iainmaoileoin
Experienced Member
I have 2 x 11/84s. Do they count as vintage? if not - sorry. if so
1 runs
1 has a PSU problem on 1 of them. H7202B I think for the 5volt 60 amp PSU.
I have pulled boards etc. The broken system shows correct lights on the PSU for "OK"
but the front panel shows status "77" - power or termination etc etc.
I have swapped boards into the working one and everything seems to work.
I have checked bus grants/continuity and that SEEMS OK.
A scope on the 5volt shows 6ms at 5volt, 4ms dropping to 4 volts and the recovering.
The working system shows a steady 5volt.
I know enuf to be careful but I dont know enuf to get started.
That is about a drop every 8 ms -> so about 120Hz - I am on 50Hz mains so .....
Anybody with any skill in the area to suggest where to start?
1 runs
1 has a PSU problem on 1 of them. H7202B I think for the 5volt 60 amp PSU.
I have pulled boards etc. The broken system shows correct lights on the PSU for "OK"
but the front panel shows status "77" - power or termination etc etc.
I have swapped boards into the working one and everything seems to work.
I have checked bus grants/continuity and that SEEMS OK.
A scope on the 5volt shows 6ms at 5volt, 4ms dropping to 4 volts and the recovering.
The working system shows a steady 5volt.
I know enuf to be careful but I dont know enuf to get started.
That is about a drop every 8 ms -> so about 120Hz - I am on 50Hz mains so .....
Anybody with any skill in the area to suggest where to start?