A few Williams questions

DarrenF

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1) I've got 5 or 6 Williams CPU boards, Rev - thru Rev D, and none of them have the little "levers" on the 40-pin connector for the ROM board. This makes it a bit of a PITA to pull that connector out; I'm worried about damaging the crumby-by-design IDC connection. Did they all get broken off over the years, or did Williams ship them without the removing levers installed?

2) Does any replacement or source exist for the "Special Chips" on Robotron & Joust ROM boards?

3) Does anyone know a Mouser or Digikey (or other major supplier) part number for the 20-position IDC connector that solders to the widget boards? I haven't encountered that specific type of connector until these Williams boards...
 
1) I've got 5 or 6 Williams CPU boards, Rev - thru Rev D, and none of them have the little "levers" on the 40-pin connector for the ROM board. This makes it a bit of a PITA to pull that connector out; I'm worried about damaging the crumby-by-design IDC connection. Did they all get broken off over the years, or did Williams ship them without the removing levers installed?

2) Does any replacement or source exist for the "Special Chips" on Robotron & Joust ROM boards?

3) Does anyone know a Mouser or Digikey (or other major supplier) part number for the 20-position IDC connector that solders to the widget boards? I haven't encountered that specific type of connector until these Williams boards...

Hi Darren.

(1) Williams saved approximately $0.29 per board by not including the levers on the 40 pin connectors. I have sent about 29,000 curses to the pinhead in the accounting department that approved that decision. :mad:

On the other hand, the life expectency of these boards was about 2.5 years and they were never supposed to be separated, just thrown away.

(2) Yes and No. Rumors have abounded for years about rogue electrical engineering geniuses that have reverse engineered these chips onto FPGA daughterboards. To date, I have yet to see one of these (with the exception of JROK's multi-Williams board that has them embedded in the hardware emulation). The best source for these chips is other ROM boards that are damaged in other ways.

(3) Digi-Key has replacements for the 20 pin ribbon cables (part number C3PPS-2018G-ND). This is an 18 inch cable with solder connectors on both ends. Cut it in half and you have 2 cable assemblies ready for installation.

They also have 40 pin ribbon cables (C3PPS-4018G-ND). These are also 18 inch cables with connectors on both ends.

If you just need the solder connectors, the part numbers are: CPC20S-ND and CPS40S-ND for the 20 & 40 pin connectors repectively.

I have not ordered the connectors by themselves but the pictures and the specs look like the exact replacement parts.

ken

EDIT: BTW, the safest way to remove the ribbon connectors is to use a small flat bladed screwdriver. You slide it into the part where the cam lifters would be, dig one corner into the side of the connector and lift it slightly so that it is loose. Repeat on the other side, alternating sides until the connector is loose and can be safely lifted without putting strain on the ribbon cable.
 
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Slight correction

If you just need the solder connectors, the part numbers are: CPC20S-ND and CPS40S-ND for the 20 & 40 pin connectors repectively.

That should be CPC40S-ND for the 40 pin solder connector (typo :)
 
(3) Digi-Key has replacements for the 20 pin ribbon cables (part number C3PPS-2018G-ND). This is an 18 inch cable with solder connectors on both ends. Cut it in half and you have 2 cable assemblies ready for installation.

They also have 40 pin ribbon cables (C3PPS-4018G-ND). These are also 18 inch cables with connectors on both ends.

If you just need the solder connectors, the part numbers are: CPC20S-ND and CPS40S-ND for the 20 & 40 pin connectors repectively.

I have not ordered the connectors by themselves but the pictures and the specs look like the exact replacement parts.

ken

EDIT: BTW, the safest way to remove the ribbon connectors is to use a small flat bladed screwdriver. You slide it into the part where the cam lifters would be, dig one corner into the side of the connector and lift it slightly so that it is loose. Repeat on the other side, alternating sides until the connector is loose and can be safely lifted without putting strain on the ribbon cable.

Thanks for the information and tips, Ken.
 
[for some reason the POS forum software gives an error when I tried to post the whole thing at once, so this is continued... in multiple posts]
 
I found individual cam levers on Mouserr (p/n 571-1023122, among others). I wonder if they're universal enough to fit into the original housings on Wms boards?? It'd be much nicer to just snap in a pair of them than change out the whole connector.

I tried removing the connectors they way you described, but somehow was unsuccessful. Anyhow, trying again (knowing that you said it works ;P) I get them out fine. Much better than pulling on the cable (I hate doing that).

A couple new questions:

(4) I like to cut the jumper (trace, actually) to change the sync from positive to negative. (My test bench monitor accepts either pos or neg sync, but with positive the image is offset to the left.) Do most people want them original (with positive sync) or modified (as I do) to provide the more-common negative sync? Trying to determine if I'm better off leaving them as-tested, or re-solder that jumper before selling...

(5) About battery holders: It seems that all the cool people are removing the OEM battery holder and installing a lithium coin-cell holder. I've got a couple with the battery holder still in-tact and uncorroded. I'd rather not yank off a perfectly good battery holder, so I'm thinking of just installing Lithium AA batteries. Any down-side to this I'm not thinking of?

[that's wacky. with the word "Mouser" in the post, I get an "access forbidden error". Mis-spell it, and it works fine...]
 
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(4) I like to cut the jumper (trace, actually) to change the sync from positive to negative. (My test bench monitor accepts either pos or neg sync, but with positive the image is offset to the left.) Do most people want them original (with positive sync) or modified (as I do) to provide the more-common negative sync? Trying to determine if I'm better off leaving them as-tested, or re-solder that jumper before selling...

In my experience, people like the boards to be original. If they are modded for negative synch, then the video cable of the harness needs to be rebuilt. That tends to be more than most people are interested in doing.

A less permanent solution is to build a sync inverter. A simple self powered one can be build using 2 diodes, a capacitor and a 74C04 chip:

picture.php


If you build this into an adapter, then you don't need to mod the boards.

(5) About battery holders: It seems that all the cool people are removing the OEM battery holder and installing a lithium coin-cell holder. I've got a couple with the battery holder still in-tact and uncorroded. I'd rather not yank off a perfectly good battery holder, so I'm thinking of just installing Lithium AA batteries. Any down-side to this I'm not thinking of?

All AA batteries will outgas slightly. It is the outgassing that corrrodes the boards. Everyone talks about the batteries leaking and dripping on the boards. Did anyone every notice that the batteries on Williams boards are in the lower left corner whan the boards are normally mounted? So how do they drip up?

ken
 
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In my experience, people like the boards to be original. If they are modded for negative synch, then the video cable of the harness needs to be rebuilt. That tends to be more than most people are interested in doing.

Makes sense. I'll bridge them back to positve sync with solder.

All AA batteries will outgas slightly. It is the outgassing that corrrodes the boards.

I'm referring to lithium AA batteries, like this:
51vllkm2EML._SL500_AA300_.jpg


Are these somehow chemically different from coin-cell lithiums like this?
batteryfront.jpg
 
Makes sense. I'll bridge them back to positve sync with solder.



I'm referring to lithium AA batteries, like this:
51vllkm2EML._SL500_AA300_.jpg


Are these somehow chemically different from coin-cell lithiums like this?
batteryfront.jpg

Never looked into the chemistry, but the mechanical process of sealing the batteries is much better in the button cells. They are designed for electronic circuits. The AA cells are larger and present more potential for one oof the seams to split.

I used to use the same AA batteries until I went to replace them in one of my games and found that one has split and corroded the battery holder and there was some corrosion on the nearest chips.

Now I put CR2032 cell holders in all of my boards.

ken
 
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