Need Help with Linear Power 3.2HV

[Itsme]

hello, i have a Linear Power amp that isn't working. I am pretty sure the power supply is working, but no output.
Any advice would be greatly appreciatted.

[Perry Babin]

You need to confirm that the power supply is working. Measure the voltage on the output transistors. With your meter set to DC volts and the amp powered up, measure the voltage from the case of an MJ15022 to the case of an MJ15023. If you get no voltage, go to the mounting screws for the transistors.

How much voltage is there across the transistors?

[Itsme]

Originally posted by Perry Babin
You need to confirm that the power supply is working. Measure the voltage on the output transistors. With your meter set to DC volts and the amp powered up, measure the voltage from the case of an MJ15022 to the case of an MJ15023. If you get no voltage, go to the mounting screws for the transistors.

How much voltage is there across the transistors?

I'm not getting any voltage from the 022 to the 023's and nothing from them to the m screws of the 2n5302's. But I do get 12.8 volts from B- to 2n5302 cases. Hope that helps?

[Perry Babin]

If the power supply IC is an SG3526, is there ~12v on pin 17?

Look up the datasheet if you don't know how the pins are numbered.
http://www.onsemi.com/pub_link/Collateral/SG3526-D.PDF

[Itsme]

Originally posted by Perry Babin
If the power supply IC is an SG3526, is there ~12v on pin 17?

Look up the datasheet if you don't know how the pins are numbered.
http://www.onsemi.com/pub_link/Collateral/SG3526-D.PDF

No voltage from B- to pin 17

[Perry Babin]

Measure the DC voltage on pins 1, 2, 3 and 8 of the 555 timer IC.

http://www.national.com/images/pf/LM555/00785103.pdf

[Itsme]

Originally posted by Perry Babin
Measure the DC voltage on pins 1, 2, 3 and 8 of the 555 timer IC.

http://www.national.com/images/pf/LM555/00785103.pdf

I think mine is a MC1455P1
http://www.onsemi.com/pub_link/Collateral/MC1455-D.PDF

Anyway i measured it.
1.) 0
2.) 12.43
3.) 11.69
8.) 12.37

[Perry Babin]

Pin 3 should be near ground. When you apply remote voltage, does the voltage on pin 6 begin to rise slowly?

Post the voltage for the rest of the pins on the 555.

[Itsme]

Originally posted by Perry Babin
Pin 3 should be near ground. When you apply remote voltage, does the voltage on pin 6 begin to rise slowly?

Post the voltage for the rest of the pins on the 555.

I don't see a 555 timer on the board. i have been measuring from a MC1455P1 timer. I hope this is right??? Anyway pin 6 with no power is 0.60 and then goes to 0 (grounds) No voltage when amp is on.

1.) 0
2.) 12.43
3.)11.72
4.) 12.35
5.) 1.30
6.) 0
7.) 0
8.) 12.36

http://www.onsemi.com/pub_link/Collateral/MC1455-D.PDF

Here is the data sheet for the MC1455P1......

[Perry Babin]

That IC is the same as the 555.

When you apply remote voltage, does the voltage on pin 6 slowly rise to ~2/3 of the voltage on pin 8 then drop back to 0v?

If not, there may be a defective capacitor between pin 6 and ground.