31 Jan
2011
31 Jan
'11
1:24 p.m.
Is this a normal sized board in one of the card
guides? As Jules said,
the RGB output board isn't, it's a little board an an L-brackt fixed ot
the rear panel.
It's the left-most card next to the floppies. It has a colour modulator on
it which goes direct to tv-out on the back panel, also composite which goes
to the monitor connector. I assume you also havea modulator on the text
video board (VDU #1). The
TV output socket cable is connected to that if you don't have the PAL board.
Nope. No modulator on VDU #1.
I really would
try the series light bulb trick in this case. Start with
all the secoadary wires disconnected from teh trransfoerm, and power up
wit ha ligth bulb in series with the mains live wire. It should be dark.
It was. Fan action too. If it glos, there's a short somwhwere.
Power-down, reconnect the secondary
wiring, but have the PSU unplugged from the rest of the machine. Power up
a gain with the bulb in series. It will probabyl flash at power-on as the
smoothing capacitors charge, and it may stay glowing, but dimly. If it's
bright, I think you have a shorted rectifier or smoothing capacitor or
similar.
It didn't. The power light stayed on and the fan kept spinning - it's a 240v
fan.
This encouraged me to refit CPU, VDU#1 and the 80 column board. Both CPU and
80col need power and the 80col is permanently wired to VDU#1. However, while
the power light stay on and the fan keeps running I get no display on my
Hitachi 9" monitor (the one you remember from school). I know the monitor
works because it came with my homebrew NASCOMII which is fine. What I don't have (gah) is a multimeter to check
the voltages on the floppy
connectors....I left it at work. More tomorrow!
You only have one multimenter? What about a 'scope?
-tony