Need help troubleshooting Logitek Surround Ultra-Vu

[elskardio]

Hello,

I have a box of 6 Logitek Ultra-vu and it runs on 9V DC. I was building a new power supply for it and by mistake sent 13.5V to the unit. The Leds turned on for 1-2 seconds and then went black. Now the unit won't turn on at all. I've looked at every components on the meters board and nothing seems burned or damaged.

I tried to power the unit with my bench PSU and it goes in overload protection...

Any help on how to troubleshoot this would be greatly appreciated!

Here's the schematic of the input card. The box consist of 3 in series.

http://tinypic.com/r/6yialz/8

Could it be the MAX1232 IC?
Thank you

 

[moamps]

If you are lucky you have  only one or both regs (78l05 and 7805) faulty.
Check also zeners 1N4734.

 

[elskardio]

I just realized that both regulators are not installed on the boards... pin 1 and 3 are jumpered.
I'll test the zener diode to start

 

[elskardio]

Here's a picture of the board

http://tinypic.com/r/258mght/8

 

[elskardio]

Ok I just checked the zener diodes and they're good...

 

[moamps]

Try to power it with 5V using your bench PSU. If there is still a short somewhere, remove the PSU and try to find it using a DVM (set to check the continuity to ground)  by pulling out ICs from their sockets. There is also a tinny possibility that some of the tantalum caps are faulty.