28 Jan
2014
28 Jan
'14
9:25 a.m.
Just in reference to your comment on the caps.common mythology is once the caps blow,
that's it, board is gone.
I'm not got at electronics, don't know how true that is.
But it reminded me of another old related question,could you today, build a brand new 1541
with current parts?
I dont mean emulated like the SD drives or whatnot,I mean a real, functioning, exact 1541.
Is it still possible to buy a brand new 6502, 6520, IC ?(I did a quick search, but my
google-fu sucks atm)
Dan.
From: ard at p850ug1.demon.co.uk
Subject: Re: 1541 Alignment disk
To: cctalk at classiccmp.org
Date: Mon, 27 Jan 2014 19:57:04 +0000
Wow, I was just asking!
no need to bite my head off :)
I wonder about some of these "alignment" programs though.
You have to figure a few of them are just junk.
There was one that was only good for testing the speed of the drive,
you could adjust with a screwdriver. But that's all it did.
A lot of drives (I forget if the 1541 is one fo them) have a stroboscopic
disk on the spindle. You adjust the motor speed so tht this appears
stationy under mains lighting (there are nomally 50Hz and 60Hz patterns
on the strobe). Some yeats ago I built a device with a few counter ICs as
a divider chain to flash some white LEDs at eitehr 100Hz or 120Hz
(rememebr a mains lamp flashes twice per cycle). I designed it so said
LEds were on 1/16th of the time. The result gave the clearest indication
of when a drive was on-speed that I have ever seen.
[Drives dying]
Or how long before the caps on the boards go?
This is not a major problem. Capacitors are still made.
Eventually the c64 will be totally gone, left just to emulation.
DEC Vax systems are pretty close to the same state.
I've said before that there are really on 2 families of VAXen I would
consider running. The first s the 11/780, the second the 11/730. In both
cases almost all the aprts are either stil lavaialble or can be
substituted (they are docuemtned well enough to know what to repalce them
by).
Amigas are starting to be hard to find.
I used to be able to take apart and replace chips in c64s,
you could read the code and understand it.
with only 38k of ram usable (aprox) it wasn't hard to understand the whole =
system.
nowadays, forget it.
One reason I stick to my classic computers...
Raspberry pi seems to have potential in this regard.
Does it? The Rpi is based around a custo-ish IC in a BGA pacakage. Said
IC is not avaialble sperately, and solderign BGAs is not something that
can be odne with hand tools.
The instruction set of the graphics processor is not documented
(offiically). So forget understnadig nthe system.
And it's not a small machine. There's 112Mbytes of RAM in there. Programs
are large. Forget tryign to understnad them all.
-tony