Re: Pac repair using a chip comparitor

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I was guilty in my first month or so of servicing video games (back in the
70's) of plugging in a board while the power was on. This board had a
115VAC relay and, um, well..., it didn't survive the experience. This is
back in the days when Pong was a big deal (B&W of course!) and the games
sold for $4,000 (Yup, that's $4K Canadian, back then worth a bit MORE than
the US$) so I had to spend a week replacing all the IC's (ALL!) to get it
running again.

Now, of course, I never plug a part in backwards. Really.

"What Never?"

"No Never!"

"Well hardly ever..." (Gilbert & Sullivan)

Clay is right, it is hard to blame the part for our screw-ups, BUT I tried!
(running for cover now ;-)...

Happy Ho-Ho's!

John :-#)#

At 03:02 PM 12/12/00, Clay Cowgill wrote:
>I do find this a little silly. EPROMs will die if you plug them in
>backwards. PCB's will die if you reverse power and ground. This really
>shouldn't be any big news to anyone on this list... ;-) I do have an
>immediate solution that requires no modifications to the design though--
>Don't do that!
>
>I've sold lots of those 284's and 285's since 1998 and have had *maybe* a
>quarter of a percent of the total come back for repair (for *any* reason),
>so I'm really not inclined to modify my PCB design or hand-add a diode to
>every one. It's the 90:10 rule (or in this case the 99.75:0.25 rule :-).
>
>Kev's not quite right on one point though either-- they can be fixed just
>fine. I just have to do it... They're $7 each plus shipping if you smoke
>one.
>
>(I must confess that this really is perplexing to me. I mean, c'mon-- at my
>"real job" if my engineering technician complained that some part dies when
>plugged in backwards you can be pretty sure I'm not going to be blaming the
>part!)
>
>-Clay
>
>-----Original Message-----
>Date: Monday, December 11, 2000 8:06 AM
>Subject: Re: Pac repair using a chip comparitor
>
>
> >Mark's devices will die also if plugged in backwards...takes about an hour
> >or more to replace the IC's, same as the original...perhaps we could ask
> >both Mark and Clay to put in a 1N4005 diode across the Vcc and Ground so IT
> >shorts out if installed backwards and not the board...sort of a Silicon
> >Suicide device...
> >
> >John :-#)#
> >
> >At 11:16 PM 12/11/00, Kev wrote:
> >>http://users.erols.com/mowerman/bugtrap.htm
> >>
> >>pic & small write up of the Bugtrap.
> >>
> >>Word about Clay's most excellent products (Vram address or Sync bus), plug
> >>them in backwards & they die. There is no fixing these. Mark Spaeth
> >>produces a replica of the original boards with TTL components that are
> >>repairable.
> >>
> >>Personally I'm not too impressed with the Fluke 90 thingy, but maybe I
> >>haven't spent enough time with it yet.

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Received on Mon Dec 11 20:39:47 2000