peavey 130 special

[g1]

Yes, those are the ones. Where you have -4.79 should be around -14 or -15V.
One of the chips is probably loading down the voltage. Is U2 getting hot? Any of the other IC's getting hot?
Also check the solder joints on those 5W diodes and resolder if they don't look right.

[bcclew]

i dont feel any heat i am going to pull the circuit board out and look on other side i had it out once maybe i missed something ill get back tomorrow thanks

[bcclew]

i dont feel any heat i am going to pull the circuit board out and look on other side i had it out once maybe i missed something ill get back tomorrow thanks

ok took board out to look at other side.i have a good magnifying light all soldering looks good. i cked all the circuit tracks on board with dvom all were complete none broke or high resistance.i am still trying to get a handle on cr36&37 so when i put back i can try to re ck for that 15 volts

[bcclew]

i didnt mention i changed all the ics i got them from peavey. and did index them like dia shows i did this about 4 years ago. never got back until now.

[bcclew]

i didnt mention i changed all the ics i got them from peavey. and did index them like dia shows i did this about 4 years ago. never got back until now.

ok back again i got it cr36 has 13.66 on one side and 1.495 on other cr37 has -4.80 on one side and 1.495 on the other i found a dia of the other side of the board now i can see thanks

[Enzo]

Um... where are you grounding your meter for these readings? CR36,37 are zeners regulating the 15v supplies, and as such have one end grounded. But you have a volt and a half on what I presume is the ground end of both of them. Are all the board screws in placce holding the board into the chassis?

Have we replaced CR37 yet?

The ICs are in sockets, yes? Pull all four and power up, is the -15 still way low?

CR36,37 are diodes, and look like litle cyliners with a stripe. Each has a 5 watt resistor associated, R97,98. 250 ohms, do they measure right at power off?

[bcclew]

putting black lead of volt meter on chassis had 4 screws back for this test. will put them all back and ck again. ill be back monday after 2pm ill ck with ics out thanks for all your help

[bcclew]

also if i replace cr37 what am i asking for

[Enzo]

plain old 15v 1 watt zener diode, most commonly 1N4744. The 40102 is a Peavey house number.

[bcclew]

plain old 15v 1 watt zener diode, most commonly 1N4744. The 40102 is a Peavey house number.

Heading to raido shack get a diode also on sciatic it say voltage should be cked with switch closed not sure if I did that .what you think?

[bcclew]

plain old 15v 1 watt zener diode, most commonly 1N4744. The 40102 is a Peavey house number.

ok back again cked vlotage with ics out on cr37 voltage went from 4.79 to 3.61.i got a new diode this number nti electronics zener diode nte 145a 15.0 vlots +5% pd 1W THIS IS BLACK WITH A SILVER STRIPE IF THATS RIGHT SHOULD I CHANGE IT?AND DOES THE STRIPE FACE THE 4.79 SIDE OR THE 1.495 SIDE

[g1]

Stripe should go where you had 1.495

[Enzo]

Stripe should go where the stripe was on the original part. Also, the parts layour drawing with the schematic shows parts orientations.

I am betting on that zener, but do the tests with the ICs out. If the voltage remains low, putting the ICs back in wonlt raise it. We need to solve teh low voltage before the ICs return.

[bcclew]

Put diode in got -17.31 where we had 4.80 ic pin 8 13.64 pin 4 17.31 went to pin 7 had -1.347 clicking switch -0.752 also when clicking switch i hear a slight pop in speaker

[bcclew]

i did test with ics in do you want me to take them out? ill do it tomorrow 9.25 pm heading home thanks