pas filament supply question

Hello!

I was going to replace the se and filter caps in a pas 3x with diodes, 3300 uf caps using a 4 terminal strip on the chasis stud.

Is an additional dropping resistor usually needed?

.

rmk wrote:Hello!

I was going to replace the se and filter caps in a pas 3x with diodes, 3300 uf caps using a 4 terminal strip on the chasis stud.

Is an additional dropping resistor usually needed?

No.
Filament voltage is on the lower side anyway.

.

Its not clear to me what the voltages should be at a properly working SE. If its not too much trouble, what are the proper voltages at each of the numbered locations?

I do not have the old rectifier.
But according to the manual ( and that corresponds to my memory ) the filament is floating
with the middle of the tubes in PC-6 connected to ground.
The transformer gived 10.5 Volt AC, this is doubled and gives 22Volt DC approximate
around ground. ( tube differences will shift this up and down around ground.)
Note that the caps must be isolated from the chassies and from each other.

.

unrelated question. i replaced the SE today. I noticed the AC wires to the power switch were ran topside. Shouldnt these be on the underside as a twisted pair? (see photo).

rmk wrote:unrelated question. i replaced the SE today. I noticed the AC wires to the power switch were ran topside. Shouldnt these be on the underside as a twisted pair? (see photo).

Yes, they could induce hum at this position, they are very close to the signal(s)
The manual puts them under and close to the side, twinned.

thx, i rerouted it to the underside, twisted along the side. fwiw, it didnt seem to cause hum.

Hopefully the switch and the disc cap is good after reworking.

I took measurements at 117vac line voltage. After replacing the SE (and the can capacitor) the heaters are showing approx 12.1/11.06 vdc for each pair of tubes. Im assuming that is correct.

The can capacitor numbers all seem good.

The only concerning voltage reading was PIN 1 on the plate on each tube on PC6 showing approx 134 vdc (115 vdc is the reference). Is this normal? (Pin 1 on each tube of PC5 was ok at 170vdc).

rmk wrote:I took measurements at 117vac line voltage. After replacing the SE (and the can capacitor) the heaters are showing approx 12.1/11.06 vdc for each pair of tubes. Im assuming that is correct.

The can capacitor numbers all seem good.

The only concerning voltage reading was PIN 1 on the plate on each tube on PC6 showing approx 134 vdc (115 vdc is the reference). Is this normal? (Pin 1 on each tube of PC5 was ok at 170vdc).

The voltages are ok.
The 134Volt vs 115 Volt is due to spread in tube paramaters and not to
be concered about. It could also be to a plate resistor getting bad, you could
check the resistors in place, one connected to pin 1 and eyelet 16 should read
150k, the other is 100k and connected between pin6 on the tube and eyelet 16
( eyley 16 and eyelet 1 are interconnected) If the resistors has drifted
then replace with 1w film resistors. All done with power off and mains
disconnected.

thank you for the tip, those resistors did measure correctly. Have a nice day.

I think the power switch is flakey. I was going to replace it and the .02 snubber. All I have on hand is a double pole switch and .01 safety cap and or a .01 film cap.

Would that value work here?