Re: WPC-replaced all BR's and caps and still shutting down
- From: "GPE" <GPEnospam@xxxxxxx>
- Date: Fri, 30 Nov 2007 22:15:26 -0600
"AL" <AL@xxxxxxxxxxx> wrote in message news:49b8ed4d-9b29-4ec0-9516-0328eb3384ce@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
On Nov 29, 10:20 pm, "deafdumb&blindboy" <ilduc...@xxxxxxxxxxxxx>
wrote:
On Nov 29, 10:14 pm, AL <A...@xxxxxxxxxxx> wrote:
> John,
> An LM323 is a +5V fixed regulator. The Output connection will be 5
> Volts (+/- .25V) greater than the referenece (Ground) connection. If
> the ground connection is suspect and floats, so will the output float
> respectively.
> IIRC the input pin can be anything from +7 to +45V or so. If you
> measure directly across the output and ground connection (not cabinet
> ground) and it does not read a 5 volt difference, and the input
> voltage is within range, then it should be replaced.
> AL CARGPB 33(1/3)www.Team-EM.com
Al-
I measured the voltage at the TP2 and the TP GND, both on the board -
I just put alligator clips onto them so I could focus on what the game
was doing. I don't get what you mean about a 5 volt difference,
though, I'm just shooting for 5 volts period. Why should I be
concerned about the input voltage, when it's the output that matters?
J.
A few things will cause a fixed voltage regulator output to rise:
~ The "Ground" pin is not 0 VDC. The output of an LM323 will be 5
Volts above the ground pin. If the ground pin is 3 Volts (poor
connection or not connected to the machine's ground), then the output
pin will be 5 volts above that, or in this case +8 Volts.
This is where the WPC machines screwed up in the design.
The Bally's designed the regulator to go very slightly higher than 5V as set by R50.
The WPC machines don't have this resistor in the ground path so you cannot adjust the voltage up incase you have an LM323K that rides a hair on the low side...
-- Ed
~ Input Voltage exceeds the maximum voltage rating for that device.
(IIRC, that's about 40 Volts above the output). If that voltage
climbs, the output will climb. This is a short term condition before
complete failure.
~ Other circuits on the output of the supply feeding back onto the 5
Volt bus. Other, higher voltages are on that board and may be feeding
through a defective component.
~ Last and very, very possible, bad Voltage Regulator.
AL CARGPB 33(1/3)
www.Team EM.com
.
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