Have a Gottlieb Roller Disco Wide Body. System 1 with new driver board and power supply by RottenDog. CPU replaced with Pascal PI-1. Worked fine until we moved it 20 miles to its new home. Now if machine is nudged, random scoring of 10 points up to couple of hundred points (in 10 pt increments) will occur. Sometimes you get a chime (electronic sound generator replaced with re-built chime unit), sometimes you don't.
Have visually checked all switches and tested them while machine on, nothing seemed out of the ordinary.
I am a novice. The guy I bought the machine from has been more than helpful! He rebuilt the pin, and has spend hours trying to figure out what the issue is. At one point, he cut a wire to a switch, and that stopped the random scoring, but also stopped some normal scoring (and chimes).
So he reconnected it, and problem returned. Any suggestions on how to find the offending switch or what else might be the problem?

Pics below, one a close up of talked about wire (blue terminal), second a pic of entire board with close up pic area circled.

Also, pop bumpers function but don't sound chimes or score points. I have read they should score 100 points per 'pop'....

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forgot to mention, when I ran a test/diagnostic of c-10 c-100 and c-1000, the c-10 did not chime, the other two did.

Thanks, once I get the random scoring fixed, I'll look at that. May end up keeping the chimes, at least for now, because my 2yo granddaughter loves the game, and walks around saying "ding ding ding ding", imitating the chimes.....brings a smile to my face everytime I hear it!

Thanks for that! I followed your suggestion, and have good news and bad news. Good news, found one diode that was bad (no reading), and replaced it. Bad news, game still scores randomly, and its a lot of scoring, more than before, 50 to 80 points at a time in 10 pt increments, some times I get the 10 pt chime with the random scoring. All I have to do is hit the flipper button(s), and the random scoring begins. Also, see picture, the two areas highlighted I thought were 10 point scores do not score at all. Any other suggestions very welcomed!!

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Will do..

and
maybe this is nothing, but diodes tested all measured around 0.2 on MM except for bad one (0). Replacement diode read 0.5 vs 0.2, could this have anything to do with increased sensitivity of random scoring?

pics of all components on back wall

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3 wires to chime box disconnected, points still score, random points still tally.

ALL contacts that I could find separated with folded paper, random points still tally

by the way, noticed when chimes did sound with random point tally, the lower chime would ding once (10 pts?), then if field bumped or flipper activated, higher pitched chime would ding once (100 pts??)...but random points added seemed like only 50 to 80 points, 10 at a time...

??????

in test mode, the only unusual result I got was no sound when testing C-10 (10 point chime), see post #4 above. will double check pop scoring switches

disconnected the diode I replaced.....no difference in problem, still have random scoring. Assuming first step is to replace diode with proper replacement, then go from there.....

found new first connector you mentioned on ebay, will get if proper diode does not fix problem

ordered and received DMM and diodes (for coils, part number 1N4004). Just tested a new diode on its own, and its reading 0.59, was looking for 0.2. Dang it, guess I ordered the wrong diodes!!
can anyone tell me, for Gottlieb System 1, maybe I should have ordered the 1N270 diodes for switches or the 1N914?

perfect,thanks!

so these 1N270 diodes are harder to find than the 1N4004.... found some say 1N270 Germanium Diodes 40mA 100V DO-7 IN270 1N-270 Glass Axial Diodes for TV FM AM Radio Detection
2 concerns- says 40mA, but my current ones reading 0.2, problem? and these say used for TV FM AM radio detection...so can it be used for my purposes? Sorry for the probably stupid questions, I have little knowledge on these things, thanks!

I have limited paperwork/documentation on Roller Disco, does anyone have documentation that shows all the switches and their point values?

after reading pinrepair.com/sys1, specifically "use 1N270 diodes for switches (1N914 or 1N4148 can also be used, or in a pinch 1N4001/1N4004)", I ordered some 1N270 and some 1N914 (just to be safe). Got the 1N914 in today, was excited. But in testing diode with mm, reading came in at 0.61, way above 0.2.

installed a 1N914 diode for broken one anyway, had nothing to lose. No help. In fact, in testing the coils, I get no sound for C-10 AND C-100 now.

Hoping once 1N270's come in next week, problem will go away.

Also did switch test on the flippp board, nothing came up as broken or working improperly.....

update- just received 1N270 Germanium Diodes. Tested one, looking for 0.2v....nope, just like the others i ordered, its reading 0.631........Still, just replaced non working diode with one of these new ones, got nothing to lose, right? Interesting results....machine seems 'better', but still not right.
Before installing latest diode, C-100 chime had stopped working during testing of boards, now I get a chime when testing C-100, sounds weak, but it is working. (Still no C-10 chime during testing). Also, random scoring is not as bad as it was, ie, before, with 'bad diode/no diode', triggering flippers would cause random scoring of 20 to 70 points in 10 point increments. With latest diode 1N270, random scoring still occurs, but it only adds 10 to 30 points at a time.
So, do I order another diode, one specially rated at 0.2v, even if part number does not match with suggested replacement parts? Or do I move on and continue to try and find a bad switch, and is there any way to do that besides hitting the rubber/switch with a ball/finger?

yes, that is how I tested all the diodes. I will test them all again, and will continue to look for switch that is stuck or shorting out.... if not visual, is there any way to test switches using the DMM?

