is still active, but I have a Fender Hot Rod Deluxe that will not go into the distortion channel. Sometimes it will kick in for a second and then go back to clean. The red light for the drive channel will sometimes will sort of pulsate but will not come all the way on, except for those brief seconds when the distortion kicks in. Same thing happens with or without the foot switch plugged in. Any ideas what the problem might be. Also, my main power light is out, though that’s probably an easy fix. Thanks.
Hi,
About the site being still active, Traffic to the site has been slow since the last google updates.
On your problem, from what I’ve seen if the foot switch is ok which sounds like it is since it does it from the panel. Usually when the switching FET’s go out, there not intermittent, they just go out. I would say a bad connection on the component board. Perhaps a ground somewhere, might be a simple fix but if you don’t know what you’re doing, a shop should be able to nail this for you.
Good Luck
G
Thanks. I watched your video and did the drumstick technique, and there was some “popping” when I tapped on any of the vertical cylindrical components on the board that say IC 500v, 47uF or 22uF. Also, when I tapped on the red plug that connects underneath and at the edge of the board that runs over the top of the tubes – the edge closest to the speaker jack. I probably should take it to the shop, but it would be good to have an idea of what the problem is before taking it in. Thanks.
Hi,
On these amps you really can’t go by popping and such. I believe I was demonstrating how to find intermittent problems. For example if you were tapping around and your switching problem disappeared, you would be in the vicinity of the loose component. (hopefully) but if it’s just popping and such on these amps, that could be a sensitive tube or a strange ground or possibly a bad component but you would need more diagnostics using repair equipment. I doubt the popping is related to your original problem.
G
Hi Gary,
I have a ’97 HRD 4×10. No sound from any of the two input jacks. Power amp in is ok. New tubes still the same. I will be checking for any solder cracks since it had one in a pre-amp socket last year. If after checking it’s still the same would an upgrade kit like this one on Ebay come close to a solution? http://www.ebay.com/itm/Fender-Hot-Rod-Deville-Supreme-Mod-Kit-by-Fromel-/180951115044?pt=LH_DefaultDomain_0&hash=item2a2186e524
Hi,
If that amp has a preamp out, run a guitar cord from the preamp out to the power amp in and see if you get your signal back. Sometimes jacks open or the problem is in that area, like oxidation. Otherwise you still have a problem and getting an update kit will not fix the problem, only give you a potential to chase your tail even more so to speak.
Good Luck!
can you please tell me the lgtenh, width and height of these strat and les paul type guitar lamps as well as the price and availability?ThanksSteve
Not sure what you mean on this, I don’t sell anything.
Hello Gary,
I have a used Fender Hot Rod Deluxe that had no reverb tank when I got it. It worked great for a few years but recently stopped getting sound after the tubes warmed up (after about a minute or 2 there is no sound. I have a little technical aptitude and re-soldered R78 & R79. It started working just fine after that so I bought at reverb tank and expected it to work, but didn’t. I looked at all the reverb components and pot and re-soldered some connections and now I only get sound for a minute or 2 after it warms up (1st problem above) and still no reverb. The RC connections are clean. I tested the replacement tank on another amp I have and it works just fine. Any suggestion?
Hi,,,this is armchair quarterback answers on this one. Getting the amp without a reverb tank suggests to me that the amp had reverb problems that someone couldn’t figure out and the tank ended up in another amp over time. OF course this is speculation unless you know the history. Either someone couldn’t fix it as in over their head, or they perhaps put in a wrong part or bridged something etc and made the problem worse. You didn’t mention your test equipment besides soldering so without a scope, I guess take voltage readings in that region or resistance readings after amp sitting for a day or so and see if you have breaks or paths to ground where there shouldn’t be any. Also a small side note, with some amps you can see the signal up to the pan and tells you a lot if the problem is pre or post pan…but sometimes that are is mostly current and will not show well on scope.
