AudioRoundTable.com - RDF feed
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description: Audio advice and discussions with audiophiles and professionals. Free discussion forums, open to all and frequented by industry experts. Ask questions and get advice on stereos, speakers, hi-end amplifiers, pre-amps, home theater, tube hi-fi, turntables, vinyl, tweaks, music, films, video, DVDs and more.
items: Need schematic -- RCA
items: Re: Need schematic -- RCA

Need schematic -- RCA
type: item
description: 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
creator: Mark Williams
date: 2004-12-04T02:39:11-00:00

Re: Need schematic -- RCA
type: item
description: 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.
creator: Wayne Parham
date: 2004-12-04T19:55:13-00:00