Did I fry my output transformer?

[theculprit]

Just found this too. From back in February (which would be less than eight months ago, not a year). And apparently theculprit DID try the Peavey after the incident. Either they don't remember that or chose to lie about it for some reason. Either way we shouldn't expect honest or accurate reporting from this member. Which means we can't help. They need a tech.

https://www.rig-talk.com/forum/threa...rew-up.298562/

Contemporary with this MEF thread on another forum he was asked to plug into the effects loop (or just jumper the effects loop) and experienced loud squealing feedback.

Reading through the other forums and this earlier one I think it's likely cruddy contacts that need cleaning. With loud feedback I don't suspect the OT or even the flyback diodes. Unless diodes can fail intermittently. Which they may but I've never seen it.

That is in fact my post, but there is no reason for me to be dishonest about anything here and you are right in that I am just as forgetful as I am clumsy. I did test it in February and that is when I initially realized there was something wrong with the amp after not turning it on since I got the Randall. The reason why I didn't mentioned it here is because I didn't want to give you guys any redundant or useless information as I'm pretty good at doing lol

As far as the effects loop goes, the first time I tried to plug into the return I got a screeching sound, but I now realize that it was likely caused by a bad output jack in the guitar I used. I tested it again with another guitar and I was able to get a clean signal from the effect return but it was quiet as others mentioned.

Jumpering provided the same results as plugging it just into the front of the amp. Low signal.

[theculprit]

Hmm. Maybe the OP was looking for an easier answer.

The internet seems to have popularized the idea that for technical issues, there is probably a quick and dirty trick for fixing things. Youtube has reams of videos on doing "hacks" of nearly everything, from cooking, to construction, to tools, to life in general, even medicine (!!!). All have the underlying idea that there is a quick, easy trick to just cut through needing to know or understand some situation, sidestepping that difficult study and practice to achieve expertise. It's a riff on the idea that all specialists are taking advantage of you and overcharging you, combined with some good old Dunning Kruger.

Dunning-Kruger is pernicious. It's the idea that people who know the least about some issue are also the ones who lack the knowledge to understand how much they don't know about the topic.
https://www.linkedin.com/pulse/chatg...yman-a-quraini
Maybe people need to watch Disney's 1940 section of Fantasia, "The Sorcerer's Apprentice" more.

I am really not looking for a quick fix or any type of hack and I definitely don't want to take credit from anyone who's done their fair share. As I mentioned before I figured I'd try and learn from this and hopefully get a better idea of what/why this is happening. I am new to electronics, but I know how to use a soldering iron and have put some stuff together following some guides. I can differentiate between different components and have an idea of what they do, but I sure as hell couldn’t tell you how to build an amp. I was hoping you all could just point me in the right direction and I would do my own research.

So far everywhere I've asked, everyone immediately points to the tubes, but nobody has been able to give me any information really beyond that until I found this forum. Reading your responses helped me a lot and I really do appreciate you all taking the time. You guys definitely know your stuff, and I’m sorry if I offended anyone..

Thanks again fellas

[Delta362]

I suspect the transient switching circuit. My first guess would be that Q2 (J174) is shorted. I had a similar issue with a 5150 II recently. Volume was very low, even injecting the signal into the effects loop return.

[Chuck H]

As far as the effects loop goes, the first time I tried to plug into the return I got a screeching sound, but I now realize that it was likely caused by a bad output jack in the guitar I used.

Not likely. Even an open circuit at the effects return isn't likely to cause loud screeching. It's more likely there was a problem at the jack itself. Not a problem WITH it, but AT it. It's a switching jack and may need to be cleaned. Sometimes a dirty switching jack will work temporarily just by plugging and unplugging a few times. As would be the case when you were testing this. You mentioned at the other forum that it was loud enough to potentially disturb neighbors. This makes it very unlikely your OT is compromised.

I tested it again with another guitar and I was able to get a clean signal from the effect return but it was quiet as others mentioned.

This is to be expected because your guitar has very little output compared to what the amplifier circuit has at this point in the circuit. Less signal amplified means less signal at the output.

Jumpering provided the same results as plugging it just into the front of the amp. Low signal.

I expect that by this time the effects loop jacks were operating because of your plugging in and out of them. So if the problem lies elsewhere then with the effects loop jumpered your results would be the same as if it weren't because the effects loop actually jumpers itself via jack switches when it is unplugged. So it would seem your problem is elsewhere.

One thing your test do seem to reveal is that your problem is in the preamp and NOT the power amp circuit of your amp. Nothing about plugging the Randall into the Peavey's output should affect the Peavey's preamp in any way. So the problem with your Peavey coming up analogous to plugging the Randall into it would seem to be a coincidence. But not related to your problem.

I still think that going through the Peavey and cleaning all non soldered contacts is a good place to start. Tube sockets, ribbon conections, pots and jack switches. There are specific methods and products to do some of this work to avoid damage. Your tech should be able to do it for a reasonable price. And if that doesn't solve your problem this is important maintenance anyway. And your tech would have the amp on hand and open for diagnosis.