(Topic ID: 134545)

Haunted House displays pulsing and flickering

By pindoc1

7 years ago

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  • 65 posts
  • 15 Pinsiders participating
  • Latest reply 6 years ago by pindoc1
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There are 65 posts in this topic. You are on page 1 of 2.
#1 7 years ago

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.

#2 7 years ago
Quoted from pindoc1:

Players 2 and 4 displays will also slightly flicker every 5 seconds or so.

The flicker is normal if you have a stock MPU. After I installed a ni-wumpf (an after market MPU) my displays were rock-solid. I assume any after market MPU would fix the problem, but I've only tried the ni-wumpf, so can't comment on the others, but have only read good things about all the after market MPUs.

There's a bug, for lack of a better word, in the original MPU that causes the flicker in displays 2 & 4. I've traced the flicker with a logic probe all the way back to display control chip output at U5, and can see the logic probe flicker off at the same time the digit flickers. To my knowledge, there is no known resolution to fix the original MPU. It may be a coding issue, or it could be something else.

Quoted from pindoc1:

All of the displays pulse brighter and dimmer,

I'm not sure about this one--some owners have tried grounding the displays along with the other ground modifications and had varying success. The display grounding had no effect on my game--but I did not notice this problem on my game.

#3 7 years ago

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.

#4 7 years ago
Quoted from pindoc1:

I am in the process of getting a Rottendog board into it.

Let us know how it turns out. I'd be curious if the new MPU will eliminate the flicker on your game too.

#5 7 years ago

Try unplugging the Lightning Lamp Chaser board mounted on the back side of the backbox insert and see if the issue goes away.

#6 7 years ago

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.

2 months later
#7 7 years ago

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?

#8 7 years ago
Quoted from pindoc1:

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

Do the displays always shows 0000000 and cannot start a game?
If so, sounds like it has an open slam tilt switch.

Refer to 4.16

#9 7 years ago

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

#10 7 years ago

Following this, as my BH started doing this. I have all rottendog boards except power supply board.

#11 7 years ago

I had a similar System 80 problem recently that I had not previously seen, and it was due to flaky female connectors on the power supply. Rebuild those and you'll likely be set.

#12 7 years ago
Quoted from bingopodcast:

I had a similar System 80 problem recently that I had not previously seen, and it was due to flaky female connectors on the power supply. Rebuild those and you'll likely be set.

I am thinking that or the capacitors for the 60 volts on the power supply need to be replaced.

#13 7 years ago

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.

#14 7 years ago

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.

#15 7 years ago

Can you post a video?

#16 7 years ago

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

#17 7 years ago

"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

#18 7 years ago

Sorry Bruce, sometimes I think I'm being clear when I am not.

The displays get their power from the power supply. The CPU works some magic as well, but let's rule that out for now.

The power supply is where we want to focus. I do not have a game in front of me to tell you connector numbers/letters, but each of the connectors on the powers supply should be rebuilt. use .156 trifurcon pins and molex connectors, which you can can purchase for pennies at great plains electronics. You will also need a crimping tool if you do not have one. Cut the wires one at a time, strip the end, then crimp the new pins on and slide into the connector housing. Doing it one at a time will prevent you from making a grave error.

I hope that is more clear. Let me know if not.


#19 7 years ago

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?

#20 7 years ago

I would start by repinning plugs at J1 and J3. Especially with J3's Pin 1 looking like a banjo string.

4 months later
#21 7 years ago

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?

#22 7 years ago

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.

#23 7 years ago

Upload to YouTube and post the link.

#24 7 years ago

Looks like someone asked a while back whether you've tried unplugging the light chaser board, but I can't tell from your reply if you tried it. I had a flickering digit issue on my Black Hole. Issue went away when I unplugged the light chaser board, and I was able to fix it by adding a ground wired to the light chaser board. When you did your ground mods, did you add a ground to the light chaser board?

1 week later
#25 7 years ago

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

#26 7 years ago

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.

#27 7 years ago

How are you measuring these voltages? Having the meter black lead to the correct reference point makes a world of difference.

Measure the 6VAC between the "6V AC" and "6V AC RETURN" (not ground). Measure the 3VAC between the "3V AC" and "3V AC RETURN".

And you need an 8V DC offset voltage. Measure this with respect to ground.

I don't have a Haunted House manual handy but there should be a diagram showing how voltage gets from plug at A12 J4 gets to the displays.

#28 7 years ago

Ok. Thanks. I will recheck the voltage.

#29 7 years ago

Is this what you need to see?




#30 7 years ago

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

#31 7 years ago

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.

#32 7 years ago

Your very welcome

#33 7 years ago

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.


#35 7 years ago

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?

#36 7 years ago

My james bond pin does something weird but I never really looked into it to far. Mine will dim then get brighter, yours almost looks like it has a refresh rate problem. have you tried to disconnect 1 display at a time and see if there is 1 display affecting the others?

#37 7 years ago

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?

#38 7 years ago

I know I'm probably wayyyyyy off base with this, but, is your game under fluorescent lighting? I remember reading long ago that the 60hz flicker of household lighting can interact with the refresh rate of the displays to create a sort of "binaural" optical effect. I know Pascal's boards incorporate a feature where you can adjust the display's refresh rate to compensate the flicker for various lighting and line voltage frequency. Just a thought.

#39 7 years ago

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?

#40 7 years ago

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

#41 7 years ago

have you replaced the caps on the displays themselves?

#42 7 years ago

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.

#43 7 years ago

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?

#44 7 years ago

the axial cap will dry out over time, the two disc caps should be fine.

#45 7 years ago

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

#46 7 years ago
Quoted from Drewscruis:

The axial electrolytic cap will dry out over time. The two disc caps should be fine.

Yes, these displays are 35 years old so the electrolytic capacitors probably are going bad.

#47 7 years ago

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

#48 7 years ago

I've got a Haunted House I'm restoring for a friend. It also has the same display pulse/flickering yours does despite the fact I have completely rebuilt the power supply board with all new electrolytic capacitors and connectors. I guess I will have to whip out my CapAnalyzer 88A and test those electrolytic caps on each display board.

#49 7 years ago

Have you tried rejuvenating you displays?

#50 7 years ago

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.

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