Guitar Amp Repair | Peavey Transfex Pro

This is a repair of a Peavey Transfex Pro 212s guitar amp. When you turn it on it gets stuck on the start up boot screen and no sound come out of it.
It is a solid state amp but it uses Peavey Transtube technology to sound like a tube amp.
Help me out by giving a Thumbs up and subscribe. Thanks!
#electronicsrepair
#amplifierrepair
#guitaramplifier

[@larrydering1598]

Thanks for tye detailed repair. Those batteries wereca death sentence to a great amp. We used the Profex for pedal steels and only discovered the battery issues after ruining several good processors with acid damage. Ken Fox at vintage electronics repaired tons of them plus offered the replacement chips to do away with the battery. I have a good Profex II and a couple I salvaged with acid damage that need minor trace repairs. They still worked. Best processor for its time.

[@MrBeblis]

Wow, I only build and work on tube amplifiers I would have never been able to pinpoint the issues you found. amazing work 👍

[@NotMarkKnopfler]

Brilliant job - I personally would have re-located the battery somewhere safer and ran cables to it! But brilliant job. Hat's off 👍

[@santiagomoreno696]

Fascinating! really enjoy these videos I hope one day I'm good enough to even understand such circuit, for now all I can do is clean noisy potentiometers and replace some through-hole components

[@rgbplumbinghilton]

Really enjoyed this one. It is satisfying to figure out what had been left by another tech 👍

[@cero815]

Nice! I recommend soldering some wires to the battery and putting it where leakage won't cause (immediate) harm again.

[@CORYSart]

There's a mod to remove the battery permanently with a different chip or something making it battery free

[@signalsandbits]

You can replace the Memory IC with the U637256 memory IC which works with no battery. The problem is the U637256 is no longer made. You may be able to find one on Ali Express but you will pay a high price. Last time I checked the only person that still had these chips available is FoxVintageAmps.com. As of this moment he still sells the upgrade kits for under $40 on his website.

[@cero815]

@@signalsandbits thanks, site under maintenance. Is it simply done by replacing it or will it take some more modfication?

[@noname-gt6vx]

​@@cero815found a transfex wiring diagram and I guess you will have to trick the system to believe finding a fully loaded battery at least. Should be feasible, but I don't know if that is all. Unfortunately I did not find a diagram for the tubefex.

[@noname-gt6vx]

​@@signalsandbitsthanks, but also doubting replacement of the chip would be all. Do you know more details?

[@shawnmarsbar]

I bought one of these amps about 10 years ago, it would power on but the display wouldn't respond and no effects worked. I used it as a power amp with pedals. I opened it up and found the circuit board damaged from battery acid, cut the battery out and cleaned it up. After several failed attempts to fix it I gave up. 5 years later I came across the schematic online and made another attempt. Discovered there were traces completely missing from the acid damage. After spending many hours carefully soldering thin strands of wire between components to replace the missing traces I put it back together, power on and to my surprise everything worked. Still works till this day. I just received a stk 16c88-wf45 memory chip from ebay and gonna do the batteryless mod,hopefully it works.

[@carrielittlecplaster1620]

this amp blew out one of my eardrums!!! Very powerful and ahead of its time. nice work man!! Just got a 95 stereo chorus in mint condition. waiting on a scorpion speaker one was blown. you cant beat the usa peavey stuff.

[@CORYSart]

Wow someone finally did a video of this amp. I have a brand new looking pro head. Ive been holding onto it waiting for the day to fix

[@radegojic4862]

Oh, finally someone that can fix that guitar amp. Great work, I have the same amp, and it is remarkable how I can clearly recognize his sound, I am amazed, and I would like to send you my amp. I have battery leak, it damaged some surrounding components, battery has been replaced, but it doesn't work so now sometimes it works great sometimes it freaks out and tells that sounds is beyond parameters, something like that.

[@signalsandbits]

Email me thanks.

[@calmccullen3539]

Amazing work! Great vid

[@DaveDurango]

I have one that will not turn on. Hasn't for years. Any quick troubleshooting I can try at home? If not, I might like to send it out to you for repair.

[@MrRMWHITE]

How do you repair the digital display? Very dim.

[@noname-gt6vx]

Hi, thanks for your great video. Do you also know the tubefex? Got one with a bit of battery leakage (still NiCd), acid started to get on the nearest resistors. Unit starts up but there is no output :/

[@signalsandbits]

Yes I can. Email me for more info: [e-mail] ~ Thanks

[@noname-gt6vx]

Hey , got another question. Maybe you have an idea. I feel like there is a lot of hiss on overdriven distortion channels of my tubefex. Tubes are original, but should still be "new". Maybe their quality is not too good. Can there be other reasons for hiss one could deal with? When I kill it with built in noise gate, I kill too much. There is no hum at all, so circuit and capacitors should be fine.

[@signalsandbits]

Its tough to tell what that could be. I would swap the tubes and see if the hiss moves to the other channel

[@noname-gt6vx]

@@signalsandbits thank you. Why should the hiss move to another channel and not be reduced or increased?

[@signalsandbits]

Yes you are correct it won't make a difference I would just try different tubes. I assumed you were talking about Channel a vs channel B

[@Route66Wanderer]

Why are you using an isolation transformer when that amp has a power transformer that is already isolating it? Isolation transformer’s are meant for hot chassis’s (Widow Maker’s, that don’t use a power transformer.

[@signalsandbits]

Yes you are correct the xformer in the amp provides isolation. But I dont know what was done by the previous tech so I play it safe in case I have to use my scope.

[@jimmym3361]

You can also replace that memory chip with one that doesn't require a battery. I did this about a year ago. Yank the battery, put in the new chip, reset and done. No more battery worries.

[@signalsandbits]

That was my intention but I couldn't find the chip anywhere for sale. If you know of a source let me know. Thx.

[@terryclemence1599]

Do you still work on amps ?

[@signalsandbits]

yes. if you have something that needs repair you can email me with the details at: [e-mail]

[@CORYSart]

​@@signalsandbitswhat state are you in?

[@signalsandbits]

Illinois

[@terryclemence1599]

@@signalsandbits Im in georgia

[@terryclemence1599]

I have a transfex pro 212s, no power, dunno if its worth fixing, iwill send over some pics