Hi, I'm new...

[aliensrcooluk at yahoo.co.uk]

 --- Tony Duell <ard at p850ug1.demon.co.uk> wrote: 
> > 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 (rathe
r
> 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. 

errr... no voltimeter here, nor do i have a clue
where to buy one from (or how to use one).


> 
> [...]
> 
> > 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 syste
ms
> that have worked 
> without a good reason.
> 

I still have the old A600 PSU, I usually keep
faulty/suspected faulty parts for spare parts.


> > 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 fault
y
> resistor could upset 
> the biasing on some other component, and thus caus
e
> that to pass too much 
> current, but from my memory of the A500 circuit, I
> can't think of any 
> obvious candidate.
> 

Ahem, it's an A600 I own ;)


> 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.
> 

I was planning too, but I had concerns about
being electricuted (spelling?) as I had never
done that before, and also becuase of the 
recent hot weather - I have no patience in 
hot weather and feared running it in the
extreme heat would only cause more damage.

What would the "leaking decoupling capacitor"
look like, if that was the cause?

Which is the capacitor? Anyone know?


> 
> 
> [...]
> 
> 
> > > 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
> 
>  


Probably best you didn't get the 16, as it's
inferior to the 12!
The 12 was actually made later than the 16
and supports various modes making it
compatible with 16 and 4 (?) software
(and hardware?). Infact I think the Model 12
was the best of the bunch.


Regards,
Andrew B
aliensrcooluk at yahoo.co.uk