Why would anybody replace a device containing 4
simple components
(transformer, fuse, and 2 diodes) with something containg many more
components (the PC PSU)???
Maybe because it is very pratical, until I repair the original PSU? :)
Firstly, since the output of the TRS-80 Model 1 brick is not regulated
(or even smoothed DC) you can't just connect a PC power supply to the DIN
socket on the keyboard unit. You would have to bypass the regulator
circuitry on the CPU board (which I do not recomend doing). Also, IIRC
these 3-rail DRAMs are sensitive to the order that the supplies are
applied (IIRC the -5V supply must be present before the +12V one). A PC
power supply might be OK, it might not
Secondly, let's think about that power brick. The transfomer rarely
fails, normally the (soldered in) fuse goes first if there's a short on
the secodnary side (note that a shorted smoothing capacitor or rectifier
on the CPU board will blow this fuse). So the only things you're likely
to have to replace i nthe brick are the fuse and the diodes. Are those
really that hard to find? My junk box is full of 'em...
-tony
