I've got this lovely old Obelisk 150 Power Amp made in 1992. The power amp is working nicely. But the input selection using logic IC's does not work.
The +15V line is down to 0.8V because something is drawing too much current.
Hence there is also no +8V line. I have already removed 3 faulty 4051's. Still no joy.
The analog stuff is fairly easy to work out. But the digital switching is a pain without circuit diagram. I wonder if there is anyone out there with schematics.
Attached is a photo of the board manufactured 3/5/92 P2008 ISS.2
Hope this helps to narrow things down.
Many Thanks
The +15V line is down to 0.8V because something is drawing too much current.
Hence there is also no +8V line. I have already removed 3 faulty 4051's. Still no joy.
The analog stuff is fairly easy to work out. But the digital switching is a pain without circuit diagram. I wonder if there is anyone out there with schematics.
Attached is a photo of the board manufactured 3/5/92 P2008 ISS.2
Hope this helps to narrow things down.
Many Thanks
Attachments
Thats work in progress. Needed space to get my ic liftrr under the 4051's.
The elco's look good. Still they need checking. There. Are too many.
I think my next step will be to rig up a 10 amp constant voltage power supply and look for smoke signals 🔥
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