I bought this amp used and after a few weeks it suddenly began to cut out at high volumes. So I've suspected that there is something loose inside because when I tap the sides it cuts out. Doing research online I've found that it could possibly be a loose transistor so I got my soldering iron and re heated all the transistors and now it is making a pop when I turn it on and the original problem still exists.The board also had a lot of yellow corrosion here and there, I cleaned that before I re heated the transistors. What else can I try? Should I take the transistors out and put them back in or just replace them?
Hi
First, this belongs down in the instrument amp section, and they will probably move it, so if you come back and it is gone, look down there.
You need to be systematic, as it stands you are just guessing.
frankly, "loose transistor" is way down my list of suspects. But I agree it is a loose connections somewhere if tapping on it makes a change. The amp works, at least part time, so I doubt you have a bad transistor. Bad transistors don't respond to tapping.
Please specify the model amp. Otherwise I cannot point you to specific places in it. But if you have an FX loop in the amp, then plug a spare cord from FX send to FX return. ANy help? Or if the amp has a pair of jacks - preamp out and power amp in, plug a cord from pre out to power amp in. ANy help?
I suspect your yellow corrosion was just residue from the manufacture process and not likely harmful. But no harm in cleaning it off either.
A speaker cutting out or speaker wiring comes to mind, but if tapping on the amp stops it, then I think the speaker is not the issue.
ANy part in it could be loose, no need to limit things to transistors. Since you are happy soldering, open the amp, connect a speaker, apply a signal and dig in. I just use a feed from my bench stereo receiver, but a CD player or something would work. A guitar would work, but then you have your hands tied up.
Get a wooden chopstick like from a Chinese restaurant, or some other insulated thing, and while the amp is running, go along the board and poke each part, looking to find parts that react. Larger parts are more likely, like larger transistors or 5w or 10w resistors, or large caps. But really any part can get loose. And don't overlook the connectors where wires and cables plug onto the board. And ribbon cables between subassemblies. Flex those.
The key is to isolate the problem. Once we know where it is, it is usually simple to correct what it is.
First, this belongs down in the instrument amp section, and they will probably move it, so if you come back and it is gone, look down there.
You need to be systematic, as it stands you are just guessing.
frankly, "loose transistor" is way down my list of suspects. But I agree it is a loose connections somewhere if tapping on it makes a change. The amp works, at least part time, so I doubt you have a bad transistor. Bad transistors don't respond to tapping.
Please specify the model amp. Otherwise I cannot point you to specific places in it. But if you have an FX loop in the amp, then plug a spare cord from FX send to FX return. ANy help? Or if the amp has a pair of jacks - preamp out and power amp in, plug a cord from pre out to power amp in. ANy help?
I suspect your yellow corrosion was just residue from the manufacture process and not likely harmful. But no harm in cleaning it off either.
A speaker cutting out or speaker wiring comes to mind, but if tapping on the amp stops it, then I think the speaker is not the issue.
ANy part in it could be loose, no need to limit things to transistors. Since you are happy soldering, open the amp, connect a speaker, apply a signal and dig in. I just use a feed from my bench stereo receiver, but a CD player or something would work. A guitar would work, but then you have your hands tied up.
Get a wooden chopstick like from a Chinese restaurant, or some other insulated thing, and while the amp is running, go along the board and poke each part, looking to find parts that react. Larger parts are more likely, like larger transistors or 5w or 10w resistors, or large caps. But really any part can get loose. And don't overlook the connectors where wires and cables plug onto the board. And ribbon cables between subassemblies. Flex those.
The key is to isolate the problem. Once we know where it is, it is usually simple to correct what it is.
try to check send/return sockets, sometimes the switch inside them fails or needs to clean. Sometimes is enough to stick the jack to them then very quick pull😉 and the switch is on😀
🙄my guess: electrolyte from leakage capacitors? try to check the biggest caps if not barreled/swollen, if yes replace.
I would not touch the outout trannies if amp works from time to time🙂
Threads merged, would have been great if one of y'all had thought to report the duplicate thread. Merged thread cleaned up for readability. Please feel free to repost any information that might have been lost during the merge.
Wow thanks for the quick replies. I will look into all of that later and be back with my results.
Also sorry about the duplicate I couldnt figure out how to delete the post in solid states
Also sorry about the duplicate I couldnt figure out how to delete the post in solid states
I havn't had time to work on the amp yet but the amp is a Peavey Transtube 212 EFX it has 4 boards all together.
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