Hey all, working on expanding my education I picked up a Haunted House for my wife and going to try and bring the MPU back from the dead.

Looks like it had a battery failure at one time which someone removed but clearly some damage in the area.

When the machine is powered up you get GI lights, a few controlled lights (player shoots again) are locked on and you have attract sound.. and nothing else.

MPU has good 5 volts and when I checked pin 40 of the 6502 the signal never goes from low to high as it states on piwiki, it just stays at low. This would seem to indicate a failure of the reset section of the MPU.

So where would you start? My thoughts are a good cleaning of the area, upgrade the reset generator circuit per pinwiki and replace anything obviously corroded? Thanks for your input!

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No spare board sadly.

Know anyone who sell battery corrosion repair kit for Gottlieb System 80 series MPU board kits like this in stock?

https://www.greatplainselectronics.com/proddetail.asp?prod=GTLB80-BA-KIT

I sent Great Plains a note, no reply.

I was actually able to get the board to boot once or twice and coin up a game so there is hope for the board. If I have to order everything individually from Mouser I will, rather get as a single bundle though.

1) Did not know! I'd prefer to give someone like Ed my business who is "a little guy" and more hobby centric.

2) Most excited about it coming to life, need to reign in my impatience and thoroughly make a list of items required. Twice I almost ordered a new board but really want to burnish my repair skills.

God bless those doing board repair after a battery goes south, what a chore to pull components off! Like pulling teeth!

Last month did the same on my Star Trek, luckily the MPU was still working but it drooled all down the lamp driver board and I had to replace several of the lamp drivers.

Wut?

1) Picked up Zep tonight, that stuff works great!

2) Pulled the big solder gun out, low watt iron was just not cutting it. Much better!

Have about 10 more pieces to remove, going slow. Parts not here till Thursday. Once the last of the parts are off I'll acid wash again, clean, flux and tin the clean surfaces.

Making good progress!

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Had one or two traces that went missing, easy fixes though. UPS confirms parts will be here today. Have to temper my enthusiasm, might not see any results tonight. Even if I populated the MPU after work I have a power board with a burnt looking diode that needs to be addressed before hitting the power switch. Wonder how much fun I'll have getting the heatsink plate off.

Success!

There is much mischief still to repair but we got a pulse!

Had to free up several plungers as they were bound up or rusted, all the pop bumper boards have to be reflowed, the lower playfield kicker is missing its plunger, the credit and lower playfield displays have something funky going and the lower playfield lighting is all blown out because someone replaced the #313 bulbs with #44 with predictable results. The U relay also had some unhappiness going on but I got that sorted out quick.

WOOT!

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The MPU went together quicker than I thought even ohming out everything periodically. No major problems getting solder to flow onto the cleaned areas. I did have to reroute one or two paths that had pads lifted with good results. Still have to do the toasty looking diode on the power board and have a set of new bridges on general principle.

After work I'll reflow the pop bumper boards, see if I can fix the upkicker with parts from a Data East and convert the 313 lamp circuit to 6V and toss in LED for lower illumination. Not sure what is going on with the displays, have to do some research but will start with a cleaning of connectors.

Lots of progress tonight!

1) Reflowed the popper boards, one is problematic. Holds the popper down for a second or two. Cheap enough I'm just going to replace.

2) One flipper coil bad, will not hold.

3) Upkicker is fixed!

4) Replaced some bulbs and elastics.

5) Some control lamps don't seem to be working, only bonus light that works is the 1x. Have to diag.

6) kicker at #5 had fried coil, replaced. Someone cut wire to "fix"

7) For some reason it always has credits, interesting.

Cleaning connections for two displays made no difference, still wonky output time to time. All segments work. Have to research further. Machine ran all night stable with no issues, several games were played.

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Just an update on this- All the bad coils have been replaced, one pop bumper board was replaced, one lamp driver was replaced, all 4 bridges replaced, large blue cap and small 100 uf cap on power supply replaced, 4 lamp sockets repaired, full LED install aside from backglass and lower playfield 313's, new drop targets on order, IC at location Z23 replaced which fixed the display issue.

The only issues left are finding a proper 6800 orange cap for the power supply (I'm open to suggestions) and the minor problem with the machine always starting with 8 credits. Rather odd problem to have! I don't see any jumpers on diodes and have no clue on that one.

1) Thank you, the machine is in remarkable condition. Playfields are not all blown out either, look to have factory mylar.

2) No ill effects running the larger cap? Not my area of expertise, some warnings out there about straying to far from the factory sizing but that might more of a theoretical problem vs real world.

3) Yes always eight. Slept on it last night and it occurs to me this might be a "self own" as I have not replaced the battery yet. Perhaps the board is simply adding credits since high score to date has not been set. I'll test this today by adding a remote battery pack and see if the problem goes away.

