(Topic ID: 251032)

6803 Truck Stop Display Help

By GLSP3022

2 years ago


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  • 16 posts
  • 2 Pinsiders participating
  • Latest reply 2 years ago by GLSP3022
  • Topic is favorited by 1 Pinsider

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#1 2 years ago

Against my better judgement, I offered to help repair a Bally Truck Stop for a friend. It powered up and displays looked good at his storage unit but it had a missing transistor at Q18.
Drove it 5 min across town, set it up, pulled the MPU and replaced the missing transistor. The game now plays well, however, my displays are now blank with "8" in each of the four sections.
I can faintly see the correct info displayed at random times. But these number "8"s over power everything.
Also if i disconnect the display connector at J2, the 8s are still present.
Voltages on the power supply all test within spec.
Any ideas what happened?? Thanks

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#2 2 years ago

If unplugging J2 connector from the MPU and the '8' still stay on the displays when you turn on power, then there is a data issue on the displays. Please post a picture of the back of both displays.

#3 2 years ago
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#4 2 years ago

Nothing seems out of the ordinary on the back. I'm confused as to why they worked and now they dont. But again this stuff is 30 yrs old now.

#5 2 years ago

Well that is electronics. Some if it is very sensitive, especially if unplugging/plugging in connectors when power is on.

#6 2 years ago

Could this be the 4514 decoder chips malfunctioning on the display board?

#7 2 years ago

Can you try only hooking one display at a time to what those results are?

I definitely would do a diode test on all the transistors before removing any parts.

#8 2 years ago
Quoted from PinballManiac40:

Can you try only hooking one display at a time to what those results are?
I definitely would do a diode test on all the transistors before removing any parts.

I've tried just the left and just the right. No matter which is hooked up, they each display those 8s in the same spots without the other.

#9 2 years ago
Quoted from GLSP3022:

I've tried just the left and just the right. No matter which is hooked up, they each display those 8s in the same spots without the other.

Good. So each display has a digit locked on. I hope you find a at least one shorted transistor on each display board.

#10 2 years ago

Ive poked around a bit looking for shorted transistors. Didnt see any discretely bad ones. I decided to reflow the header pins while they are out. Now I have this.
Dim, but legible text. Just 2 locked on "0"s now.
3rd spot, 2nd player. 6th spot 4th player.

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#11 2 years ago

Ok...so just was pulling on the transistors to make sure they weren't broken....now a perfect left display??? Lol

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#12 2 years ago

Repeated tbe process again on 2nd display. Pulled on all the transistors. Fixed! They must have had legs smashed together.
Ok..easy inexpensive fix.

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#13 2 years ago

So basically sounds like a couple of the transistor leads were shorted to one another.

I sure do like free fixes.

Likely someone or some wires pushed on some of the transistors.

Enjoy!!

#14 2 years ago
Quoted from GLSP3022:

Against my better judgement, I offered to help repair a Bally Truck Stop for a friend.

I would say that it worked out quite well !!! Never hurts to look over anything, even if you never worked on a particular type of game before. Apply knowledge that you learned on other games and see how you can narrow down the problem(s), just as we did above. We did not even need that user manual that you had resting on the game.

#15 2 years ago

The next thing I would do is remove that battery off the MPU board and install 6116 NVRAM. It is an easy plug and play on this board since the old RAM at U4 is already in an IC socket from the factory on these 6803 games. Then the game will be protected for 100+ years and never need a battery replacement ever again.

https://www.pinitech.com/products/6116_nvram.php

#16 2 years ago
Quoted from PinballManiac40:

I would say that it worked out quite well !!! Never hurts to look over anything, even if you never worked on a particular type of game before. Apply knowledge that you learned on other games and see how you can narrow down the problem(s), just as we did above. We did not even need that user manual that you had resting on the game.

I've had a couple 6803 games in the past and they're just a pain to trouble shoot. The 2 phase grounding, the old flipper mechs, the 555 sockets, etc. This TS does have the mushrooms and it's the first screen printed TS cab I've seen. Most have those crappy decals.

But I'll do my best to get it looking and playing well and move on to the next refurb. Thank you kindly for the guidance and I hope this thread helps someone else with wonky displays.

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