Matt wrote: > On 28/08/2019 09:15, Marvin Johnston via cctalk wrote: > > I'm just curious how many people have powered up their TRS-80 > > computers, and ended up with a bang and a room filled with smoke? > > > > So far, I've gotten the fireworks in two out of two TRS-80s (model 3 > > and 4) when they were powered up. In both cases, the problem was with > > the main line filter capacitor mounted on one of the power supplies. > > The computers continued to work which was my first clue the problem > > was not serious :). > > > > Is this a normal problem with these older computers? I'm used to > > seeing the electrolytics give problems, but this is the first time > > I've seen one of the X type line filter caps blow. > > This is very common for these paper line filters. I've had the same > failure with an Osborne 1, DECserver 200, DELNI and PDP-11/73. There are > many more devices that have them; generally anything with an Astec brand > power supply. I replace them before even powering up these days. >
I've had several instances of it with BBC Micros, also containing Astec brand power supplies. Typically, when switched on after a long period of idleness, the machine works fine for minutes to hours, then there is a quiet pop followed by a whoosing noise and smoke starts pouring of the mains filter capacitor while the machine continues to work away quite happily. Regards Peter Coghlan.
