Re: WPC Resets - flipper activated
- From: "GPE" <See_my_website_for_email@xxxxxxx>
- Date: Thu, 8 Jun 2006 21:53:32 -0500
"John Wart, jr" <johnwartjr@xxxxxxxxxxxxxx> wrote in message news:jMadnUecpozkXBXZnZ2dnUVZ_oidnZ2d@xxxxxxxxxxxxxx
I'm trying to track down a reset problem on a game I have. It's getting annoying. Game is I500.
Power driver has all new bridges and caps as well as jumpers per Clay's guide.
When the game resets, the +5 does not budge. It stays solid at 4.8.
I've replaced flipper coils (were wrong value anyways). I've swapped the fliptronics board, as well as the DMD driver. I even tried another set of opto boards. The voltages at all test points and at the DMD are good. For the heck of it, I tried a new CPU ROM, too.
Sometimes, if the game sits in attract mode, it won't reset immediately - but if you beat on the right flippers enough, it does eventually reset.
Anyone got a clue? I'm frustrated with it to the point where I let it sit for awhile, will likely dig back into it this weekend.
Thanks!
--
http://www.myhomegameroom.com
The 4.8 volts is within the specs for that regulator as well as within specs for all IC's on that board (but not by much). The MPU's reset generator (MC34064) resets when the voltage is about 4.6 volts (or as much as 4.7 volts) - so there isn't much leadway here. You probably see a slight flutter on the voltage when you hit the flippers - just enough to hit the reset generator's threshold.
The Williams +5V supply is a classic example of how NOT to design a +5V supply. *If* they would have left room to insert a forward biased diode between the voltage regulator and ground - you could have raised the regulator threshold by 0.5-0.7 volts. But, alas, they didn't allow for this.
You could try to reduce the reset generator threshold voltage by replacing it with something such as the MCP130-450DI/TO. This would drop the threshold down by a tenth or so of a volt (~4.5 volt threshold).
Or you can try replacing the LM323K. The LM323K has a 5% accuracy (which -should- work in most situations). But, if it is on the lower side of that spectrum - you will see something as low as 4.75 volts and still be within spec. Can try an LM323AK -- has a low end of 4.85 volts. The LM323AK's cost considerably more than the standard LM323K. Or maybe the combination of lower threshold reset generator plus a tighter tolerance voltage regulator my be the fix in this case.
Good luck,
Ed Krzycki
Great Plains Electronics
www.GreatPlainsElectronics.com
.
- References:
- TECH: WPC Resets - flipper activated
- From: John Wart, jr
- TECH: WPC Resets - flipper activated
- Prev by Date: Re: WTB: ROLLING STONES BG/thanks!
- Next by Date: Re: TECH: FH wire identification
- Previous by thread: Re: WPC Resets - flipper activated
- Next by thread: Re: TECH: WPC Resets - flipper activated
- Index(es):
Relevant Pages
|
