Anyone change an optocoupler on an old Mac tuner?

jlovda

Things I loved from the 60's and 70's
Subscriber
Has anyone changed the optocoupler (LDR) on the multiplex board of an MR74 or MX113. Any problems to look out for?

Thnks
 
Had to dig this up.. Got this recommendation from Terry years ago.

Replace the 144-014 opto on the MPX with a VTL5C9, will need 1K in series with the emitting diode and about 180 ohm across it to adjust the sensitivity as to not mute the signal when muting is off.
 
Been a while since I actually had to replace one of these. Tried a NSL-32. With the 1K dropping resistor and working without a 180 ohm resistor across it for sensitivity. NSL032 is readily available compared to the VTL5C9.
 
Back
Top Bottom