Tascam 38 Fuses

[explodingPSYCH]

I managed to blow F503 and F504 trying to address channel 4 not playing audio in repro. I'm sure something just got shorted and now I need to trace that down.

I'm looking through the service manual, but I don't see info on what each fuse is protecting.

Can someone point me to a resource/reference of what each fuse is connecting to?

 

[explodingPSYCH]

Cleaned Motherboard with alcohol, pulled all channel cards, F503 and F504 still blow immediately on start up. These are suppose to be fast blow fuses right?

I used compressed air and a vacuum on the 38's insides, I have to assume something got into the PSU, so I'll look into that next.

Would be really helpful to have a reference to where all the fuses on the fuse board are directed!

 

[explodingPSYCH]

My issue is similar to this post: https://www.tascamforums.com/threads/tascam-38-issue-blowing-fuses-503-504.8466/

The difference being that I have different diodes that are reading as faulty than the OP of the other post. My bad diodes are D814 and D815 where his are D812 and D813

Would love any advice on how to proceed and of course if anyone has general info on where the various fuses go (it looks like F503 and F504 lead to the PSU near the previously mentioned cluster of four diodes.

 

[explodingPSYCH]

Much like the post linked above, I was able to solve my initial issue (no audio input) by replacing the bad diodes. However, now my take up motor isn't rolling. Time to hunt further!

 

[SkywaveTDR]

I am not understanding why so many guys are blowing fuses. I have had very few if any decks that blow fuses or need new diodes. The fuses are source power for the plus and minus 15 Vdc supply to the Mother board. It is the motherboard where people most the time make the mistakes that cause fuses to go out. It is usually not the cards but pins soldered together that short the plus and minus 15Vdc supplies together. If take up is not running check position of Edit switch as it shuts off the reel motor.

 

[explodingPSYCH]

Yup. Edit switch was activated! I always forget that exists until this happens.