On Fri, 21 Aug 1998, Tony Duell wrote:
> Torx screws are turning up in all sorts of computer stuff, including
> classics. Printers, disk drives, tape drives, laptops, etc, etc, etc all
> need Toex drivers to dismantle them. So you may well find a complete set
> a useful thing to get.
Yes, I can see why a complete set might be useful. But does a regular set
that one would buy at the local hardware store have the extended length
Macintosh-opening driver?
> > [re: logic probes]
> >
> > I just bought a 'cheap' Radio Shack logic probe today, also 10MHz.
>
> Sounds like the same one I used. Plenty good enough for 90% of the
> computers you're likely to work on.
I think only two of the 35 (? <-- I've lost count again already) machines
in my posession have _processor_ clocks faster than 10MHz, so it should do
fine. :)
> > Unfortunately, tonight I was powering it with a cheap Radio Shack power
> > adapter, and it was screetching and had the PULSE light on no matter where
> > I made contact. So probably I need a power supply with better filtering.
>
> If it is the same one, that's a sure sign there's ripple on the power
> supply.
What is 'ripple' on the power supply? :)
> > Anyway, I don't know what the heck I'm doing with this thing yet. But
>
> Learning to use one properly, and interpret all the indications, is quite
> hard. Do you have a simple computer with schematics? (something like an
> Apple ][ would be ideal).
Unfortunately my ][+ clone is quite ill, and is in increasing need of
medical help. But I do have the VIC-20 and Commodore 64 schematics, too.
I think there may be a few errors on the schematics, and those machines
have a few custom parts, but I may as well play with those machines as
anything else.
When I bought my very first VIC-20, back in 1990, it was my intention to
tear it apart and learn something about electronics with it. It was in a
smashed up case and looked rather forlorn, and I think there was a metal
screw or two that had found their way into the case. But when I got it
home, the darn thing worked, and I got hooked, and I didn't want to do
anything to harm my little VIC. :)
That was the machine that started my 'collection'. The first machine that
I had bought as something just to have around, to play with, etc, instead
of as my main computer.
Now I have three VIC-20s, and that original VIC is definitely in the worst
shape of the three. It has a damaged cartridge connector and it now lives
in a Commodore 64 case. So I may as well haul it out and use it for my
originally intended purpose.
> Start by looking at the CPU clock signal, and the address and data buses.
> Get to know what normal activity looks like. Look at some I/O select
> signal (that C400 strobe on the games connector of an Apple ][ would do).
> Run a program to trigger that, and see what that looks like. Etc.
>
> The idea is to look at as many known signals as you can and see what the
> logic probe shows.
Yeah, neat. I don't know how "known" any of the signals will be, though.
:)
> > I also did a very dumb thing today in that I bought the wrong connectors
> > for the Mac->Amiga mouse cable I wanted to build. I bought one of each
> > sex, which any lame-brained dimwit would recognize as wrong as the two
> > machines in question use ports of the opposite sex.
>
> Ooops...
>
> Another tip. Whenever I buy low-cost/common components - like D
> connectors, resistors, capacitors, TTL chips, etc, I always buy a few
> more, and a few related ones.
These were common, but definitely NOT low-cost! I didn't bother to find
out how much they were until after I had already paid for them (dammit!).
The prices weren't on them, only bar codes.
Something which I think should be illegal.
Most of the computers in my collection cost me less than those two 9-pin
connectors. (The connectors were about $5 each!)
> If I think I need the plug, I'll buy a socket as well. If I think I
> need an AND gate, I'll get a NAND and an OR as well. In no time at all,
> you'll have a box of oddments for fixing machines, trying hacks, etc.
I'll have to find an INEXPENSIVE source of parts before I do that.
I know of one place that is considerably less expensive than Radio Shack,
but it's much more expensive in time. It takes me about two hours to get
there by BMW (Bus, Metro, Walk).
A lot of their parts are surplus or recycled (pulled out of murdered
VIC-20s and stuff).
> -tony
Doug Spence
ds_spenc_at_alcor.concordia.ca
http://alcor.concordia.ca/~ds_spenc/
Received on Sat Aug 29 1998 - 02:27:53 BST