I think you said the original problem is back? If it is and after a couple of moments something warms up and cuts the signal path. The only thing I can think of and a long shot is gently tap on each component with something like a drum stick and see if it cuts out on you, like around preamp tubes…or when it cuts out put the guitar in the effects loop receive jack and see if you can hear it at all. Helps you isolate the circuitry. Or you can effects loop out to another amp and see if you get the signal…
Do all the tubes stay lit when it cuts out?
Hope any of this helps.
Another long shot…there are different types of tanks…make sure it’s the right reverb tank for that amp…the transducer impedance on the input where it feeds the springs must match the circuitry of the amp…you would probably still hear a faint signal with the wrong pan but maybe not.
Gary,
Thanks for the advice. I don’t know the history of this amp so I’ll bet your right that someone tried but failed to fix the reverb issue. I don’t have a scope so I’ll take voltage and resistance readings to see if I have breaks or paths to ground where there shouldn’t be. The replacement tank I purchased was the MOD 9EB2C1B. As mentioned in my first message, I did check it via another amp and it worked fine.
As far the original issue of dropped/no volume after warming up, I turned it on last night and it stayed on for over an hour so I’m not sure why it wouldn’t turn stay on then now it does. I went home for lunch yesterday (when the volume would cut off) so I inserted the 1/4″ jack into the POWER AMP IN jack and no signal there either (this was before I turned it on last night when it worked and stayed on for over an hour).
All the tubes stay lit. I still have my old tubes (which I changed out a few years ago) and placed them back end and still works but with no reverb.
I’m going to replace caps C31, 33, 35 &36 and resistors R78, 79 & 97 and diodes CR13 &14 (found in the HRD Service Manual schematic).
I’m curious to know if you think it can also the reverb pot being dead. Your thoughts and comments are always insightful.
Regards,
David in Abilene TX
The reason I’m thinking it may be a bad reverb pot is because all the other pots function correctly. Just a hunch.
Thanks Again!
If you inserted a 1/4 in to the effects in and no sound (assuming signal is from guitar) you should have heard something, if you didn’t you can look for the problem after that point…unless it’s something common to the circuits like the power supply. I would guess you’re problem is going to be more of a trace to ground or almost broken trace somewhere. Components put back in wrong or wrong component inserted. On the pot, I doubt it, more like a trace to or from the pot.
I’ve seen many problems on the reissue’s just being the effects jacks needed cleaning but that’s usually from the get go, not after a warm up….anything is possible. I can’t remember on that amp but the clamping FET’s can mess up sometimes…fet’s that mute circuits or switch…on that amp, (there’s an article on this site about it somewhere) it may have mechanical relays doing the job..maybe look in that area but you need to isolate first…you may have 2 different issues…I always look for simple stuff first…sometimes just looking at all your data from readings, looking at the schematic and thinking about it will produce quicker results.
Hi Gary,
While I’m waiting on some components I’m trying to understand the FHRD signal path. I created a document (in the link below) that outlines what I think the signal path is but need to ask you if you can confirm it or make corrections. I used the service manual schematic and used colored lines to show the path. Can you review it and let me know if I’m even close?
I do appreciate your time.
Regards, David
http://www.tdpri.com/threads/fender-hot-rod-deluxe-signal-path.639364/
Hi..I had a reply and got erased…jeez…basically from what I can see, your schemo blurs out when I enlarge it. You’re close it seems, one way to learn it is inject a signal and follow with a scope around. Keep in mind where something is current driven the scope signal is hard to see on run of the mil scopes. I’m not sure if you have a problem or this is for education. Do a search for How to troubleshoot audio amplifiers’ it was a book by Jack Darr or something like that years ago where he traced out signal paths. All my books are no longer or I would look. Also a very good resource is the guitar amp handbook, that guy breaks it down,,,I mean “breaks it down” if you want to know what a tube amp is doing that book will blow your mind,, http://aztechmusic.com/resources/ A guy at Groove Tubes turned me on to it years ago.
Someone commented about reverb…part of the signal goes to reverb but I would look at it as a parallel signal goes over there to the tank..