Been enjoyable bringing this one back, lots to sort out but measurable progress.

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Follow up on this, interesting problem!

Installed the battery, which seems to make not a wit of difference.

1) Credits are always 8 when starting the machine or when a game ends. Even if you play a 4 player game as soon as the last player drains the credit display jumps to 8 again.

2) High score is always 888,888. Even if you manually run the score up over that (which gives you the knocker) when the game is over 888,888 will be displayed as the high score too date.

Edit; you sir are da'man!

Now that I have the displays fully repaired I was able to go through diagnostics and sure enough ram test fails "5101"

This MPU is giving me a workout. I'll pop over to your site and place an order this afternoon. Need a cap and a few other odds and ends.

No worries, I'll catch you on the next project Ed. Would not mind a bit hearing about filtering and ripple current when you have free time.

Decided after doing some research to just replace the A2 powerboard and keep the original as a spare and practice on it. Prudent to replace several components when apart which I have not done yet and $70 is money well spent for a new board. Rather than do normal 5101 ram ordered up NVRAM from Weebly and the appropriate NVRAM for my Secret Service too. Cap on the way from Digi-key and 200 LED's on the way from Comet.

Hope I don't jinx myself stating the end is in sight! By next weekend should be a fairly robust machine with rebuilt power supply, ground mods done, no batteries and full LED's.

1) Pair of new chips came in for location Z23, both tested fine and one was installed.

2) Replace the four drop targets, upper playfield.

3) Cleaned upper playfield, cleaned posts, installed elastics, soldered the sockets to keep from flickering.

4) Polished the ramp and steel around front of upper level.

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Starting to take a shine to this pin, first widebody I can say that.

Home fighting a cold still so picking at it.. replaced the rest of the elastics today and polished the plastics, ran a ground wire to the buss bar and connected the MPU, driver and chaser boards, replaced the 10 gaskets under the playfield window and adjusted height, tweaked some switches, knocked the dings out of the coin door and adjusted so it opens and closes proper, got rid of the burnt out bulbs behind the coin lens and swapped in LED's.

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Still plugging along..

I'm going to replace the missing "Hidden Passage" plastic with one cut out of steel and print out an overlay covered in Mylar.

Crack that.

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Power board from Gulf Pinball is here so installed it, another package was from Andrew with NVRAM for Haunted House and Secret Service.

Install went well on SS, and the socket install went smooth on HH but still have the ram error which is what I was afraid of. Hazards of starting off with a dead board. Voltage at the socket is 4.48 volts so that should be good. Not sure where to go next! May get out the logic probe and check one of my other System 80 pins to see what activity I should be seeing and compare.
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Pin 18 on the ram socket is suppose to see a pulsing signal from the 74C04/4069 IC located at Z36. I compared Haunted House to my Gold Wings and it clearly shows activity with the logic probe which is absent on Haunted House. So is the chip at Z36 bad (which is just at the edge of the battery damage) or is something causing it to lock high on Pin 18?
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Running things down with the logic probe, I see activity at pin 9 from the CPU but no activity at pin 8 where it comes out and heads off to the ram.

Would it be a safe assumption that the 4096 IC at location Z36 has gone south?

Doing a board search for 4096 chip testing and this post comes up.

https://pinside.com/pinball/forum/topic/gottlieb-system-80-mpu-problem#post-3873319

"Well everyone! I fixed the problem! After studying the schematic for awhile and reading over the 5101 specs. Pin 17 is the chip enable for low power mode and pin 19 is the chip enable pin. I decided to swap out z36 (4069) which feeds pin 19 on the 5101. Bingo! I now have no free credits and high score isn't showing "888888"."

That is the exact problem I was chasing down, 8 credits and a high score of 888,888

Thanks! Board has been socketed for Z36, nothing to do now but twiddle my thumbs and wait for the chips to show up tomorrow along with the last cap to replace big orange. Comet LEDs arrived today and the backbox is done. Only thing not done are the 313 for the lower playfield and the 2 posts on the top left entrance. LED don't fit well so just going to run with 44's there.

I use to feel the same but the bulbs sold now are so terrible quality wise the failure rate is pretty high. I can put in a quality set of LED and not worry about it.

I'll be more than happy to answer what I can! This is my 5th System 80/B system and most heavy repair yet, I'm starting to learn my way around a little bit. Next adventure is a Spiderman board that has worse damage than this I'm going to pick at over the winter. I'm already contimplating a bench setup for them and a scope purchase.

Ugh. The dreaded "Your package is in the system somewhere but trust us it isn't lost" message. The cap is somewhere in limbo (Thanks Post Office!) but looks like UPS will be here today with the 4096 chips.

So close to being completed I can almost taste it.

Victory is mine at last.

It wasn't as simple as just tossing the 4069 chip in but it is now working as intended.

And the cap is still missing.

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