...and to fix a dying power socket, TwinHead replaced the mainboard. They explained that they had no spare power sockets, but did have spare mainboards...
It also had the RAM replaced. Not sure why, maybe the new mainboard featured a different RAM standard.
Either way, it runs well again, hoorah!
Now unlike the 15” CRT I was using, I’ll be able to read what I’m typing. It may not help, but I’ll be able to see what I’m doing wrong now. (-:
Speaking of CRTs, have you tried to buy a new one recently? It’s getting very difficult. Since a 19” flatscreen is about AUD$280 (+GST) and a 17” is a mere AUD$215 (“with speakers”), the idea of shelling out $3 or $400 for a limited-lifespan CRT does seem a little absurd. OTOH, they do typically (as I’ve said elsewhere) come with high resolution & greater colour depth.