PCB Repair Logs Pheonix
Pheonix
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| Manufacturer | Centuri |
|---|---|
| Year | 1980 |
| PCB Image | Reserved |
| Pin Out | Phoenix |
Repairer: DarrenF
Forum Thread: Pheonix PCB Repair
Here in the US, Phoenix was mostly distributed by a company called "Centuri". Not sure about the rest of the world. Taito maybe?
Symptoms: appears to come up, but video is intermittently messed up.
Closer look: carefully observing the screen, it was fairly apparent that was a horizontal sync issue. The screen wasn't rolling vertically (all monitor references are with respect to "normal" monitor orientation, irregardless of the fact that Phoenix is a "vertical monitor" game). But the horizontal location of raster lines was intermittently haywire, creating a badly garbled image (except for the brief periods it was more-or-less OK).
Diagnosis & Repair: Pulled up the schematics and starting following the sync from the output backwards. On the 'scope the sync signal looks obviously wonky... not the regular hsync and vsync pulses normally seen. Traced it thru the inverter <29>, and the XOR <22> gate that combines H & V syncs, to the LS138 @ <8>. When I piggybacked that IC, it improved, and the formerly lame signal on pin 11 looked a little stronger. So I replaced it. Well, it was now like 30% better, but still that same issue. :/ So I kept swimming upstream. I found that one of the inputs to that LS138 looked bad (not a good TTL high/low). It was the input on pin 2, the "H6" signal. I tried piggybacking the other ICs connected to that node (<16> & <15>), but no change. So I followed the H6 line to its origin on the bottom board: the LS163 @ <4>. Piggybacked it... video was perfect. Replaced bad IC... done.
Phoenix holds a special place in my heart... it was the first game I wrote an emulator for back in 1999/2000. So I think this one will be a keeper.
