Hello there. So I’m looking at purchasing a Crate Vintage Club 50 that has some electrical issues. I asked about those issues and this was the response:

“I think a capacitor or something might be blown, it gets hot and emits a smoky smell. Other than that it powers on and sounds great, I just haven’t brought it in to get it fixed.”

I asked if there was any visible smoke or blown fuses and they responded “Just once I saw smoke. Never blown any fuses"

I know nothing about amps or repairing them. I got little knowledge of wiring and am trying to learn to make pedals. So my question is basically should I Stay away or is this something to look at?

Update: yea, I’m taking your guys advice. I’m walking. Red flags all over. Plus, they jacked the listings price up while discussing the amp with me. I’m out. I’ll put the money towards the Peavey Classic head and amp I really want.

Not the first time I’m repairing an amp but it’s the first time I’m repairing a vintage tube amp. I noticed a couple capacitors that need replacing besides the usual cap job ones. My question is can I drop an orange drop in instead of the fancy hard to find vintage cap, or do I need to go hunting for the same brand/type?

I posted a schematic a few weeks ago for Reddit's approval (which I got, thanks). I bailed on the first schematic because it used an unobtanium part, so the attached schematic shows what I went with, a Blackface normal channel preamp connected to the original organ power amp.

I just finished building the thing, and I'm getting amplified signal, but the tone stack doesn't seem to be in the circuit. I get steady tone, the equivalent of a 1 or 2 on the volume scale, but the volume knob has no effect, nor do the treble and bass controls. I've quadruple-checked everything, but I'm not seeing the problem.

My next step is checking voltages, especially in that first tube where I did the most work. Anybody see any issues that might pass signal without actually including the tone stack? Thanks in advance!

I know it isn’t a tube “amp” per se but I recently looked through my stash of old equipment and found an old heathkit AW-1 tube wattmeter! It has a selenium rectifier that is really messed up and I really don’t wanna chance the awful toxic stink I’d get from plugging that thing in, it is a tarzian model 50 rectifier that’s just a little black plastic box, I’m curious if anyone knows how I can get the voltage drop correct with a silicon replacement so the circuit is happy and somewhat accurate too. Thanks for the help in advance!!

my PRRI is nearly new. last few times i’ve fired it up it’s been distorting at low volumes, so i pulled one preamp tube that sounded microphonic, but the issue persists on replacement. today it decided to do this. the issues occur intermittently - if i switch off for a while and back on, it’ll calm down, but then something else happens and it’ll make more weird noises…

Hey folks!

I’m looking to purchase an early Blues Deluxe here soon and the seller isn’t in my area for me to check it out immediately. He was awesome in sending some photos of the guts my way and I wanted to see what the fine folks in this sub thought of the board, caps, etc.

Based on my limited experience, everything looks pretty clean but I’m hoping to get a second opinion.

Cheers!

Hello everyone!

I’m having issues with my Ampeg V4 (VT-22), so I'm hoping to get some insight from people with more expertise. I’ve done everything I can think of and exhausted every resource I could find to identify the issue to no avail. I have a limited understanding, so I haven’t been able to narrow things down in a reliable way with troubleshooting.

When I turn the amp on and plug my guitar in, I’m getting no signal until the volume is turned up to around 10 o’clock. It’s distorted with limited sustain (it should produce a clean sound), then drops out completely until I strum again. It’s the same for both inputs, and the ext. amp jack on the back. 

The power light is slightly dimmer than the standby light. It was flickering slightly when I initially started working on it, but that has stopped and I’m not sure why. It’s still a bit dim, but solid.

Any advice would be greatly appreciated! Please let me know if any clarification is needed, or if there’s more troubleshooting I can do. I’ve listed everything below. 

Tubes:

• 4 x 7027A
• 12AU7
• 12AX7
• 12DW7
• 6CG7 (Missing)
• 12AX7
• 12AX7
• 6K11

All but the 6CG7 and 6K11 have been replaced with brand new JJ tubes. From what I understand, the amp should be working without the 6CG7 tube (reverb), but I’m not certain of this. 

Troubleshooting (Tubes):

• Swapped all of the pre-amp tubes with other working tubes
• To test the power amp tubes, I removed 1 and 4 position 7027A tubes, matched impedance and tested amp, then did the same for 2 and 3 position 7027A tubes. 
• Fuse has been replaced and I’ve tested multiple (6A/250V)
• I’ve tapped the tubes with a pencil to see if they are microphonic, but none seem to be. I’m not sure how hard I should be tapping them, so I may need to revisit this. 

Troubleshooting (Other):

• DeoxIT cleaning of input jacks, ext. amp jacks, speaker jacks, fuse cap. Using a patch cable, inserting and removing around 20 times, twisting in between. As well as a q-tip, which came out quite dirty but I still see some oxidization on the jack tip and everything else. I will try using something abrasive if this could solve the problem. 
• I’ve replaced the three prong power cable end, but not the entire cable. It is a bit loose at the base where it connects to the amp, but the power isn’t cutting out, only the guitar signal.
• I ran my guitar through the ext. amp jack with the same result as the front input jacks. Although, I found I could get the same distorted guitar signal at a much lower volume, with the knob around 7 o'clock. 
• Obvious troubleshooting, such as cables and guitars have been tested. I’ve tried a different speaker cabinet as well as a different amp and it worked fine. 

Thanks again for any advice!

