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Messages - pontiacpete

Do you mean the tweeter and woofer? Just realizing this now, the tweeter control is not doing anything. That is, there is no sound when the woofer pot is turned down all the way. The distortion is in the woofer only
sorry I dropped out for a while, had to get away and the of course a bunch of amps came in.
Also sorry about the confusion with the schematics. The first one I posted, I thought was the C version of the board. When I realized this wasn't that at all GK help location the correct on. Obviously it's a photo of the original.
There is no DC on the output and I check connections on the LM3886. Thought I might have messed up something there but it looks good. There is the possibility that the chip is not go, I suppose.
So when I plug into the effects return with the boost down it is the same level of distortion as in the input. The cap that blew up was definitely not a Non-polarized cap. I still have the casing which shows the polarity.
yes, it's distorting in both hi and low amp. I have tried to turn R9 but change in sound.
Q6 is the circuit near the LM555 and it is shorted by J1. Is this the fault circuit? What is J1? I can't seem to find out where that is. ANyway,The cap that blew up c21 is on pin 8 of the LM3886 which was smoking and then replaced. This could be difficult to repair. There are parts on this schematic that I can't find on the board and there are parts added that aren't part of the PCB, that is, with a designated location. I suppose because this is an early model and it never made it to the service manual.
Finally got the correct schematic.
The pin out of the MPSA06 is EBC, it's also written on the board but the schematic clearly says Q6 is the 2SC3478, confusing.
When this amp came to me I plugged it in and it made sound but soon started to smoke and then an electrolytic cap blew, C21 10uf/50v.You cannot view this attachment.

Also the LM3886 chip was smoking and had burn marks under the legs. I replaced both the cap and the LM3886. The amp is making sound but it is distorted. So far I check all the transistors under the heat sink for any shorts in circuit. All of them seem to be ok. I pulled Q6 which was reading a dead short between B-E but out of circuit it measures to be good. Q6 is a MPSA06 but on the schematic I have from GK says it's an 2SC3478. Confusing to me. THe trim pot R9 is not changing the distorted sound. Any ideas where I should go from here? Thanks!
Amplifier Discussion / Re: help w/ peavey TNT 150
January 14, 2011, 05:26:42 PM
found an open trace where R65 , the crossover frequ.  pot was installed.  Thanks for the help.

Amplifier Discussion / Re: help w/ peavey TNT 150
January 14, 2011, 04:27:41 PM
I changed the regulators vr1/2.  Now it is running -/+15v,  don't know why it isn't -/+16v. But it'ssStill scratchy.  I trace this neg voltage to the neg side of C26 and the voltage R49.  ON the other side of r49 there's -2.5v which is the same as that on U9B pin5 and 6.  PIn 7 of U10B has -10v.  Should there be -10v on pin7 of U10? Should there be negative voltage in pin 6 of U9?  I each of these IC, and the resistors seem to being what they're suppose to be doing, dropping voltage.  
Is it possible that it's ok to have negative voltage on a pot?  Are the new pots that I've put in possibly be bad?
I'm stumped.
Amplifier Discussion / Re: help w/ peavey TNT 150
January 14, 2011, 02:29:15 PM
here it is
Amplifier Discussion / Re: help w/ peavey TNT 150
January 14, 2011, 11:24:50 AM
I think there are a couple of regulars of some sort that are not working properly,  there are vr1/2.
What do you think?  I changed cr21 cr25 also and I swapped in new c21 and c22
Amplifier Discussion / Re: help w/ peavey TNT 150
January 14, 2011, 10:15:15 AM
It's not allowing me to post a 926KB schematic.  Is that all that's allowed or is there something I'm missing here?
Amplifier Discussion / Re: help w/ peavey TNT 150
January 14, 2011, 09:57:34 AM
How can I post a schematic,  it's the 512kB?
Amplifier Discussion / Re: help w/ peavey TNT 150
January 14, 2011, 09:03:42 AM
the 'post' pot.  I'll will be putting up the schematic soon. 

I've tried everything here.  The only peculiar thing other than almost a -1v on the pot is the voltage on the IC directly above the pot.  It has -15 on pin 8 and 16v on pin 5.
Amplifier Discussion / help w/ peavey TNT 150
January 14, 2011, 06:38:53 AM
This amp has a scratchy post pot. I replaced the pot and swapped out all the electrolytics in the area and the nearest ICs, checked resistors and changed the one .1uf cap closer to the input. At the moment I don't have a schematic, but I hope to have it by tomorrow morning. There is negative voltage on the pot as it is increased up to about -.9vdc. On a light limiter the light jumps up brighter as the pot is turned.

Does anyone have any advice?
Thanks in advance.