I bought a couple of these WPC MPU bare boards on http://pinball.center... they seem to be pretty close copies of the original board, even down to the grounding contacts at the bottom, which the Two-Bits boards don't have. Thought I'd mention it, if anyone's looking to do a build. It was a pain getting them here, had to be shipped through Mailboxde to the US. Their 8-driver boards are similarly good copies. I wonder if patents/licensing are why they can't ship direct.
Here's the assembled board, nearly identical to the Williams board. A few minor improvements some might not notice, like the bigger capacitor and the newer HC chip logic rather than the LS logic that Williams shipped in the 90s. Also a dip switch bank and what seem to be better quality diodes. They work great in the games I've tested with. No issues whatsoever.
Scratching my head trying to figure out why you would go to all that trouble to assemble a new board and then put a battery holder on it? I can understand wanting a working clock (no NVRAM) but at least do a remote mounted battery pack! (assuming you are not using the wood dowel approach?)
Honestly not worried about it. Change batteries every year and there won’t be a problem. Most leaks have happened by machines sitting unmaintained for years.
It is an incredibly unwise idea to use alkaline batteries. They can leak at any time.
The first thing I do on any game is get rid of those ticking time bombs.
NVRAM is cheap these days.
Never had an alkaline leak on me. Change frequently. Don’t use cheap junk. Don’t store in extreme temperatures. Watch for swelling.
Anyway this thread is about the boards not my choice of battery.
Quoted from jzdziarski:Never had an alkaline leak on me. Change frequently. Don’t use cheap junk. Don’t store in extreme temperatures. Watch for swelling.
Don't use alkaline and you won't ever have to worry about checking them or changing them ever again.
Quoted from jzdziarski:Anyway this thread is about the boards not my choice of battery.
We're trying to save your brand new board from potential damage.
Quoted from jzdziarski:Never had an alkaline leak on me. Change frequently. Don’t use cheap junk. Don’t store in extreme temperatures. Watch for swelling.
Anyway this thread is about the boards not my choice of battery.
If this thread is about the boards, your decision to keep batteries on the brand new MPU is overshadowing anything else unfortunately :/
Quoted from jzdziarski:Starting to believe what people say about this forum. Complete waste of time.
Sorry to hear you feel that way. 
Quoted from Pdxmonkey:Doesn’t Pinball.center not ship to USA?
Nope, not any more. They stopped doing it a year or two back.
OP nice job on assembling them and don't feel bad about the responses. After people get an expensive pcb ruined by leaking batteries they take a hard position on using nvram.
I deliberately made 6264 sram not work on (with ce2) on the replacement bally mpu =D.
For what it's worth only the asic and the crystal circuit needs batteries to keep time. The 6264 sram does not keep the real time clock.
Quoted from barakandl:For what it's worth only the asic and the 32mhz crystal circuit needs batteries to keep time. The 6264 sram does not keep the real time clock.
To the OP (even though he/she is gone now), sorry to have caused more criticism that positive vibes!
Quoted from CactusJack:. As I recall, the problem is, with battery power applied to the ASICs chip, there is power that gets to the Vcc pin of the 6264 due to the clamping diodes on the inputs (and the pull ups on CE and WE). Therefore, a NVRam module never goes into standby and drains the battery source (battery, coin cell, super cap). So, you might as well use a CMOS ram.
To the OP (even though he/she is gone now), sorry to have caused more criticism that positive vibes!
The FM16W08 has a low power standby mode. Granted it probably not as a low power as a SRAM standby, but I'd imagine if the SRAM goes into standby, the FM16W08 would too.
Im thinking a complete oscillator circuit instead of discreet so that inverter chip for the RTC crystal circuit does not need battery voltage. Put the NVRAM on the main VCC and tie P26 to high (neener). Then you just need to worry about the asic and the four pin cystal can being hooked up to the batteries. I think they make 32khz complete oscillators in super low power specifically for battery backed real time clocks.
Quoted from Ericpinballfan:Suspicious duplicate account. Cross checking things with his TZ playfield ad, things dont add up on this.
Just as well hes gone now, well, ended this name. Hes here, but who is he...hummmm?
For being so thin skinned, my suspicion was the post was purely to promote the sale of the boards.
Fraud alert!
Wow this is so stupid it's funny. This guy buys two boards from me which were fully tested & packaged using antistatic protocol by me. He receives two boards with no damage to the package & complains that I used pink bubbles that aren't antistatic. We send the website info to him to confirm they are designed for protecting static sensitive devices, he then says the boards aren't static sensitive. He installs one board & it's fine, he installs the second board & the +5 led won't even light. He starts trashing me on Ebay & Pinside regarding this. I request pics of the board through Ebay to see if I can spot the issue as I always supply tech support if the customer has an issue. I spot that the lower mounting screws have cut through the solder mask & have grounded the +5 volt plane on the board. This won't damage the +5 volt regulator as it has overload protection, but it will stop the board from operating. I mention to him to release those screws & try again, he says he tried that with no change & escalates with Ebay. Ebay takes about $600 out of my Paypal account & puts it on hold. At the same time as all this he also builds boards from overseas. He then takes parts from our board, installs them in his board & posts them here on Pinside. He was supposed to ship one board back to me in Canada with tracking, he shipped something a few days ago & uses my Canadian address & my US postal code when my address was clearly marked on the package he received. I don't think I'll ever see my board back which I offered to repair & return at my expense or my $600US. It sucks to have over 3800 positive feedback & get a negative from a person with 0 feedback. Ebay did favor him in this dispute when I did everything possible to fix the problem. I will update the description on my auction & supply Nylon screws to avoid this issue in the future.
Hopefully this guy doesn't scam anyone else!
Cheers,
Dave (Linkpete on Ebay)
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