Re: Tech: WPC Resets
- From: Stilt <jimsousae@xxxxxxxxx>
- Date: 16 May 2007 17:50:45 -0700
On May 15, 11:01 pm, martin <martin.reyno...@xxxxxxxxx> wrote:
Spent some time chasing down a ToM reset problem. Given that the 5V is
rock solid in the game, I ascribed it to loose chips (of course it
would not fail with a scope on it).
But what I found is that the WPC board has at least a 250mV drop from
right to left. That means that some of the chips are operating below
spec, a recipe for hard-to-find intermittents.
Anybody looked into this voltage drop in any detail? I am thinking
that a single jumper could make a useful difference.
Hi Martin,
Did you check the ground on the CPU board with your scope? I was
trying to track down a reset problem on my TZ with a scope and noticed
both the ground (scope ground connected to the power board) and 5V
line moving when I hit the flippers. I wasn't too suprised to see the
5V line momentarily spike down by a couple hundred mV when I
continuously pounded on the flippers but I was surprised to see the
ground on the CPU board come up by a hundred mV or so. I think the
combination was causing the reset. I suspect a connector problem but
I made a bandaid fix intead of tracking down the bad connector. At the
time I was experimenting with replacing the linear regulator with a
switching power supply board that could be easily adjusted, required
no modification to the power board, no heat sink and fit in the same
space as the linear regulator. So, it was easier to adjust the 5V line
to 5.3V (still within the tolerance of the original linear regulator)
and no more reset problems. The problematic connector will probably
resurface but then it may be easier to find.
Jim
.
- References:
- Tech: WPC Resets
- From: martin
- Tech: WPC Resets
- Prev by Date: Re: EM Tech Question
- Next by Date: Re: KAWEAVER - where are you?
- Previous by thread: Re: WPC Resets
- Next by thread: Wanted: Pinball cabinet in lower Wisconsin
- Index(es):
Relevant Pages
|
