> Tonight I replaced the leaking capacitors on the +12V/-12V board, and also > replaced the two similar ones that looked and measured fine. I put the PSU > back together, put in a couple of less important boards and drives, and the > machine now seems to power on OK. I measured the ripple using the power > connector for the front panel and that looks OK too. Unfortunately though, > that connector only sends out +12V, +5V and -12V. It does not have output > for +3.3V, so I have not, so far, been able to check the ripple for this. It is a bit > awkward to test on the bench with a dummy load. > > As I did not replace the capacitors on the +5V/3.3V board, because the > underside is very hard to access, and I am reluctant to pull them off and > solder from above, I would like to be sure there is no ripple on the 3.3V > supply. So, I was wondering if anyone has any neat tricks for probing the > +3.3V supply with the PSU installed in the machine? > > Next job is to replace the capacitors on the little DSSI terminator, they are > easy to change. >
I spoke too soon :-( The machine stayed on for a couple of minutes and then powered off. I suspect there is a problem with it detecting an overload that may not actually be there. Looks like I will need to get a dummy load and put it on the bench to see if it still happens there. I do recall that when it first failed it would stay on for shorter and shorter periods each time I tried it. So perhaps there is some component warming up and then causing a failure? Regards Rob
