S100 address buss troubleshooting

Richard A. Cini rcini at optonline.net
Sun Jun 5 14:25:15 CDT 2005

Interestingly, in this unit, the front panel power switch is not used.
There is a jumper on the PC board which bridges the connector for the
switch. A new power switch was inserted in the back panel and wired
directly in the line.

About the UL listing, I thought it interesting how exposed line voltage
was. It's very easy to touch line voltage if you're not careful.


-----Original Message-----
From: cctalk-bounces at classiccmp.org
[mailto:cctalk-bounces at classiccmp.org] On Behalf Of Randy McLaughlin
Sent: Sunday, June 05, 2005 1:07 PM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: Re: S100 address buss troubleshooting

From: <shoppa_classiccmp at trailing-edge.com>
Sent: Sunday, June 05, 2005 11:49 AM

>> Be careful after turning off the computer and don't pull the cards 
>> until you are sure the voltage levels have dropped
> For that matter, if yours has a power switch on the front panel, be 
> careful what you touch in the vicinity of that switch, even after 
> you've turned it off!
> The rightmost switch was truly a "user wires it how he wants" switch, 
> and when you bought an IMSAI it came with artwork to let you make a 
> transparency layer that matched the function you chose.  (Which is why

> I find these arguments about keeping original front panel 
> transparencies so amusing.)
> Tim.

All of the S100 systems I've dealt with have had the line power exposed 
somewhere, none would ever pass UL testing.


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