(Topic ID: 341009)

Bally 6803 phase A/B illumination issue at boot

By Izzydorio

9 months ago

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  • 5 posts
  • 3 Pinsiders participating
  • Latest reply 9 months ago by Quench
  • No one calls this topic a favorite


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#1 9 months ago

My Bally Party Animal (6803 based) isn't booting because of a phase A/phase B illumination issue.
The LED blinks 7 times, which according to the manual means there's something wrong with the illumination phase A/B:

>8th Flash

>The MPU chip now monitors PIA port CB1 U8. If transitions from high to low are detected the MPU decides that the Phase B Zero Crossing detector is working. It then causes the LED to flash the 8th time.

>If U12,C15,or D9 fails and the CB1 line is stuck high or low the program will not allow game play until the problem is corrected. It is to be noted that this Zero Crossing input is the Phase B switched illumination supply. If the fuse in that line (F5 on the power module) is blown when the power is turned on, the program will not allow game play until the fault on the Phase B line is corrected.

The test points on the *power* board all show the expected voltages. However, there are seven test points on the *control* board, and I cannot find a description of what can be tested on those test points. The fuses are all good as well.

Any idea how I should tackle this issue?

Attached a photo of the board. The components U12, C15 and D9 are circled red, the test points TP1 till TP7 yellow.
(The board obviously has had battery acid issues but has been stable since 2018.)

IMG_20230808_172129_edit (resized).jpgIMG_20230808_172129_edit (resized).jpg
#2 9 months ago

can you post a pic of the board and the ' 7 test points' you are concerned about?

#3 9 months ago

(edited topic post with image)

#4 9 months ago

I notice you are missing Q9 and a capacitor up top.

well that's frustrating, you are correct, I see the test points but no reference as to what they should be.

ITWM I'd follow the TP's to where they go to ideally help give an idea of what they should be.

It looks like TP1 is maybe 5VDC, TP2 is Ground.

#5 9 months ago

Looking at the schematuics:
TP1 = +5VDC
TP2 = Ground
TP3 = +14VDC to +18VDC
TP4 = 5VDC when game is on, 3.6VDC when game is off. This is power for the battery backed RAM.
TP5 = source point for manually activating coil driver transistors.
TP6 = source point for manually testing the coil pre-driver transistor array.
TP7 = source point for manually activating the feature lamp SCRs.

Note, TP5, TP6 and TP7 are not power voltages that you need to measure, they are reference test points used for manually testing onboard components.

Strangely there are no test points for the lamp phase detectors on the MPU board but the schematics page "Sheet 2 of 7" of the 6803 Control Module shows the circuitry. You probably need a logic probe.

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