Help Identifying a Ceramic Capacitor, Please

[Grid]

I refer to the black ceramic cap center photo. I'm assuming it's 150 pf / mmf. This is in a Stromberg Carlson ASR-444 "Stereo 60." I have a parts list that does not correspond to the S-C schematic. If anyone would sell me a complete S-C service manual for this amp, I'd greatly appreciate that.

 

[kve777]

 

[kve777]

http://audiophool.com/MadeInRoch.html is a great resource for these.

 

[gadget73]

The black one I assume you mean? That one I'd take to be 150 pf. Possible its one of those running production changes, a lot of old gear is guilty of that kind of thing so the schematics may not 100% match the unit in front of you. If it doesn't have a schematic pasted to the bottom cover, about all you can do is trace it out and mark up a schematic so it fully matches your unit. I've had to do it a few times on my own gear.

 

[Grid]

http://audiophool.com/MadeInRoch.html is a great resource for these.

Oh, yes. Thank you.

 

[Grid]

View attachment 1166045

Thank you. Must be those 100 mmf ones.

 

[Grid]

The black one I assume you mean? That one I'd take to be 150 pf. Possible its one of those running production changes, a lot of old gear is guilty of that kind of thing so the schematics may not 100% match the unit in front of you. If it doesn't have a schematic pasted to the bottom cover, about all you can do is trace it out and mark up a schematic so it fully matches your unit. I've had to do it a few times on my own gear.

OK, thank you. Yep, the black. 150 pf it is then. Must be production change. Must be the ones the Sams shows as 100 mmf.

EDIT: Here's the schematic that's on the bottom cover. I'm not schematic savvy enough to locate that 150 pf / mmf. I've also attached a parts list. Notice how the part numbers do not correspond with those in the schematic. They also don't correspond to the SAMS. I have no idea from what schematics that parts list is. I have a WTB for an original service manual, where hopefully the parts list matches up with the schematic.

 

[gadget73]

the Sams component numbers may not match the S-C ones, so you probably can't use the Sams list without the Sams schematic to reference.

 

[toxcrusadr]

You can usually find it by figuring out what it's connected to. What's that switch to the left in the pics? Does one end go to that? Where does the other end go? Which pot is that in the pic?

 

[Grid]

OK, thank you. Yep, the black. 150 pf it is then. Must be production change. Must be the ones the Sams shows as 100 mmf.

EDIT: Here's the schematic that's on the bottom cover. I'm not schematic savvy enough to locate that 150 pf / mmf. I've also attached a parts list. Notice how the part numbers do not correspond with those in the schematic. They also don't correspond to the SAMS. I have no idea from what schematics that parts list is. I have a WTB for an original service manual, where hopefully the parts list matches up with the schematic.

Ah, OK, thanks, I just noticed "Folder 14." So I guess this parts list is for the SAMS full schematic, not the "alternate" as is found online. Thanks for pointing that out.

 

[Grid]

You can usually find it by figuring out what it's connected to. What's that switch to the left in the pics? Does one end go to that? Where does the other end go? Which pot is that in the pic?

That's the B channel volume pot. There are two of these black 150 mmf / pf ceramics. Yes, both go to the selector rotary switch; the other ends connect on the terminal

Ah, OK, thanks, I just noticed "Folder 14." So I guess this parts list is for the SAMS full schematic, not the "alternate" as is found online.

to a wire that goes to the ground of the 6U8. As far as I can determine, with Tom Bavis' help, one of those is for the crossover feature. It is 100 mmf in the schematic. There are two more for the loudness contour.

 

[cademan]

Is there a problem? Those ceramic capacitors last forever and rarely ever need replacing.

 

[Grid]

Hi, ye

Is there a problem? Those ceramic capacitors last forever and rarely ever need replacing.

Hi, yeah, I'm just doing my first ever total rebuild, just for--I don't know, the experience of it, I guess. Tell ya what... I don't think I'd do it again.

 

[gadget73]

With that amp, I'd be looking more at resistors than ceramic caps. More than half of the ones in my ASR-433 were way off value. I quit testing and just replaced all of them.

 

[s-petersen]

The parts list is for an ASR-333 The output tubes are EL-84 / 6BQ5

 

[gadget73]

The 444 is 7027 / 6L6GC I believe, but the front end should be very similar to the 333 or 433. The 333 and the 433 are basically the same, the 433 has a phono preamp and the 333 does not. Once you hit the output of the 6U8 its gonna be different, though still with the same basic topology.

 

[Grid]

The parts list is for an ASR-333 The output tubes are EL-84 / 6BQ5

Well, actually, there is a footnote indicating the ASR-444 uses the 7027 tubes. I have a WTB for an original ASR-444 manual but no hits.

 

[s-petersen]

Interesting, I didn't think they were otherwise the same.

 

[Grid]

With that amp, I'd be looking more at resistors than ceramic caps. More than half of the ones in my ASR-433 were way off value. I quit testing and just replaced all of them.

Yes, I know. I just wanted to experience doing a total rebuild. I'm down to the A channel bass control and I'm done. Yes, I found resistors that had doubled in value.