e-licktronic Forum

There are two 2SC878 transistors in the parts list (Q82, Q83). They did not come with my kit and are not in the linked mouser bom. Searching mouser, digikey, and tayda, I can't seem to find any.

Where can I source these? Also, are they necessary? They seem to implement a muting function. If I don't put anything there will things still work?

Those are long obsolete so I bet you'll have a hard time finding them (though it's a noble pursuit to keep the unit as original as possible).

NTE85 is cited as an equivalent but that's a common error too since it entire;y depends on voltage and Q tolerances. Older documentation shows these as options as well:

- 2SC933
- 2SC367G
- 2SC 68
- 2SC321H
- 2SC1231

You need to compare datasheeets since the BCE values will vary. You're looking for one that's as close as possible to the 2SC878.

If someone can speak to the BOM and 'is it necessary' question I'd like to know too. I see 2SC945 and 2SA733 used everywhere (which was also common for Roland back then) but indeed, some transistors should be different and appear to have been 'compensated for' in these kits and BOMs.

Good luck!

The originals from the service manual are 2SA1015. Most will work here as the muting function is to keep noise off of the output during powerup and cpu boot on the original.