Re: Slots not working

[Rubywand <rubywand@swbell.net>]

Supertimer writes ...
> 
> I had a ROM 1 GS motherboard which worked fine except the slots
> did not work.  When a card was plugged in and the control panel was
> set to YOUR CARD, the slots were still seen by the GS as empty.
> ALL the slots had this problem EXCEPT the memory expansion slots.
> What was wrong with this motherboard?


    If you are saying that, whatever the card and whatever the Slot, the
cards plugged into the GS's Slots did not work, then, there are a few
halfway decent suspects on a GS that, otherwise, seems to work okay:

 1. A break in the trace which is supposed to supply +5V to each Slot
card would shut down nearly any Slot card.  

 2. Most Slot cards need to receive and/or send information over the
Slot Data bus. A defective 74HCT245 (IC UF2) or one with a loose/broken
pin connection would be likely to kill Slot Data bus transfers.

 3. A defective Slotmaker chip (IC UE11) or one with a broken trace on
any of several inputs would render most Slot cards non-functional.

 4. A break in any of several traces supplying signals to the Slots
would disable many Slot cards.

 5. Many Slot cards would not work should any of several Slot traces be
shorted to another trace or to ground. (Sources of shorting include bent
case shielding below or behind the motherboard, a Slot socket into which
a shard of metal, solder, or bit of wire has fallen, a shorted bypass
capacitor, and, possibly a Coke, etc. spill leaving conductive residue
beneath several Slot sockets.)

 6. If a defective Slot card is plugged into one Slot while other Slots
are being tried with other cards, the defective card could short or
corrupt critical bus lines and render other cards non-functional.


Rubywand