I am having an issue with the displays on my HH. All of the displays pulse brighter and dimmer, some more than others, especially players 2 and 4. Players 2 and 4 displays will also slightly flicker every 5 seconds or so. This happens in attract mode and during a game. I can't tell for sure if it occurs in display test because the digits change too rapidly to see the pulsing. I think I did see some flickering.

I have done the ground modifications
I have cleaned and "tightened" the edge connections at the cpu. The connectors have already been replaced.
New power supply board and cable.
Reseated the block connectors going to the displays
Tried just having various single displays plugged and all the others disconnected with no change.

The game plays fine and the displays are otherwise correct.

Is this "normal" behavior for System 80 games or is there something else I should be looking at? I tried taking a video to post but could not capture the problem because of the type of artefact you get when you try to video a tv screen.

Thanks for any help.
Bruce

Thank you very much. I am in the process of getting a Rottendog board into it. I'll see if that helps either problem. Fingers crossed.

The lightening lamp chaser is actually what got me started on this quest. I have had the game more than a year and it has always had the pulsing displays and probably the flickering. One day after the game had been on for a minute the displays started displaying nonsense when the lightening flashers went on. I got that fixed by cleaning all the contacts...again, and adding grounding. But then I started driving myself crazy trying to figure out why it was fluxing and flickering.
I hope the new cpu at least fixes the flickering. Will find out next week.
Thanks

Well the new CPU fixed the on/off flicker of displays that occurs every 5-10 seconds. Thanks, Rottendog!
However, I still have an underlying problem that was present with the original CPU. There is a constant flame like flickering of all the displays, all of the time. Displays never go out even for an instant. Just fluxing brighter and dimmer like a guttering candle.
I have checked all the connections, replaced the possible culprit connectors to the CPU, done the grounding mod, checked the display displays individually by unplugging all but one. Still have the problem.
Any suggestions?
Thanks
Bruce

Nope. The displays show all the digits accuratedly. I checked the slamtilt switch just in case and it does not affect it.
Thanks

I have a new Rottendog Power Supply board and it was doing this with the old one and with the new one.
Are you talking about the connector on the cables themselves or the connector on the board? Which one of the 3 or so on there? I also put in a new cable that connects the power supply board to the CPU.
Thanks

I tried to capture the effect on video and I can't because the rapid flickering and the video artefact. Just did not work.

"I meant the connector on the harness. If you've replaced the connector to the CPU from the power supply, that should've done the trick, but I'd suggest repinning the other connectors, especially your connector from the bridge rectifiers."

Sorry. There about 10 20 connectors in there and none of them seem to connect with wires going to the power supply board. Can you please be much more specific. Pardon my ignorance but I need more information especially trying to dig under the lower playfield in the cabinet.
Please tell me
What is the letter/number annotation of the connector
Where is it? Backbox? Cabinet back or front? Close to what?
Where does it go to and from?
Pictures would really help.

Really. Please pardon my ignorance and frustration. I am just sick of this stupid problem that there seem to very little solution to and I would really appreciate more specific, detailed help
Thanks
Bruce

Thank you very much for the clarification. Trying to attach a pic of my power supply board, new from Rottendog. Also, the cable to the cpu (black) is new. The other 2 connectors are mostly insulation displacement type with only 2 wires with a pin type connection. Are these connectors you are talking about?
Thanks
Bruce
IMG_1194[1].JPG

I replaced the connectors that go to that board. No change. All displays continue to flicker constantly. Are there any other suggestions which might be causing this?
Thanks

Took a video of the displays but not seeing how to post video. Just still pics. The flickering looks a lot like the strobing you get in a video taken of a normal display anyway.
Any suggestions would be appreciated.

I did unplug the light chaser board and it had no effect.

Update:
I checked the AC voltage at the displays.
The 6 digit displays that are supposed to have 5 vac are only at 2.5 vac to heat the filament.
The 4 digit display that is supposed to have 3 vac only has 1.6 vac.
There is 60 vdc and 42vdc respectively, as there should be.
If I am testing it correctly, which I am not sure, I think there is 5 vac coming off the transformer. I have been pouring over the schematics trying to make head or tail of them to tell where the drop off might be occuring but I cannot figure it out. It just says it comes off the transformer, goes to A12 J4 and that is all. Sorry, I am not very savvy at reading schematics or translating them into real life. Any suggestions would be greatly appreciated.

Ok. Thanks. I will recheck the voltage.

Here is a link to Youtube video of what is happening. All displays. Worse on 6 digit.

I checked the 5 and 3 vac properly and at the pins into the displays themselves and they are correct. Sorry was not aware that you don't put the black lead on the ground for this.
60 v and 42 v also ok. Once I figure out which is the offset I will check it also.
Thanks for the pics of the schematics.

Found this technical newsletter online. The higher dc voltage and lower ac voltage all check ok. The offset voltage at the displays is 9 v dc (spec is 8 ) for the 6 digit and 4.9 v dc (spec is 5) for the 4 digit. I assume these are within acceptable limits.

image_(resized).jpg

The HH still has the flickering score displays. The connectors replaced. The voltages all appear to be correct. New power supply board and mpu. Any suggestions?

Yep. Did that a second time just recently. Disconnected all the displays and plugged them in one at a time leaving all the others disconnected. Each one had the same issue.
This isn't normal for Gottlieb games of this era is it?

Thank you. I had thought of that myself last night but it is under LED lights and happens whether the lights are on or not. I just tried taking it off of the surge suppressor with no change. I plugged it into a different circuit in my house and even into a plug from a different circuit panel with no change. The new power supply and cpu boards that I have are from Rottendog and I don't see any adjustments on them. I had the same problem with the original boards. Could this be a transformer problem?

Here are a couple close up videos. Unfortunately can't see detail of the filament. It seems to be the filament flickering slightly. It is most pronounced in the digit on the far right and the digit on the far left of each display

I have not. My thinking was it would be unusual for all 6 displays to show the exact same problem, even when isolated from each other, if it were due to a problem on the display circuit boards. I will check it out further. I think they did mention a way to test the capacitors in that old 1982 tech newsletter. Thanks.

Looks like there are 3 caps on each board.
One 1uF axial cap on the 60v dc line
Two 0.01 uF disk caps next to the chips
Would all 3 likely fail and cause this problem or just the larger one?

Ok. Thanks. I'll order some and see if it works.

I have some caps ordered from GPE and will post back once I get at least one installed probably in another week. If anyone has any other suggestions, I would love to hear them. Thanks

I did rejuvenating the displays but did not make a difference. I have 2 suggestions to work on once I have the capacitors and I'll let you know once I get a chance to try them.