Tascam 38 No sound in Sync Mode!

All fuses are working. Everything else is soldered fine.

Is there a way to check if the IC's are not broken? I put 2 SN7400N's in place of the exploded ones. Is there maybe a difference in the old IC's and the new ones? Or can I just use SN7400N as a part replacement?

Thanks

If the SN7400N's are what is called for then you should be OK there. If not you have a problem. Make sure you have the Xref correct.

Give me the Tascam IC# and I will check a Xref table.

I would also go through and check every transistor on the control board. I would start with the large rail mounted unit, and then move on from there to everyone.

You are probably not getting a signal to the IC's due to gating through some switching transistors.

I've already checked all the transistors. They seem fine, they all measure around 700. I'll check them again.

Tascam IC: M74LS00P (614002)
and the one SN7474N: M74LS74AP (5170E2)

The new I swichted with the exploded ones:
SN7400N (09E76VK)

Thanks again!

I do not know what the "700" measurement is you ststed. That makes no sense to me. Either there is conductivity across the pins or there is not.

I think you need to check all the transistors again.

I'll look at the Xref for those IC's

Tascam IC: M74LS00P (614002) - I do not see this one in there. I see a SN7400N
Where did you get the "P" designation?

I have a digital multimeter that can measure diodes. I've checked every transistor and they all measure around 567 when I measure PN and zero when I measure NP. I suppose that should be right and the transistors should be working?

Concerning the my SN7400N IC, I've found one on ebay:
http://www.benl.ebay.be/itm/M74LS00P-Ma ... 56513a84f4

What do you mean with the "P" designation?

This is the one you stated- Tascam IC: M74LS00P (614002)

Where did the "P" designation come from?

I don't now where the designation comes from, the original Tascam IC code is stated like that. I've just read it from the IC itself.

I've just found a control PCB on ebay:
http://www.ebay.co.uk/itm/Tascam-34B-Re ... 0948852173

It's from a Tascam 34B, but it looks exactly the same. Do you think it could be switchable with mine?

Definitely No! They may be similar but not the same.

Don't waste your $.

You need a 38 series control board from a unit that is well below unit S/N 4000000 series.