[R-390] R8B tuning mechanical encoder

[2002tii]

Todd wrote:

> I sent an R8 in for repair to Drake and they were very reasonable.
> They currently list repair for the R8B at $25 per quarter hour or $100
> per hour - they could replace an encoder in well under 1 hour. I have
> heard trying to replace the encoder yourself is tricky and you could
> end up with more problems if not done right.

As I wrote previously, I modified the encoder in one of mine. It was
not hard to remove with only minor disassembly (this from the
perspective of someone who used to fix electronic gear for a living).
As I recall, it took a bit of jockying to get the encoder card out
without more extensive disassembly, but nothing the careful boatanchor
mechanic should be concerned about. (The card is small -- maybe 1" x 2"
-- and mounts to the chassis by the encoder shaft collar, like a
potentiometer or switch.) The encoder mounts to the card like a
PC-mount potentiometer, so unsoldering and replacing it should be
trivial. There is nothing particularly fragile about them, so I don't
see any reason not to recommend doing it oneself if one feels
comfortable replacing a PC-mount pot. I don't think it took me longer
than 20-30 minutes from start to finish, and I pulled the decoder
itself apart and put it back together. (Again, don't try this unless
you're willing to replace it -- they are not intended to be
disassembled.)

I did not know that the previous models had optical encoders. I may try
to see if the R8B can be retrofitted, not because I've had problems
with the mechanical encoder, but just on general principles. Does
anyone have a service manual for the R8 or R8A (any R8 with an optical
encoder) they can copy for me? (I would be happy to trade a copy of the
R8B manual.)

Drake's parts and support people are among the very best I've ever
dealt with.

Best regards,

Don