Hi All,
Hammond tech support came through, the replacement power trans arrived this week. Got it all wired up. No load voltages look too high. With my trusty 250 watt light bulb current limiter, measured some voltages.
Note: I do have the Immortal Mod's ss rectifiers installed on pin 7 to 6 and pin 5 to 4 on the rectifier socket. I have the hv wires going to pin 7 and pin 5. I checked with the "diode check" setting on my cheapo meter and they read OK, not shorted, not open.
Line voltage: reading 122vac.
With power off, and circuit all wired up (filter caps drained)
Read 174 ohms across the choke, but this is with it wired in to the circuit. Can't tell whether this is useful info.
Powered up, power switch on, standby off (doesn't matter since no rectifier)
Without the rectifier tube installed:
At the rectifier socket:
pin 2 to 8 5vac
pin 7 to pin 5 717vac
Across green wires 6.3v
Look OK.
Powered down, plugged in the rectifier tube, powered up OK, no smoke no sparks.
At the rectifier socket:
pin 6 to ground 356vac
pin 4 to ground 356vac (this is the circuit side of the SS rectifiers)
standby OFF:
pin 8 to ground 489vdc Eeek!
Standby ON:
pin 8 to ground 488vdc
With standby on, getting about same voltage downside of choke.
OUCH my filter caps are only rated 475v!!! (They are F&T 16uf 475v)
Powered down, drained all filter caps.
The Fender schematic reads 420 to 410 vdc on sides of the choke.
Questions:
Did I toast the filter caps?
Do I need to swap out for 500v filter caps?
Will the B+ voltages drop to values closer to what the schematic reads after powering up with all of the other tubes installed and the speaker hooked up?
Thanks.
Hammond tech support came through, the replacement power trans arrived this week. Got it all wired up. No load voltages look too high. With my trusty 250 watt light bulb current limiter, measured some voltages.
Note: I do have the Immortal Mod's ss rectifiers installed on pin 7 to 6 and pin 5 to 4 on the rectifier socket. I have the hv wires going to pin 7 and pin 5. I checked with the "diode check" setting on my cheapo meter and they read OK, not shorted, not open.
Line voltage: reading 122vac.
With power off, and circuit all wired up (filter caps drained)
Read 174 ohms across the choke, but this is with it wired in to the circuit. Can't tell whether this is useful info.
Powered up, power switch on, standby off (doesn't matter since no rectifier)
Without the rectifier tube installed:
At the rectifier socket:
pin 2 to 8 5vac
pin 7 to pin 5 717vac
Across green wires 6.3v
Look OK.
Powered down, plugged in the rectifier tube, powered up OK, no smoke no sparks.
At the rectifier socket:
pin 6 to ground 356vac
pin 4 to ground 356vac (this is the circuit side of the SS rectifiers)
standby OFF:
pin 8 to ground 489vdc Eeek!
Standby ON:
pin 8 to ground 488vdc
With standby on, getting about same voltage downside of choke.
OUCH my filter caps are only rated 475v!!! (They are F&T 16uf 475v)
Powered down, drained all filter caps.
The Fender schematic reads 420 to 410 vdc on sides of the choke.
Questions:
Did I toast the filter caps?
Do I need to swap out for 500v filter caps?
Will the B+ voltages drop to values closer to what the schematic reads after powering up with all of the other tubes installed and the speaker hooked up?
Thanks.
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