TRS-80 Fireworks

Rob Jarratt robert.jarratt at
Wed Aug 28 03:32:48 CDT 2019

I have had this problem in various PSUs, particularly in MicroVAXen. In my case replacing them has been fairly straightforward. Not had this with my TRS-80 (Model 1) though. I think it is a fairly common problem.



> -----Original Message-----
> From: cctalk <cctalk-bounces at> On Behalf Of Marvin Johnston
> via cctalk
> Sent: 28 August 2019 09:16
> To: ClassicCmp <cctalk at>
> Subject: TRS-80 Fireworks
> 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.

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