09-06-2016, 08:38 PM
Hi Greg,
It's ur other pair of eyes. #73, Capacitance isn't very critical I used 4.7mf @450v. You can mount the replacements (4) under the chassis or cut the can and install them inside. The important thing is to be sure the old ones disconnected. + goes to the terminals - to the chassis.
#90 (8mf @450v) a 10mf is fine too + goes to the 80 filament - to the power transformer HV center tap.
#91 has two caps inside an 8mf (or or 10mf @450v) + goes to the filter choke - to the tap. The 10mf (@50v or so) the + side goes to the chassis and - to the tap. It filters the negative bias voltage for the audio stages.
Don't power it up without the spkr plugged in. Monitor the HV at the 80 filament to the chassis. If the power supply is working well and have no shorts should see about 350vdc. If you are at 250v or less you've still got a problem. You may notice plates of the 80 glowing a dull red, not good indicates a short in the HV.
GL
Terry
It's ur other pair of eyes. #73, Capacitance isn't very critical I used 4.7mf @450v. You can mount the replacements (4) under the chassis or cut the can and install them inside. The important thing is to be sure the old ones disconnected. + goes to the terminals - to the chassis.
#90 (8mf @450v) a 10mf is fine too + goes to the 80 filament - to the power transformer HV center tap.
#91 has two caps inside an 8mf (or or 10mf @450v) + goes to the filter choke - to the tap. The 10mf (@50v or so) the + side goes to the chassis and - to the tap. It filters the negative bias voltage for the audio stages.
Don't power it up without the spkr plugged in. Monitor the HV at the 80 filament to the chassis. If the power supply is working well and have no shorts should see about 350vdc. If you are at 250v or less you've still got a problem. You may notice plates of the 80 glowing a dull red, not good indicates a short in the HV.
GL
Terry
When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!
Terry
