Re: SecondSight boot stability

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

In article <4vn17s$rtq@newsbf02.news.aol.com>,
RUBYWAND <rubywand@aol.com> wrote:

>     That depends on your alternatives. If your GS is bombing regularly
>and your setup fits the "power supply problem" profile, then _someone_
>needs to do a fix. Maybe the local Apple Users Group could have a Power
>Supply Fix meeting. Those familiar with the work required could guide
>users through the motherboard and PS leads mods and check their work along
>the way.
>
>     Regarding the motherboard additions: Most likely, nobody especially
>likes to remove all cords and plugs, remove the Power Supply, pull out
>cards, pop out the motherboard-- be sure to undo any hold-down bolts or
>nuts-- and do mods. (Also, be sure to mark/label boards & cords and keep
>notes of what goes where!)

Labeling usually isn't a problem.  Apple has labeled most of the cables
for you.  The things you'll need to label (and then only if you don't
know what goes where) are the things attached to the serial ports,
and the things attached to internal cards.


<stuff deleted.  note:  pins 25 & 26 on the slots are toward the BACK
of the motherboard.  if you do it wrong, you fry it.>


>     Check out the empty case. You will get some idea of where supports
>crop up to hold the motherboard. When connecting wires from the PS
>connector to Slots 3 and 7, remember to leave enough slack to route around
>the supports.

Leave no slack - the big rule of motherboard mods.  Your wires should be
insulated, with no more insulation stripped off than absolutely necessary
for attaching to the solder points, and the routing should be within
a 1/16" of an inch to the motherboard.  That way it won't catch on
anything and pull itself out, it won't look terrible, etc.  The
things you need to worry about routing around are the soldered-in
pins on the motherboard.

>     Using a pencil type soldering iron (approx. 25-35 watts) and good
>quality solder (like Kester "44)  connect the wires. Avoid using wire with
>very thin insulation. It helps to use color-coded leads-- like Black for
>GND, Red for +5, and Orange for +12. Run separate leads from the PS
>Connector points to each Slot.

The "quality" of the solder shouldn't be nearly as important as the
metal ratio.  My off-brand light-gage 60/40 worked fine.  I'm not sure
what ratio solder was used on the motherboard originally, but that'd
be the stuff to use.

>     Regarding the Fat Power Supply leads mod, as Will Baguhn suggests,
>#14 gauge copper is probably heavy enough and it is easier to work with
>than #12 gauge. (Someone who has done a fair number of linear PS designs
>tends to go for the heaviest gauge that can be bent into place.)  Whether
>#12 or #14, try to get stranded stuff for the PS leads. It is easier to
>position without having to worry about twisting and breaking loose from
>the PS circuit board.
>
>
>Rubywand

Another thing to remember when choosing your wire for the "Fat Power
Supply" leads is that solid wire can definitely carry more current
than stranded.  Obviously, it's your computer and you can do what
you want, but 18# solid worked fine for me (under the motherboard).
I was crashing on my Zip 12/64s for a while, but after adding this
wire (+5) to the Zip slot (3), everything works fine.  I didn't need
to add power to the RamFast (7) to make it work.

Stranded wire may be enough for the fat power supply leads, but on the
bottom of the motherboard, solid should DEFINITELY be used.  It doesn't
need to be flexible, and it does need to carry current.

Of course, your mileage may vary.

-- 
                                      --- Rev. SPQR (wbaguhn@nyx.net)
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