[sjt99]

Hello everyone, i have two rs232 broken.. one is ti and one is Corcomp. All two present equal problem.. when i insert in PE Box the Ti99 light on but go in crash.. no video present.. only light blue color on screen.. I for test i check many component on board and discovered that if i leave IC 74ls125 the TI99 start at working.. (obvious the cards no work). If i understood well seem that the signal extint stop the autostart dsr card on PEbox and crashed all.. any idea for solve this problem??

That's strange that they both fail when their DSR's are accessed.
Do you have any other cards...that work?

Try and find a local fellow Ti'er and test the cards in another pe box.

If you verify these cards are at fault, the first thing I would suggest is to replace the firmware. Remove the old firmware install socket(s) and install new eproms.