On 10/06/2014 01:28 PM, Julian Perry wrote: > > In an unrelated query - I've been reviving a 1982 KU-14194HB > silver-label machine. It's now working fine (RF modulator was dead) but I'd love a schematic > for the thing, and I've been unable to locate one. Has anyone seen > one? If it's really a KU-14194HB board (the 2114 color RAM on U6 is located between CPU and Char-ROM), you need to check C107 and C108. Theses are 2 small electrolytic capacitors located left and right from the 74LS629 (which is right next to VIC) If those are black, very small and sitting directly on the board, you need to replace them immediatly (10µF/25V will do). They don't contain much, but they will leak and it's enough for C107 to destroy the trace between Pin 15 if the 74LS629 and R26. Once that connection is gone, the VCO inside the 74LS629 will no longer do its job and no clock signal will be generated. You can't go by looks, the leak might be limited to directly below the capacitor. I had to fix this trace on more than one KU board. Gerrit Message was sent through the cbm-hackers mailing listReceived on 2014-10-06 16:00:03
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