Tascam 85-16b timer/clock

[hateriarch]

This is a post I put on the other tascam forum.

--snip--

I have a problem with a tascam 85-16b. There is a small circuit board with 2 little sensors on it that read the slotted tab at the bottom of one of the spindles for the tape. As this slotted tab spins it advances the counter. Forward or back or whatever.

The counter on my deck is moving between 99:59 and 00:00

One of the traces is broken and I have soldered a small piece of wire to the other point of the trace to make the connection. This however doesn't appear to be fixing the issue.

I was hoping someone here could help me understand what I need to do to get this fixed, or maybe even point me to a part supplier/used machine I could buy a replacement from.

I cannot tell if the sensor itself is broken or just the board is bad?

I have tried locating this in the schematics and am not finding this specific board or part. I am not sure what amount of voltage should be there or what.

Any help would be greatly appreciated.

--snip--

I have images of the little sensor board I can post/send. I have made sure all the connections are good, I get 15v across the connectors for the sensors. One of the connections the voltage moves around a little as I spin the roller and the slotted tab moves between the sensors.

If there is a way to get the schem for this part that would be great. I don't see it referenced anywhere in the manual.

Thanks

-greg

 

[hateriarch]

here is an image of the slotted tab on the roller I am talking about

 

[SkywaveTDR]

Hi Greg,
The first thing to do is put a scope on the opto outputs to see if they are still switching from 5V to near 0. These opto interrupters can still be replaced if needed. A broken trace come from some reason so what else happened to the machine that we are not knowing about?
I have two of those machines in the shop and do still work on them on occasion in the Chicago area.