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Post by JFrankParnell on Apr 11, 2016 0:20:17 GMT -5
 I tried taking out those 4 screws, on the top, and the chassis definitely was disconnected from the top, but it didnt feel like it wanted to pull out. So, the reason I was doing that is there is a metallic buzz or resonance , at high volumes. When the amp is off, and you jostle it around, you can hear something clanging around in there. Not really like a reverb spring, more like just one clank. And that clank sounds to me like the same tone as the buzz that it makes. Anyway, I thought if I could get the guts out of the box, I could figure out what is buzzing and clanging. Also, this thing has a loud pop, when you turn the power off. You guys surely know the fix for this. Furthermore  this amp has a ground loop hum, like almost everything else, in my room, unless you disable the ground (like the other humming things). But the weird thing is, I have a Peavey TKO75 sitting right next to it and plugged into the same power strip and that amp never hums. |
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Post by JFrankParnell on Apr 12, 2016 23:54:38 GMT -5
It turns out, you have to take out 4 little screws on the back plate, as well, because the front and the back are actually connected, albeit kinda loosely. And then the whole thing comes out the back, but you gotta worry it past the tolex, on the box.
It didnt seem like anything in there was the problem, although now I'm re-wondering that. Because, I wound up taking out the speaker and removing the reverb tank. Easy enough, but it didnt solve the problem with the clank/buzz.
I'm going to try again taking the chassis out, because i guess it's got to be that flaky connection between the front and the back, that is resonating at higher volumes. I guess it could also be the horn, which would be pretty easy to take out as well.
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Post by sumgai on Apr 13, 2016 11:17:33 GMT -5
JFP,
Sorry, been busy the past several days, and missed your posting when it first went up.
Yes, there are more than a few screws to remove, on most Peavey amps, in order to get the chassis out. The idea being, I presume, that it would be nice to not have to worry about rattles, bangs, klunks, buzzes, and other vibratory noises. Worked most of the time, but in your case.... 
I have serviced probably a dozen of these particular models, and plenty more Peavey combos made like this one with different nameplates, but essentially the same thing. What usually goes haywire is either a screw has come loose (perhaps one of those that goes into the wood, and has become stripped), or the nut fell off, etc. In all my time, I've never seen the reverb tank come loose from its moorings, but I have seen a cable (in fact, both of them) come loose, but you said that that setup is fine.
BTW, when you put this back together, take care to clear the speaker wire so that it doesn't get pinched between the chassis and the box. I once saw this happen, one of the two wires being nearly severed because the owner was in a hurry, or maybe he was "on something" at the time, I dunno... but you get the point. Pulling the speaker itself is a good idea to avoid that kind of issue, although it's more work, to be sure.
As to the horn, those things are like $10 USD, they are Cheap with a capital c, trust me. Testing is easy of course, and you should be able to find a replacement in all the usual haunts. Pay attention to model numbers - don't buy an cheap one for more money, thinking that more expensive must be more quality. The reality is, most of these can handle lots of watts, but they suck in the fidelity department. For a really good one, you might have to go to a hi-fi house and pay big bucks. Probably not worth it, in most people's opinion, but this is your amp, not theirs.
The cross-over network is really just a capacitor, I doubt there's an inductor in there too. On another brand of amp, I once saw that the cap had come unsoldered, and was literally bouncing off the terminal, and back on again, to make intermittent contact. That was fun to find! 
Inside the amp, specifically the chassis, I'd take a magnifying glass to the circuit board, and look for bad solder joints. If in doubt, re-heat every last one of 'em. In fact, I procured my current Fender Bassman 200 for almighty cheap dollars, because the filter caps in the power supply had not been soldered correctly - the amp cut in and out. The previous owner no longer had any confidence in it, so I picked it up for a song and a dance.
I think you know how to look for loose stuff, so I'll leave that to you. I'm pretty sure you've got the basics down, so let us know if it was simple, or if there's still a problem, eh? 
HTH
sumgai
p.s. I've moved to Monroe. Easier to find my new place, but it's not any closer to you - sorry!  |
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Post by JFrankParnell on Apr 13, 2016 21:26:35 GMT -5
Hey Sumgai, I think it's the quilt show, in Anacortes, this weekend? Give me a buzz, if youre around; I'll be pretty busy cuz I'm playin a show, on Saturday, but you might like to show up, for that. I'm playing bass, in The Mosstones.  |
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Post by JFrankParnell on Apr 25, 2016 9:45:26 GMT -5
Well, hell...
After I pulled the horn (which didnt make much diff), I pulled the chassis, again and attempted to play thru it. The buzz was still present, even with the chassis out of the box. I started messing with the volume knob, turning it up quite a bit...started to get some bad sounds, some cut-outs... and then a some spluttering and now it's almost completely dead. It still plays at very very faint volume, but it's fucked. I guess I blew something, maybe something that was already almost blown, i dont know.
Sumgai, I'm going to take it to Garytronics, in Stanwood, unless maybe you know a guy in Bellingham? I'm in Bham, often. Monroe is about twice as far as either of those...
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Post by sumgai on Apr 25, 2016 23:46:49 GMT -5
JFrank,
That feller in Standwood has always had good recommendations, as far as I've ever heard. Don't know anyone in B'ham, sorry.
And doesn't Helmer Music have anyone on tap for this kinda thing?
Good luck!
sumgai
p.s. Sorry I didn't get up there two weeks ago, we got sucked into a local RV show. Almost committed to a one-way ticket to Suckers-ville, but escaped at the last moment. Not going there again anytime too soon.... How was your show, did anyone record any of it? |
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Post by JFrankParnell on Apr 27, 2016 8:57:36 GMT -5
It was fun! Gettin psyched for another show, this weekend.
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this amp has a ground loop hum, like almost everything else, in my room, unless you disable the ground (like the other humming things). But the weird thing is, I have a Peavey TKO75 sitting right next to it and plugged into the same power strip and that amp never hums.
