Re: Pac repair using a chip comparitor

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.
Received on Mon Dec 11 20:09:51 2000