Thanks Mad Dog! took my DMM and did a continuity test on scoring switches, see pic, yellow tags circled in black.

Have about 6 switches were I could not get a tone after multiple attempts. Thing is, I could swear most of them seem to add points when activated.

Also, could it be a central connect point to one of the boards that is the issue??? Probably going to ask a friend to come over next week so we can retest all switches, 4 hands better than two for this work. Mad Dog had recommended replacing a couple of cables and re-pinning, wondering now if this is the issue.

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i figured it was operator error, so tested them again, this time with wife pushing the switch to close them one by one, freeing up my hands to get better connections..
Same results.... could still be me not finding good contact points, but here's a new issue. Lowered playing field, turned pin on and started testing individual switches. the ones that tested 'no tone with DMM test' either scored no points when triggered, OR scored 2 or 3 times the number of points it should have given.
could i have an issue with one of the boards? Or maybe some of the connector pins have corrosion?

Update. The guy who I am hoping will help me solve the problems with my RD is healing up. He had some minor surgery, hopefully will be up to speed in another couple of weeks. Meanwhile, played the pin last night, the problems deepen, and I am wondering if the core issue is board related.

In a nutshell, the problems are 1) sometimes (and this goes for probably more than half the sensors) points are given/sounds are heard, sometimes nothing and sometimes double the points due are given. 2) as the sensors are hit, the scoring slows down and backs up, so after the ball drains, scoring and sound can continue for another 3-8 seconds. 3) Still have issue of points added (10-30 per flip) when flipper buttons are hit. 4) Noticed last night, when point total exceeded level for free game, no knock was heard, no game was added to total left on backglass. Yet, after game, got a match on score and knock was heard, one game was added.

Frustrating to say the least. Any thoughts or suggestions welcomed. Would love to fix this on my own, am fairly competent fixing most things that 'break', but my experience with pins is limited at this point.

Hi, another update. Long story short, replaced Rottendog driver board with new Rottendog driver board. Game plays faster, scoring is better, BUT, still have 10 point random scoring in bursts of 10-50 points, triggered by flippers being activated or even bumpers/targets being hit, in short, any jarring at all of playfield causes random scoring. So, turned machine off, raised pf and immediately smelled burning. Finally tracked it down to 10 point chime coil being Extremely hot to the touch and smelling 'burnt' (electronic chimes were replaced months ago with chimes, which have worked fine until recently). So, as discussed before, I seem to have a 10 point target that is misfiring for whatever reason. I have tested some of the 10 point targets, they seem fine, but I dont know if I am testing all the 10 point targets.....does anyone have a schematic or diagram that shows all the 10 point sensors on a Roller Disco?????

ok, thank you both for those suggestions. Hopefully guy who has been helping me (and has much more experience) can come over and work on this with me soon...in the meantime, noob question. in the photo, just noticed the coil spring was over the end of the post and very close to touching the lever bar the coil is attached to...(I adjusted it away) could that cause the random scoring? This is a 10 point switch...am hesitate to turn machine back on and risk burning out coil or driver board until I have my friend look at itwGuhG01PSQyGLCxL7Hanqw_thumb_50f (resized).jpg

Coil spring not the problem.

I finally did find the stuck switch. There is a 10 point switch behind each bank of drop down targets that spell ROLLER (left hand side) and DISCO (right hand side). The contacts on the switch behind the drop down targets on the LHS were too close together, any bump or vibration would cause the contacts to touch.

The only reason I found it was a lot of searching and a little luck. I had the playfield vertical with the power on, and was tapping on every contact I could find with a wooden spoon. I tapped on the housing for the drop down targets, noticed it was ultra sensitive, and finally saw the offending contact while looking through the housing into the playfield.
Thanks to all of you for the great advice and suggestions!!!!!!

Guess I spoke a little too soon. Yes, random scoring has stopped, all bumpers and targets seem to be scoring correctly, but I noticed the 10 point chime (switched out electronic sounds for old time chimes) was not sounding off, raised playfield, smelled burning, 10 point coil was energized and very hot to the touch. turned game off, disconnected wiring to coil. Reconnected wiring to coil, turned game on, coil immediately energized and stayed on.... so, what could be energizing the 10 point coil even though no points being scored...?

thanks, are you talking the transistor on the driver board?