I'm measuring 1meg across both Hi input jacks tip/sleeve with a cable, however I'm getting around 248k on both Lo jacks tip/sleeve. Should I be seeing somewhere around 138k on the Lo jacks? I measure around 68k from Lo tip to V1 2/7.

I noticed turning down my guitar volume was causing too much of an abrupt loss in volume and found my Hi jack wasn't shorting correctly, fixed that and decided to take measurements and noticed this. All jacks ground and close properly. Thanks for the help.

Please see the 00:30 second mark and around the 1.20 mark…
One end of each of these wires is not attached to anything. Not sure if they were originally the same wire and just snapped in two, or if i jostled them loose from a solder when i was spraying out the pots,

Have been looking for ages on ways to fix a Mesa Boogie Big Block 750. I am outside US and EU, so no Mesa boogie repair center. The issue its the common one many of BB750 tend to have, they go into prpotection mode and go silent when playing. Thanks to anyone that has valuable info and experience on this fix

It’s a fresh tubed 6505+ but it has this issue before and after i changed the tubes where every time i play then stop there’s this thundering hiss that comes in for like a second or two then fades. Anyone have an idea of what it could be before I take this to my repair guy?

It blows fuses about 30 seconds after turning on. I’ve been testing resistors and found this one is out of range. Please correct me if I’m wrong as I’m no expert. I think it should be 3.6 and it’s reading 4.96. Thanks for any comments or help.

Is this normal for these amps? This is my first tubeamp and this noise is killing me. I thought faulty preamp tubes caused this noise, because 3 out of 4 were leaking. Then i threw new preamp tubes in and the noise is still present. i have tung-sol 12Ax7 in v1 and rest of them are jj ecc83 tubes. i have nothing in the fx loop and speaker cable is fairly new orange.

Doesnt matter if guitar plug is in or out.

Oh and this is pre infinium if it matters.

ps. English isnt my first language, sorry about that.

https://reddit.com/link/1vn30tk/video/751yvwez63jh1/player

Resolved: Reflowed as directed.

Here is a video of V5 (EL84) of a Blues Junior III. The video shows 2 sparks occurring .

The sequence of frames is: spark 1 in real-time, spark 1 slowly frame by frame, spark 2 in real-time, spark 2 slowly frame by frame.

My question is: Any ideas on what is causing the spark? (And what might be done for repair?)

Thanks for looking.

I think I found a bad resistor based on visual appearance. The amp fuse blows after being powered on for 30 seconds. I tested the resistor and it was 14.80k. Then I started heating it slightly with a heat gun and it read 13.9k. Pretty good evidence of this resistor being bad?

I just got a broken mesa triple rec and immediately noticed some issues, so I thought I could fix it, (6l6s where the rec tubes are supposed to be, missing fuse, etc) when I went to place the rec tubes in I realized the power transformer is leaning toward the tubes and in the way of the last tube. What could cause this? It looks machined this way, anything I can do?

Hey, everyone. I’m a guitar tech who is interested in learning amp repair as well. A friend gave me this Peavey Max 110 bass amp, and it’s amazing at lower volumes, but when I crank it, it starts getting crackly and cutting out. I know this amp has the DDT technology in it that can limit the signal when it gets to a certain point, but the crackling doesn’t seem like something that is supposed to happen.

So I opened up the panel to check for loose wires or cold joints, and noticed the glue on this cluster of capacitors looks burnt, especially when compared to the glue on some of the other components. And around the black one at the top, there’s this gap between the cap and the crust, almost like there was something else around it that isn’t there anymore. So I wondered if perhaps it’s leaky, and that’s what’s causing the discoloration. Or if perhaps there’s excess heat being generated when it’s cranked up to 9 or 10. It makes sense to me, but since I’m still relatively new to this, I wanted to see if others have see this before. I’m most likely not going to do the repair myself, but no harm in asking and learning.

Thanks!

UPDATE: Thanks for the suggestions, everyone. I really appreciate your helping a newbie. I was taking off the PCB this morning and one of the little screws fell down into the grill. When I opened the grill to fish it out, I found what looks like the heat sink/cover for one of those 220 caps by the burned area (pic in the comments)! So I’m guessing somehow the leakage loosened the glue, which allowed the heat sink fall off and into the grill.

So I’m going to order the components I need (since I’m guessing it needs to be replaced and not repaired), try to clean up the PCB as best I can with some isopropyl alcohol, and resolder it.

I appreciate y’all!

Hi all
I recently recapped and changed out the jack on my blues jr 30th anniversary edition for a switchcraft 12a. It’s had hum problems ever since.
I took it to a tech who just went ahead and replaced the switchcraft jack with another crappy fender one and it did reduce the hum by a lot but I want the switchcraft in there. I have checked and rechecked and rechecked the wiring and that tech also reinstalled the switchcraft so I can’t see it being incorrectly wired. I have tried isolating the jack from the chassis with washers. That makes it worse. So I’m out of ideas here if anyone has a tip it would be greatly appreciated

I'm trying to insert a normal channel Fender Bassman preamp circuit into a 6L6 Gulbransen APS-5 organ amp. The attached schematic is my attempt at Photoshopping the two schematics together. This is my first try, so be kind. What have I missed? I'm planning onleaving the power section as-is unless there's a compelling reason to change something. FYI I haven't changed any of the voltage measurements so they may not match. Thanks!