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Stromberg Carlson RP-766 C Restore

A

anjeesmith

New Member
Hey guys! Brand new to the forum. Just inherited a Stromberg Carlson RP-766 C from my grandparents. They bought it new sometime between '62-'65 I believe. Kept in unreal condition. I can't find much info on the 766, but I see bits and pieces about the 763. From what I can tell, I THINK I'm looking at the ASR 120 amp in my 766 based on the fact that there are two power tubes per channel. I've taken the original TT out and dropped in a new-ish Pro-Ject Essential II, which I've connected to the SC phono inputs. My goal is to get this thing in tip top shape, primarily to be used for vinyl listening.

I've got a little issue that's keeping this thing from being a dream. I get FM/AM stations fine, but when I switch to the phono setting I get nothing. Is this a preamp issue?

Where is the preamp in the 766? In the ASR120 or the SR130 tuner? Based on the schematic of the SR130, I don't see anything that looks like a preamp after the phono inputs. I'm not 100% it's the SR130 in my 766 lol.

Will ABSOLUTELY be replacing caps before anymore testing haha.

Apologies if this info exists in another thread. Any help offered would be greatly appreciated!
 
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According to @Tom Bavis 's very informative S-C Website (scroll down page for schematics etc.) it refers you to the ASR-120, with schematic & Sams available for download. The Sams gives the SR-130 schematic for preamp/tuner
 
I did find this site earlier this week. This schematic is what I was referencing in my observation about not seeing a preamp-type section after the phono inputs. I'm not a very experienced schematic reader, so if anyone could help me identify an area of the circuit to check first to get the phono section working, that'd be great!
 
if I'm reading this right, it doesn't have a phono preamp. The original was most likely a ceramic or crystal cartridge. If its got a flip-over needle, you can bet your lunch on that. Those had an output that was basically line-level. If you put a phono preamp between your ProJect and the phono input on the S-C, it should work as expected.
 
Ah gotcha. I didn't realize cartridges of that kind could output line level signal! Makes sense why no preamp though.

Regarding cap replacement, I know there are a few existing threads that go in to that... finding ones that are equivalent to the ones in the big can on the ASR120 etc.. I'll check those out.

Thanks!
 
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