Mesa 7c80 output repair possible?

Hello everyone,

unfortunately I damaged an output on my mesa 7c80 card by wrongly connecting a relay. The output does not open anymore but the led turns on.
Can anybody tell me which parts usually get damaged and need replacement?

Thanks a lot -
Jan

Probably shorted the output transistor (6 lead SOT-23-6)

Like many components, these are hard to find now but here is a list of
suitable replacement parts:

PMN55ENEH
PMN55ENEX
AO6420
BSL606SN
DMN6040SVT-7
FDC5661N-F085
SSM6K809R,LF
FDC5612
SIL05N06-TP
SQ3426EV-T1_BE3
SSM6K819R,LXHF


 

Hi PCW,

thank you very much for your quick reply!
As you already mentioned it will be hard getting hands on these components.

I will keep you updated if I find one and replaced the part.

Best regards
Jan

Repair is definitely possible. If you haven't already fixed it, consider contacting Mesa first as they may have the parts in stock. For any other repair shop, ask "Can you source and replace a single TSOP-6 MOSFET?" A salesperson may not know what that means, but a tech will. If they don't know, look elsewhere.

If using outputs to switch something inductive (like a motor or relay coil), it *must* have an anti-parallel diode across it. This is to prevent the collapsing magnetic field at turn-off from creating a high voltage which will destroy these devices.

Note, adding said diode will slow down the "release" of a (mechanical) relay substantially.  If whatever the output is used for is timing-sensitive, consider a SSR solid-state relay or opto-coupler, etc.