fostex r8 keeps stopping

tapeboy

New member
Hello! My Fostex R8 keeps stopping on me. If I swop the 'rollers' I think they're called - you know the big wheels left and right - it runs fine, except (!) that I lose the use of the locate function. Hence, the read out just says 00000 and I don't know where I am.
The left wheel has black and silver foil inside it and I was told if this is scratched it could be the problem. But after talking to a Fostex expert, I was told it would have to be horrendously scratched (and it isn't) to stop functioning. He said I should look at the sensor unit behind the left wheel. I looked and it 'looks' okay but I don't dare touch until I know more. Can anybody help please!!!!!??
 

skywaveTDR

Active member
Every one likes the magic wand kind of repair. This rarely works. Do what a Technician does and put a scope on the opto output. If the correct voltage is there the problem is not that. In another brand I have found opt sense circuit in rare cases go down in voltage that then caused them to not be recognized by the TTL level definitions. I could change the sensor but they are backwards constructed from what you can get now? So I fixed the problem with a thing we call a pull up resistor that shifts the level a small amount upward to allow the TTL definitions to be satisfied. I am sure Fostex is having the same problem with opto item as everyone else.
 
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