Dynaco PAT 5 line cord caps/res

[Stevens in SC]

Can someone explain the purpose of C5/C6 to chassis across the ac power
cord of my PAT 5 BIFET? Also, the 56K res across the unswithed ac outlets?
I have a standing 58vac chassis to earth grd, even w/power sw off and the ac line fuse removed. Thks to all for any help, could not load the schematic. Dale

 

[rayma]

Can someone explain the purpose of C5/C6 to chassis across the ac power
cord of my PAT 5 BIFET? Also, the 56K res across the unswithed ac outlets?
I have a standing 58vac chassis to earth grd, even w/power sw off and the ac
line fuse removed.

Those caps are noise filters, and are probably best removed, or replaced with Y rated caps.
The resistor is unusual, and it may be best to remove that as well.
Also check your other components for a similar chassis voltage, just in case.

 

[Stevens in SC]

Rayma, thks for your response; I did all that and the vac went away. Just thought maybe all should check your eg to be sure. Also had a Dyna PAT 4 here and it has no such filtering. Again, thanks for your info. Dale

 

[rayma]

Rayma, thks for your response; I did all that and the vac went away. Just thought
maybe all should check your eg to be sure. Also had a Dyna PAT 4 here and it has
no such filtering. Again, thanks for your info. Dale

Sure, probably those 40 year old caps having 120VAC across them constantly were getting leaky.
I built a fair number of Dynaco PAT-5s at that time, and it took an entire day for each one.

BTW, there's a simple upgrade for the PAT-4 to improve the phono stage. You replace the
electrolytic capacitor C3 (100uF) in each channel with a new one several times larger.

 

[Stevens in SC]

What's the value for "several times larger: ? Dale

 

[rayma]

What's the value for "several times larger: ? Dale

A 470uF would be good.