peavey 130 special

[Enzo]

I saw that and was not convinced it hit ground, but you may be right, I see no other place, and I usually can follow the complex PV ground schemes.

[bcclew]

if i take the screws out and lift it off .and see if the voltage changes? then ican pull board back off and ck other side?let me know thanks

[Enzo]

We have 47 ohms instead of close to zero ohms. Use that rather than voltages.

[bcclew]

ok i get to work ipm monday yill ck and get back thanks

[bcclew]

re130

ok i get to work ipm monday yill ck and get back thanks

took thermal breaker off still 47 ohms pushed board down slightly no change in readings. screws are only about 3 threads on a machine screw. dos!ent look like it goes all the through.i can pull board off chassis if you want and look from the other side? let me no thanks

[bcclew]

where are the posts about the thermal switch? any way this what i did took thermal breaker off still 47 ohms pushed board down slightly no change in readings. screws are only about 3 threads on a machine screw. dos!ent look like it goes all the through.i can pull board off chassis if you want and look from the other side? let me no thanks

[g1]

I have outlined the ground trace in red. The mounting bolt for the thermal switch should connect that trace to the heatsink. You should be able to see the trace from the bottom of the board.
At the bottom of the picture is a wire jumper marked J. Check it's solder joints. Either the mounting bolt or the wire jumper must have a bad connection, or there is a burnt or cracked trace. Also the heatsink should measure 0 ohms to the chassis.

[bcclew]

ok its 930 ill get it tomorrow about 2pm thanks

[bcclew]

ok back one thing i should have said is.this amp has been worked on before there are pencil marks on the board.looking at the dia it shows the thermal breaker with nuts on top meaning bolts come up from inside.when i took it off these bolts were different sizes.now with the board off chassis i can see the hole going to the trace. these screws wouldnt be long enough to reach the trace so i would say that ground was never hooked up since i have had the amp. now heatsink are we talking about the ribbed piece on back? if so that is 0.5 to chassis.let me no if i should put bolt up the other side with a nut on breaker?gi i think you got it ,thanks as always

[g1]

Doesn't the thermal breaker sit on a piece of metal that the output transistors are mounted on? That is the heatsink.
Yes, a bolt up from under with a nut should be used. If you can post any pictures that would help.

[bcclew]

ok got the metal that holds the thermal breaker is the same as transistors mounting.geting pics done right now a little hard but ill try later.early on i said i did auto dc.a bad ground in a headlight cir.it will try too steal it from another cir. is that whats happening here? just curious thanks ill put bolt in and ck ohms

[Enzo]

Have we been taking these readings with the heat sink not bolted to the chassis???

[bcclew]

Doesn't the thermal breaker sit on a piece of metal that the output transistors are mounted on? That is the heatsink.
Yes, a bolt up from under with a nut should be used. If you can post any pictures that would help.

ok got the metal that holds the thermal breaker is the same as transistors mounting.geting pics done right now a little hard but ill try later.early on i said i did auto dc.a bad ground in a headlight cir.it will try too steal it from another cir. is that whats happening here? just curious thanks ill put bolt in and ck ohms

[bcclew]

ok put bolt in and back in chassis reading is 000.3 ohms to cr37 no more 47 ohms what next?

[g1]

Check that when running there is now 0 volts there instead of the 1.4V you had there before.
Then you should be good to go.
You had asked some time ago what problem would be caused because that point (common ground) was not 0 Volts. It would probably cause ground hum.