Welcome Guest! Be sure you know and follow the Phorum Rules before posting. Thank you and Enjoy! (January 12, 2025) x


Bad 35c5 in 60's Zenith K725 killed the FM?
#3

I am not looking at one of these right now, but generically, check the spring and ball bearing that forms the detent, and check the holes for the detent. If the holes have rusted or worn to the point the ball gets caught in them, try a bigger ball bearing. Clean the detent and lube with automotive wheel bearing grease. This may help.

The 35C5 killing FM but not AM is a funky issue. Looking at the schematic, if the grid leakage caused either excess screen or plate current, it could load down the supply to the limiter, but it would also load down the IF stages that involve both AM and FM.

"Do Justly, love Mercy and walk humbly with your God"- Micah 6:8
"Let us begin to do good"- St. Francis

Best Regards, 

MrFixr55


Messages In This Thread
RE: Bad 35c5 in 60's Zenith K725 killed the FM? - by MrFixr55 - 08-13-2026, 09:23 PM



Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
Philco 71 Code 125
Ok guys. Thanks for the input. As for AI this is why I ask the experts. Dandconant — 07:39 AM
Philco 71 Code 125
Technically, that's C-. B- is chassis ground. The resistor between chassis ground and the HV center tap makes the HV c...MrFixr55 — 11:24 PM
54C Cabinet Refinish
hello Roy, I’d follow Arran’s suggestion and use automotive gasket material, which I keep around for situations like th...radiorich — 10:22 PM
Philco 71 Code 125
This might be one of those cases where it's a ground to an AC voltage and B- to DC.RodB — 08:22 PM
Philco 71 Code 125
Really Rod? I know you would not steer me wrong but AI say this is a short circuit? What if I moved the 6 volt center ta...dconant — 06:40 PM
54C Cabinet Refinish
Roy; Personally I would have left the asbestos alone if it were my set, but you can find a modern substitute that som...Arran — 04:51 PM
Philco 71 Code 125
Looks like that might be the B- buss, so that would be correct.RodB — 01:32 PM
Philco 71 Code 125
I noticed on the code 121 schematic the center tap for the 6 volt winding and hv winding are tied together. Is this corr...dconant — 12:16 PM
Philco 45-6365 Universal IFT Instruction Manual
The Philco Parts Catalog for 1942 shows it as usable for 175 kHz, 260 kHz, and 465 kHz. The instructions will show how t...DaleHCook — 11:19 AM
Stromberg Carlson 1500 Squeal
Hello Rob, I agree with you—I have one here at my house that I need to check out. It’s way over-engineered just to make...radiorich — 11:05 AM

[-]
Who's Online
There are currently 2269 online users. [Complete List]
» 2 Member(s) | 2267 Guest(s)
AvatarAvatar

>