Has anyone experienced a "no trigger" condition in a 2430. Scope fails
on diag test 9300 /trigs/repet.
Yes. I have one :-(
Functionally, the trigger on mine is intermittent, sometimes it seems
to work a bit, other times no trigger whatever A or B.
Mine fails 9121 9122 9123 9221 9222 and 9300.
(i.e. A passes, B fails, Rep fails.)
It also sometimes takes hours to run the power-on test at all,
it seems to get stuck in the trigger test (test part 9).
As Andreas says, the service manual gives details on looping
failing tests and scoping what's going on. In my case one can
see the (passing) A test doing its "binary search" converging
to the correct trigger level, for both directions.
When running B however the result of every step goes the same
way, no convergence. The inputs to U370 look right to me, the
output on pin 63 wrong.
Interestingly, I found a solder whisker short under the U370
socket (pins 14-15) but removing it didn't help. :-(
Pin 14 is not shown on the schematic, so I assume it's unused.
I suspect U370, but haven't laid my hands on a replcement to
try. (Is there anyone out there near Southampton with a working
2430, willing to do a test swap of U370 and/or U150?
Take care to get adequate cooling if running with the case
off. There are stories of people cooking the hybrid modules
on the main board.
Regards,
Mike.
