Hi, I'm new...

[Tony Duell]

> Ok, here's the full story :
> 
> 
> I have had my Amiga 600 since 2001 and have
> added a few bits over the years:
> 
>  - 2.5" 4GB harddrive (I can't remember the 
> make and model at the moment)
> 
>  - 1MB RAM (in trapdoor underneath)
> 
> 
> I also have a 4MB PCMCIA RAM card which is
> rarely used, and 2 external floppy drives
> (one doesn't work), with only 1 connected up.
> I haven't upgraded any of the kickstart or
> ROM chips, they are the same as when I bought it.
> 
> I run WB2.05 (and am happy with it) with
> kickstart 37.300
> 
> I don't know the board revision number off-hand
> but I can find out if required.
> 
> 
> My harddrive used to power down (powersave?)
> after not being used for say 20/30 mins and
> happily power-up again whenever I tried to
> access the drive (via WB or via AMOS BASIC).
> 
> However, around April/May this year the drive
> started to randomly power down and then,
> usually, almost instantly power back up again
> but WB nor AMOS could access the HD. Any
> attempt to do so would freeze WB or AMOS.

My first comment is that this set-up worked correctly for almost 5 years. 
This means the set-up is capable of working, and that the fact that it 
now doesn't work means something has failed (rather than, say, an 
incompatability, or a marginally-rated PSU, or...)

> I figured (as you would) that my harddrive

Actually, I might not. My first reaction would be to stick a voltmeter on 
the power lines. 

[...]

> I popped along to www.amiga.org and posted
> my problem up there and peeps then suggested
> it might be a flaky PSU. I got myself an
> A500 "heavy brick" model (AFAIK it's compatible

Again, since the original PSU worked for a long time, it would appear it 
was adequate. I don't like changing parts of systems that have worked 
without a good reason.

> and gives more power if required) by chance
> (I was planning to get another A600 PSU)
> from www.amigadeals.co.uk
> 
> Everything appeared to be fixed. However, my
> A600 was running hotter than normal. I have
> always put a plastic pen above the air vent
> bit at the top of the machine (by the F1-F4 keys) an
> d it used to always be cold. With this
> new PSU it was warm and the underside of the
> Amiga 600 was hotter than normal.
> 
> I posted my concerns to either Amiga.org or
> CAR and then someone suggested that it might
> be a faulty resistor. He claimed that the

I doubt it very much. If it's the resistor that's getting too hot, then 
it's dissipating too much power. In a constant voltage set-up (that would 
be the most likely), it would have to fall significantly in value for this 
to haeppen. Which is not likely. I suppose a faulty resistor could upset 
the biasing on some other component, and thus cause that to pass too much 
current, but from my memory of the A500 circuit, I can't think of any 
obvious candidate.

Have you tried running the machine with the cover off to see what is 
getting hot? It might be something as simple as a leaking decoupling 
capacitor.



[...]


> > My second computer was a TRS-80 Model 1 (my first,
> > FWIW, was an MK14, yes 
> > I still have both). I now have a Model 3 and Model
> > 4, and several CoCos. 
> > And schematics, etc for all of them.
> > 
> > -tony
> > 
> >  
> 
> Cool :)  Were you ever tempted with the Model
> 16 or 12?

I wish!. I'd love an Model 16, but they're not at all common in the UK, 
and would not be cheap (or easy) to ship from the States. In a moment of 
madness I did get a CoCo3 sent from the States (brand new machine, some 
16 years ago), but that was just the keyboard/processor unit, not a CRT 
monitor and drives too.

-tony