ampeg v-4 restoration project

[geertjacobs]

PL = Pilot Light
Could you draw how the wirewound resistor is connected to the circuit?

[michael_krell]

thanks for the fast response. one end of it goes to the center tap of the primary on the output tranny and the other side of it goes to one side of R54. the 100k resistor before the PL.

which apparantly means pilto light.

[geertjacobs]

Isn't the white resistor R55? That's specified as a 7W resistor.

[michael_krell]

no, thats a different resistor that is on the board. the big white wire wound one is 91 ohm

[michael_krell]

Does anyone know what this large resistor mounted on the outside of the chasis is for. It currently goes to the center tap of the output transformer. Its 91 ohm. Is this possibly a current limiter that is not shown in the schematic???

[michael_krell]

Alright so forget everything i said before. basically i am getting 800 volts after the bridge rectifier. i really do not know why. am i just measuring something wrong?

[michael_krell]

SUCCESS, well, i didnt die, and this old ampeg is working. Thank you for all your help. Turns out it was a short between the HV and the primary windings of the power tran. Also some shotty wiring and bad filter caps. But overall this puppy runs great. I may get some new power tubes. Maybe get some 7027A's and rebias it. But right now its pretty cool.