(Topic ID: 234763)

Pinbot alpha displays missing segment


By jmountjoy111

86 days ago



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  • 25 posts
  • 4 Pinsiders participating
  • Latest reply 50 days ago by jmountjoy111
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#1 86 days ago

My recently acquired Pinbot is missing segment p on the alpha numeric displays. I replaced a resistor on the display board that looked rough (even though it measured in the proper range). It has had u13 and u14 socketed in. It looked like one controlled one half of the segments and the other the other half based on the schematics. I switched them, thinking if that chip were bad it would cause another segment to go out. However still only missing segment p. I also measured the resistor in line with that chip and segment p. It measured correctly as well.

This is where my ability to trouble shoot has ended lol. I know the information for the alpha displays comes from the mpu. But I don’t know where. The mpu had some older acid but has been cleaned up and the game is functional. I’m just looking for some fresh ideas on where to go next. I want to get the game 100% functional before I shop it out. I appreciate any help

#2 86 days ago

Is the P segment out on all digits or just one digit of the alpha display?

#3 86 days ago

It’s out on all of the digits

#4 86 days ago
Quoted from jmountjoy111:

It’s out on all of the digits

Lock the displays so the the P segment should be lit. Then test with a logic probe at SRC5 pin 7. You should see a high with low pulses.

#5 85 days ago

I do not have a logic probe but I have one ordered that should be here in a couple of days. I will check that as soon as it gets here. Thanks

#6 81 days ago

Ok so I’ve never used a logic probe. This is what I have so hopefully it will work. Anyone want to chime in and school me on how to use it please

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#7 81 days ago

Hook red lead to 5 volts, black lead to ground. Set switch to TTL. Now you are ready to test.

#8 81 days ago
Quoted from GRUMPY:

Lock the displays so the the P segment should be lit. Then test with a logic probe at SRC5 pin 7. You should see a high with low pulses.

#9 81 days ago

Ok so next dumb question. I go into display test and it just cycles trough the digits. How do I lock them on

#10 81 days ago

press the locking auto up/down button in the middle of the diagnostic switches

#11 81 days ago

Ok thanks. It will only lock one complete alpha digit at a time instead of the whole row but that should work right

#12 81 days ago

Ok so I am assuming that pin is on the left? If so then it lit both high and low and constantly pulsed. Did I do that correctly lol

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#13 81 days ago

Looks like the cpu is ok, now move to the master display board. Repeat test but now check U-17 pins 9 and 10.

#14 81 days ago

I tested pins 9 and 10 on u17 and the result was the same as on src5

#15 81 days ago

With the game off check R-4, should be 8.2k ohms.

#16 81 days ago

R4 reads 7.72k ohm

#17 81 days ago
Quoted from jmountjoy111:

R4 reads 7.72k ohm

Close enough.

Everything is pointing to a bad U-13.

#18 81 days ago

I will order that chip and report back as soon as they come in. I appreciate the help

#19 81 days ago

Here is a procedure to test it.

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#20 81 days ago

Thanks. I will test it first before ordering.

1 week later
#21 68 days ago

I haven’t gotten to testing this yet. I’ve been swamped lately and it’s been cutting into my pin time. I will check it out shortly though.

2 weeks later
#22 50 days ago

I got new chips in. I replaced the u13 since it was socketed in. It instantly blew the fuse for the displays. I replaced the new chip wth the old chip and it blew the fuse again. Also now the game will not boot with ribbon cable attached to the display driver from the mpu.

#23 50 days ago
Quoted from jmountjoy111:

I got new chips in.

Quoted from jmountjoy111:

It instantly blew the fuse for the displays.

Counterfeit chip.

Quoted from jmountjoy111:

Also now the game will not boot with ribbon cable attached to the display driver from the mpu.

5 volt short on the display board now.

#24 50 days ago

Not sure if it's just me, but in your pic it looks like you have a battery damaged CPU board.

#25 50 days ago
Quoted from PiNDoCToR:

Not sure if it's just me, but in your pic it looks like you have a battery damaged CPU board.

There was some older alkaline damage as I mentioned in the first post. It had been previously cleaned and neutralized and the game is functional minus the missing P segment on the display.

I picked up an X-pin display so I’m probably just putting this board up for the time.

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