RCA Victor Canada SCH884 – looking for information

[Elektrishun]

Hello

I am a new member trying to gather some information about a recently acquired RCA Victor Radio and Phono Combination. The model number is SCH884 and the unit was made in Canada. Despite numerous search attempts I cannot find information on this radio. I haven’t attempted to power this unit up yet but I was told that it was working. Any information and opinions would be greatly appreciated. Thank-you!

A little background… I am a retired journeyman electrician with an interest in electronics new and old. Among my interests I like to build circuits for a variety of projects including an FM Transmitter, Capacitor meter, and a lab DC Power Supply.

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[Les Dickson]

Radiomuseum.org lists several rca units in the SHC series from shc-460 (1958) to shc765 (1963) if you go to the radiomuseum.org site and search by the exact tube lineup you may find a schematic that will help.
Good luck and welcome to the CVRS.

[Elektrishun]

Les,

Appreciate the response. I have been to that site and a few others. I now have a schematic that might be close.

Thank-you

[Elektrishun]

I have the electrical schematics for my radio. I am in the process of replacing the electrolytic capacitors. Nothing has been disconnected yet as I am waiting for parts. While I wait I have been mapping out the multi-connection capacitor. This capacitor’s specs are:

– Plessey
– 60-60-40-20uF
– 350V DC
– 425V Surge

In the schematics the capacitor is identified as “C45A @ 60uF, C45B @ 60uF, C45C @ 20uF, and C45D @ 20uF“. I am not certain of the pinout for this capacitor but obviously one of the connections is 40uF. Any thoughts as to why there is a discrepancy between the schematics and the actual capacitor? Until I am ready to measure each connection of the capacitor I know one connection will not match the schematics.

BTW – I found another schematic online that appears to be close to the one I ordered and the specs are the same for the multi-capacitor -> 60-60-20-20. I know the history of this unit. It was purchased brand new, was never repaired, all original. Multi capacitor is marked with “May 63” so another indicator that it is likely original.

With my capacitor order I missed this discrepancy somehow and ordered what I seen marked on the capacitor despite looking over the schematics, as well. I am using 4 individual capacitors to replace the original. I ordered 60uF @ 450V DC (x2), 40uF @ 450V (x1), and 20uF @ 500V DC (x1). Should I carry on and replace everything as I found it or order another 20uF capacitor and follow the schematics?

Any advice is appreciated.

Thank-you

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[westcoastjohn]

Assuming your stereo uses the 6CA4 rectifier, you can search for the data sheet by the tube name, and I use the radiomuseum.org pages to see a little schematic for the tube. In the drawing, they show a filter cap marked “50 mfd max”. If your RCA schematic shows a 60 mfd there, they were already exceeding the original specs and getting away with it, but you would not want to exceed that.

I haven’t posted here before so this is a kind of test to see if anyone reads these forums. 🙂

• This reply was modified 1 month, 2 weeks ago by westcoastjohn.
• This reply was modified 1 month, 2 weeks ago by westcoastjohn.

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[Elektrishun]

I have the electrical schematic and it shows 60uF in that location. As well, it’s part of an original multi-cap so I can only assume it was designed to function with a 60uF.

• This reply was modified 1 month, 1 week ago by Elektrishun.

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[westcoastjohn]

Thanks for the reply, shows there are still active members here..
I wasn’t criticizing what you did which was to replace what they used at the factory. There are other examples where the engineers have exceeded the max value shown on the tube data sheet, so I think that proves that it is alright to go a little higher in capacity. The first cap has to absorb the inrush of current at
cold startup, and that current flows thru the rectifier. Sometimes the engineers put a resistor in line in front of the cap to snub the current for that first millisecond.

[Elektrishun]

Criticize away… Any discussion that leads to a possible solution is good. And I think it answers my previous question about the discrepancy where the schematic shows a 20uF cap but they used a 40uF cap (part of the multi-cap). So I will stick with the 40uF replacement since that is what this radio used for years.

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