At 23:25 12/01/2003, you wrote:
> > >That figures... Maplin rarely have useful components in stock in the
> > >shops any more. They were out of stock of 10k resistors one time I needed
> > >them.
> >
> > They seem to have really gone downhill in the last few years; I suspect
> the
> > passing of Tandy has something to do with this - why should they care,
> > there is no national competition. :(
>
>I heard a rumour (nothing more) that Maplin were now (part?) owned by the
>old Tandy. Which probably explains why they now sell lo-fi, etc.
Dunno about that, I know Tandy were subsumed into Carphone Warehouse, maybe
Maplin got the cheapo hifi bit?
> > >I am trying to work out why your soldering iron was not on your bench
> > >where it should have been. Unless you had taken it somewhere for a field
> > >repair, of course.
> >
> > Sad to say, I don't do anything like enough electronic
> > assembly/disassembly. This is only the second time I've used the iron
> since
>
>I don't do that much programming, but I know where gcc is :-)
Yeah, but gcc lives on the computer, thus the furthest away it can ever get
is a few button presses... My soldering iron (& assorted accessories) seem
to have a life of their own, and find their way into all sorts of places...
> > tried it again this morning the screen is just blank. I know the video
> side
> > is OK, as if you let the tube warm up, then power cycle it, you get the
> > garbage characters for a second or so, then it clears to blank. I've
>
>Well, that means the CPU is running, and that it can access memory (and
>that at least osme of the ROM is good). That's a step forward, surely...
Definitely. I tried it with a couple of 3rd party ROMs out, but neither
made a difference, so I don't think they're part of the problem. Or, if
they are, it's an upstream problem to the one that's currently afflicting
the machine. My further assumption is it's definitely a bit of silicon
that's gone wrong, rather than anything on the power side.
Unfortunately, I still don't have an EPROM burner/eraser, so even if it is
a ROM that's gone funny, I can't do anything about it yet. Any ideas for a
suitable model of device - ideally one which is relatively easy to use, can
burn different sized packages, and will connect to a Windoze PC easily?
> > re-seated all of the smaller chips to no avail; will try the big chips
> > tomorrow, after that it's a crash-course in microelectronic diagnosis.
>
>I've had _many_ problems with bad IC sockets in PETs. I'd replace the lot
>with turned-pin ones (I doubt Maplin still do these, if they do, they'll
>never have them in stock, but RS and/or Farnell list them).
I have an RS account, I'll probably get 'em from there - Farnell seem to
charge some fantastically high prices for some of their stuff (e.g. 24-way
1.156" PCB edge connectors for ?17.00 each). Is there any mileage in
getting a gas soldering iron with an IC block (i.e. one of those things
which solders/desolders all pins in a socket at once), or will I be OK with
my regular electric iron & a vacuum desolderer?
>[6 pin DIN plug]
>
>Clean the pins with a contact file or (fine) wet-n-dry paper before you
>start...
Makes sense...
> > won't grip, and you end up melting a pin right through the plastic. Grr. I
> > mean, all they have to do is make the plastic bit out of bakalite -
> problem
> > solved.
>
>Or PTFE (which won't melt with a normal soldering iron). Or the
>glass-fibre PCB material -- I managed to get some DIL headers that were
>made of PCB substrate with pins inserted, and they were by far the
>easiest to use of all I'd tried. They did not melt when soldered. Pity I
>can't get any more...
Presumably they'd only be useful for hobbyists, and perhaps too expensive
to be mainstream. Annoyingly, about 8 years ago I could have purchased a
complete industrial PCB production line, c/w solder baths, plating line,
etc., for about ?5000. Unfortunately, not only did I not have ?5000, but I
had nowhere to put it either. I can't help but think that solder bath would
have been quite useful for removing IC sockets & the like...
Mind you, I did get the PCB drill; a micromat CNC machine. One day, I'll
put it all back together, at least I can drill my own PCBs then...
[Fireball 3040]
> > Hmm. It's presently unidentifiable (just a black smear on the circuit
>
>Sounds like a tantalum...
Righto.
> > Thing is, did the tantalum cap blow because it was old, or because
> > something else was awry?
>
>Most likely because it's old. It was probably a supply decoupler. I've
>had the odd one on a PCB explode, and the rest remain OK. No simple
>electrical problem could cause that.
That's what I was hoping you'd say :)
>Have you tried the 3040 (after removing the remains of the capacitor). It
>wouldn't suprise me if it still worked!
Hmm, I'll give that a shot this afternoon I think.
Cheers Tony - all useful stuff again! And you'll make me an electronics
hobbyist yet :)
--
Cheers, Ade.
Be where it's at, B-Racing!
http://b-racing.com
Received on Mon Jan 13 2003 - 01:26:00 GMT