[Coco] WTB Orchestra 90 cartridge

Zippster zippster278 at gmail.com
Mon Aug 1 00:50:58 EDT 2016

Hi Jim,

Responses in-line…

PCBs should arrive tomorrow, so hopefully we’ll find out how they work later this week.

- Ed

> On Jul 31, 2016, at 11:06 PM, RETRO Innovations <go4retro at go4retro.com> wrote:
> A couple questions:
> * Looking at the schematic of the orch 90, it looks like 3 of the caps
>   are non polarized electrolytic.  

I don’t want to open mine either, but I believe you are correct.

> On your redesign, it looks like
>   you swapped out for ceramic or something similar.

Yes, I used just plain ceramics, which I suspect will be just fine here, but hey
that’s what prototypes are for.  :)

> Was there some
>   reason why Tandy used the non polarized (I had not heard of them
>   before perusing the schematic)

I can’t think of one.

> * The r2r ladder.  I assume the original resistor networks were 1/8W
>   or 1/4W Did you go with 1/4W or 1/8W on the surface mount
>   replacements?  Or, did you go with something smaller?

Bourns isolated resistor arrays.  Rated  .16 W per resistor, so somewhere in-between. 

> I hate to open my sealed cart up, or I could probably answer part of the second question.  Anyone have hires pics of an open cart?

There’s a pic in the folder here, but not very high resolution.
<https://drive.google.com/open?id=0B1sgl615FlGnLWk1akpheXhCcWs <https://drive.google.com/open?id=0B1sgl615FlGnLWk1akpheXhCcWs>>

> Jim

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