Showing posts with label Rant. Show all posts
Showing posts with label Rant. Show all posts

05 December 2012

Emulator II Repair part 2

Two days of on/off poking around with a multimeter and pulling each and every socketed IC, de-soldering any capacitor across -15v and AGND and removing a whole group of capacitors that had at some point been (badly) re-soldered yielded absolutely nothing.

The interesting thing is that the earlier repair work had been the filter capacitors on channel 2 and it wasn't the only work on that channel. One of the ICs had been replaced at some point, but typically it was one of the few that were not socketed, which is itself odd as I had thought all E II's had every IC socketed. The replacement IC had been socketed, but it looks as though whoever did the work lifted a pad on the top side of the board and attempted to get the pin in contact with the remains of the track by applying a huge amnount of solder - which ended up shorting two pins - between -15v and AGND.
Previous "repairs" circled

Removing and replacing the socket resulted in me lifting another pad, but I fixed this and the first one with a pair of wires under the board. The short is gone and everything that should be connected is. I'm want to test it, but as I managed to destroy some of the capacitors that I removed trying to trace the problem, I am now waiting for parts. Some of the other ceramic capacitors are visibly cracked and although they have not gone short yet, they likely will in time, so I intend to replace every bypass capacitor on both PCBs - about 150 of them. Oh and that nasty replacement jack just has to go.

Part 3 to follow once I have the parts...

15 April 2012

Shruthi-1 coming

I have ordered a Shruthi-1 - more precisely the limited edition Shruthi-1 4 Pole Mission. Hopefully I'll get a chance to build it next weekend.

In other news. I now have all the parts for the Gristleizer and Echo Base - except the PCBs. <rant> Deliveries from the US to UK seem to be getting slower - and more expensive what with the post office's "admin fee" for paying import duty that is often several times the cost of the duty itself........ </rant>