Germanium Olympic (Helios) Amp Cards

[Voyager10]

Just out of interest, I drew up this overlay from @kags photos:

The schematic then looks like this:

It's not clear from the photos what the values of C5 and the added decoupling cap (CX) are, or the transistor types. This basically matches what @Whoops posted, except that this one has an R4 (47K), and some of the caps are larger.

 

[Whoops]

Just out of interest, I drew up this overlay from @kags photos

Hi mate, very cool, that’s very useful.
Thanks for sharing

Could you please let me know where are “Kags” photos?
I think I’ve missed them

Thanks

 

[Voyager10]

Earlier in this thread, Dec 8 2023: Germanium Olympic (Helios) Amp Cards

Looks like there were quite a few variants built on the same PCB, judging by the follow-up post.

 

[Whoops]

It's not clear from the photos what the values of C5 and the added decoupling cap (CX)

This might or might not be the same values as fitted in Kags modules,
but I checked all the schematics I have (they're in the technical documents section also), and the schematics that show those parts the values are these ones:

C5 125uf or 250uf/15V

Cx 47uf or 50uf

This basically matches what @Whoops posted, except that this one has an R4 (47K), and some of the caps are larger.

All the schematics in my archive have R4 (47K) fitted, the exception is the "Hyde Street Studios" schematic. I thing that it might be an error in the schematic itself, we have to consider that it's not an official Helios schematic, it's drawn by hand and we don't know by who, so there might be some errors in that one.

 

[InterstellarObscure]

For comparison, here's another MMC-1 photo set (2 MMC1 beside a 15C1). You can probably see the 125uf for C5, 47uf for Cx, as Whoops noted. As on the 15C1, the MMC1's have TI 2N4058 and 2x TI 2N3707. These cards are from a cache of Helios console parts that I've been working towards rebuilding into modules: