Home » Audio » Radio » Need schematic -- RCA
Need schematic -- RCA [message #25606] Fri, 03 December 2004 20:39 Go to next message
Mark Williams is currently offline  Mark Williams
Messages: 48
Registered: May 2009
Baron
Hi,

Would anyone have a schematic for an RCA Victor model 3-X-521? It's a small table radio supposedly from 1951. Serial no. is U 124327.

It works, but hums fairly loudly. I see one burned resistor but I cannot make out the color code. When I know the value, I'll replace this bad resitor and hope the hum stops. Is it likely to be the fix?

Would appreciate any & all help.

Mark

Re: Need schematic -- RCA [message #25609 is a reply to message #25606] Sat, 04 December 2004 13:55 Go to previous message
Wayne Parham is currently offline  Wayne Parham
Messages: 18670
Registered: January 2001
Illuminati (33rd Degree)
You probably need power supply capacitors. Look for capacitors inside the radio with values around 8uF to 20uF. You'll probably find two or three; Replace them with polypropylene 250v caps and the hum will probably go away.

I found a schematic that may be for your radio on Rider volume 14. It has 35Z5, 50L6, 12SA7, 12SK7 and 12SQ7 tubes. That was a very common tube set for RCA radios. I have a couple of chassis like those myself. One of mine was just like yours when I got it - Working but with a lot of hum. I replaced the power supply caps and it was much quieter.

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