Resetting C= machines with non-standard implements (was Re: Are you sure the 6550 is dead?)

From: Paul Thompson <thompson_at_mail.athenet.net>
Date: Wed Mar 22 19:30:57 2000

I had a C64 on which I installed a reset switch into my HES-MON assembler
cartridge. I used it for several years that way. I eventually gave the
64 to my nephew and I believe the machine still works to this day,
although I doubt the HES-MON got much use after I gave it away.

I did manage to fry a couple of sound chips, probably by feeding too many
nasty signals through the (band-pass?) filter input on the sound DIN.

In college I picked up a discarded Televideo 950 terminal with a 6502
processor. It had a habit of hanging on invalid escape codes, so I
soldered a momentary push button switch on its reset pin. It also
continued to work up to being discarded.

The capacitor probably would have been a good idea in either case.

Paul


On Thu, 23 Mar 2000, Tony Duell wrote:

> >
> > Quite, I've got to say this is an EXTREMELY BAD way of resetting a C64 in my
> > experience.
>
> Yes, but I would have thought that the main problem is that you're
> effectively shorting an output (namely the output of the chip that
> normally generates the reset signal) to ground. This is not generally a
> good idea.
>
> I am suprised it was the processor that failed, though. AFAIK, the
> processor in a C64 never outputs anything to the reset line.
>
> There's a fairly easy modification IIRC that adds a reset switch in
> parallel with a capacitor in the reset circuit. This is a safe way to do
> it. It's fairly obvious how to do this given a C64 schematic. If anyone
> is seriously interested, I'll see what I can find.
>
> -tony
>
Received on Wed Mar 22 2000 - 19:30:57 GMT