Re: SecondSight boot stability

[wbaguhn@nyx10.cs.du.edu (Will Baguhn)]

In article <4v5ooi$318@newsbf02.news.aol.com>,
RUBYWAND <rubywand@aol.com> wrote:
>In article <32160EF8.6855@Carver.agn.net>, Bill Carver
><Bill@Carver.agn.net> writes:
>
>>
>>Before you blame the second sight card, check your power supply.
>
>     When SS is the only Slot board, it seems less likely. Still, SS is
>said to place a significant demand on the +12V line. This could produce
>enough voltage drop across the skimpy +12V power supply lead to induce
>noise which could bomb the system.
>
> 
>>They're dropping like flies now.
>>-- 
>
>     True; and, really, it's too bad. There is good reason to believe that
>"power supply problems" are, mainly, power supply lead problems. As long
>as most users were running at fairly small loads, the power supply looked
>fine. When we started to add hot accelerators, RamFAST's, and Second Sight
>boards, the power supply suddenly "went bad".
>
>     Our Woz IIgs is one of the first two sold in Houston back in 1986. It
>has the original power supply and works fine loaded with the usual
>accelerator, RamFast, Focus Hard Card, etc.. Its power supply "went bad"
>when we added the 10MHz Zip-GS. Fattening the PS +5V and GND leads cut
>glitching significantly. On the motherboard, adding #16 gauge wires from
>the +5V and GND PS connector pads to +5V and GND points on Slots 3 and 7
>finished the job. (Second Sight board users may need to fatten the +12V
>lead, too)  Anyway, no glitches-- the power supply "went good".
>
>     The standard IIgs power supply is rated at 4 Amps (+5V); but, due to
>skimpy leads, cannot actually run a system which pulls more than about
>2.5A on the +5V line. At around 2 Amps, the voltage drop from PS to
>motherboard starts to be significant in terms of noise spikes. At higher
>loads, the at-motherboard voltage edges downward; noise levels increase
>and noise immunity decreases.
>
>     Swapping in a new "heavy duty" supply may, sometimes, fix glitching
>because the leads happen to be a bit heavier and/or shorter. The new
>supply may run at a slightly higher voltage, too; and, perhaps, the new
>supply comes with a gold-plated plug. (Sometimes, especially when the load
>is fairly heavy, a new PS will merely reduce glitching or make no great
>difference.)  Users are unlikely to find a replacement unit which tackles
>the problem correctly-- i.e. the leads (at least +5V and GND)  need to be
>'really fat'.
>
>     Basically, most "bad" IIgs supplies are, probably, just fine.
>However, the skimpy PS leads are a humongous design flaw and should be
>replaced. (A very nice cure would be to use #14 gauge silver going to a
>gold-plated plug.)
>
>
>Rubywand

Otherwise, 14 gauge solid copper wire is readily available as a
standard electrician's size.  It should work just fine; the difficulty
being "how do i get the stupid power supply connector on there?"

(ps: anyone know an AMP part number for the power-supply side of the
IIgs power supply connector?  thanks)
-- 
                                      --- Rev. SPQR (wbaguhn@nyx.net)
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