Re: Second Sight "jumping" picture

[rubywand@aol.com]

In article <32ea8d33.3538268@PersonalNews.Germany.EU.net>,
sbehrens@arrowweb.com (S�nke Behrens) writes:

....

>>     Adding #16 leads from the power connector +5 and +12 solder points
to
>>the SS Slot +5 and +12 points will reduce noise. A couple .45uF 20V disc
>>caps (one each from the Slot +5 and +12 points to ground) will add
>>bypassing near the SS and further reduce noise. These steps may
eliminate
>>the shifting.
>
>OK, I'll give that a try. What about GND? Should I run a line to it as
>well? 

     Yes. The last time our motherboard was removed-- when replacing the
Slot 3 socket-- I made a sketch of the mod wiring. It shows that short
leads (#16 or so wire) are run from the Ground pin of Slots 3 and 7 to the
Ground plane near the back of the motherboard. A fairly heavy lead (e.g.
#14 or #12) runs to this Ground plane from the Power Supply connector
Ground point. 

     Be sure to route all leads to allow easy replacement of the MB. You
do not want a lead to block a mounting hole or get in the way of a support
from the case bottom.

     This is, also, a chance to get rid of the metal shield on the case
bottom. It gets in the way of mods and, really, seems to have no affect on
R-TV interference. (You can scrap the case lid shield, too. You will find
that it is much easier to remove and replace the lid, air flow is better,
and, the lid is easier to clean.)

 
>And what about the lines from the power supply to the board ...
>that runs partly still over the old lines of the GS supply (couldn't
>find a matching connector for the board).
>

     The old GS Power Supply lines are _too small_ for +5, +12, and
Ground. These three leads carry enough current and are skimpy enough to
act like resistors. The new PS +5, +12, Gnd leads should go directly to
the plug.

     One at a time, remove each lead with pin attached from the PS plug.
(You need to press on the pin though a slot in the plug with a small
screwdriver. This pushes up a retainer and allows the pin to come out.) 
Remove the weaky +5, +12, or Ground lead and directly solder on the heavy
duty lead from the new supply. (If you have just one Ground lead,
splice-in the weaky lead coming from the other Ground pin and cover with
shrinkable tubing.)
 

>>     Something else to check are socketed IC's and a socketed clock
>>oscillator module-- are there any on the SS?-- which may be making a
poor
>>connection at one or more pins. (Scootch-up and re-socket any socketed
>>IC's and modules.)
>
>There are two ... a Lattice FPGA and an EPROM. I didn't remove the
>Lattice (it's PLCC), but pressed both of them in more firmly. Didn't
>solve the problem, though.
>

     Just pressing down won't do the job. The idea of scootching-up and
re-socketing is to break up any micro-thin coating which may be messing up
the connection. 



Rubywand