30 Nov
2004
30 Nov
'04
6:43 p.m.
Jim Brain wrote:
Get a 2x23 edge connector, a bit of circuit board etched and shaped to
match the edge connector on the ZX81, and a bit of ribbon cable. Wire
them together.
Gordon.
Glen Goodwin wrote:
From memory, desolder the resistor inside the UHF modulator that goes
to the middle pin of the phono. Poke one lead of a 75 ohm (or
thereabouts, 68 is common and close enough) through the polythene
through the polythene bush, and solder it to the socket instead. Solder
the emitter of a small NPN tranny to the other end. Solder the base of
the tranny to the video lead, the other one that goes through the bush,
and solder the collector to the +5 supply where it goes into the
feedthrough cap. Finally solder another 75 ohm resistor between the
junction of the first one and the emitter, and ground. You may need to
adjust those values, I may be wrong.
One transistor + one resistor + one monitor =
rock solid display.
Any links? A dormant unit sits on the shelf. Scraps from
the junk box and 30 minutes time will yield a cable which
provides enough distance from the ZX81 to eliminate the "wobble"
problem.
Again, links?