30 Nov
2006
30 Nov
'06
7:53 p.m.
Gordon JC Pearce wrote:
I still have my (almost) fully-loaded Atom
I was hoping that by 'fully loaded' you meant that it had the BBC BASIC,
Econet and Colour boards :-) (I've never seen a real example of the latter,
although I know that there's at least one in the UK)
at my Dad's work over 20 years ago. The bottom of
the case is rather
scorched where the PSU heatsink has been struggling with all those
2114s! I'm guessing that's why they wanted rid of it - it ran for about
5 minutes then would shut down because the regulators were overheating.
I remember him being rather concerned about how hot his bench PSU was
getting when running it, and eventually it clicked that if it was
pulling down 3.5A from the thing then there was no way two 7805s would
ever handle the strain.
You know, I have a feeling that you can get 7805 regulators that'll handle 2A
each - but maybe they weren't around when the Atom was new. Even then, just
doubling them up and hoping they'd share the load evenly was always going to
be a bit risky.
Then, of course, the unheeded technical manual turned
up. I had a quick
look, and right in the first few pages it mentions removing the
regulators and bypassing them and then putting a *BIG* label on the back
saying that it's for 5v now, not 9v...
There's a lot of Atoms out there that have had the regulators bypassed, no
sticker added, and then subsequently had 9V shoved through them :(
cheers
Jules