Hi,
I have a Chicago Coin Top Ten pinball machine. In the center of the playfield there is a spinner that racks up points when spun. The spinner scores accurately for the first hour or so of play. After about 70 minutes the spinner fails to register any score. Once the machine is turned off for an hour and then back on, the spinner works correctly for another hour.
In the circuit there are two electric eye relays, one 10/50 capacitor and two 4004 diodes. Is it possible for the capacitor or a diode to go bad when warm and then function properly after cooling off?
Thanks for any input!

Those are the specs/values called for in the parts list. I've had the machine about 15 years and it has done this from the start. It's not a big deal but I would like the machine to function properly. I'm retired now and have time to work on it.

Thanks curriedog, I will do that!

I replaced the capacitor and two diodes. It did not make an improvement.
If I have a fan blow on the photocell I get an extra hour or two of play before the spinner stops scoring. I guess my next step is to rig up a new photocell per PinballlAir's suggestion. Is there a certain type/rating of cad cell I should use? I see some have different wattages.
Thanks

PinBallAir:
Here are pics of photo cell, photo cell circuit & rectifier circuit.

photo cell (resized).jpg

photo cell circuit (resized).jpg

rectifier circuit (resized).jpg

Both diodes are there.
I hurriedly replaced the capacitor and diodes per someone else's suggestion.

IMG_0657 (resized).jpg

It stops scoring after 2 hours of play....I turn the machine off when it's not being played.
Everything else about the game functions properly most of the time. I do get a player or ball skipped once in awhile and those occur more often the longer the game is on.
If it will help, I can try leaving the game on tomorrow for 2 hours or so without play and see if the problem occurs.

If it matters, the game is set up for free play. I do not know what was altered to accomplish that.

Thanks for the suggestions and all the time you've put in...it's greatly appreciated.
I'll run those tests and get back to you tomorrow.

I turned the machine on but did not play any games. I checked the spinner function every 30 minutes. After 2-1/2 hours the spinner stopped scoring. I checked voltages across the photo cell terminals: 19 when lit and 46 when the lamp is blocked.
I by-passed the cell with a jumper and the relays scored.
I then removed the red wire from the cell and checked voltages between the cell and red wire: 46 when lit and 0.5 when the lamp is blocked.
The relays buzz when the cell is lit. They stop buzzing when the light is blocked. They also stop buzzing if I remove a wire from the cell.

I don't understand where the 45-46 voltage is coming from. I checked the voltages with the digital and also analog multimeters and get the same reading. The rectifier circuit, the action kicker and the center pop bumper all read 30 volts (those were the easiest for me to access).

In Top Ten the spinner can stop in either the dark or lit position.
I'm in a rural area. The closest HVAC shop is 3 hours away. I do have a Home Depot 1/2 hour away. They don't stock the cad cell but can have it in about a week. Ebay has a few different ones for $8.50 with delivery in 5-7 days. I think I'll go that route.
Thanks for your help. I'll let you know how it turns out.

I received the cad cell and made the optical sensor per PinballAir's pictures. The cad cell exposed to the light was too sensitive. I cut 8 different block out masks with different size apertures to limit the light. An aperture 13/64" diameter gave the best results. The spinner did score points on slow revolutions but at faster revolutions the cad cell was not able to cycle quick enough and the spinner didn't score. For the time being I have installed the old photocell and will use that until I come up with a better alternative.
Now I have a couple more issues with the Top Ten that I have to work on....randomly skipping a player is the main one.
Thanks for all the help.

Hi all,
I have all the issues with my Top Ten taken care of except for the spinner not scoring points when the game warms up. I have replaced the 2- 4004 diodes, the 10MFD and 1 MFD capacitors, the photo cell and the 2-relays.
The spinner scores correctly for the first hour during play then it stops scoring. If I just start the game (and do not play) after a 1-2 hour wait the spinner will not score. If I turn the game off and wait 20-30 minutes, I can get another 30-40 minutes of play time with the spinner working when I turn the game back on.
When the spinner stops scoring, the relays vibrate but do not energize/de-energize completely.
I have taken voltage readings on the components (in circuit) when the spinner is working and when it is not. The readings are identical. Here are the readings (DC voltage) of each component with the photo cell covered/uncovered.
Photo cell 46/16
Left diode 0/-16
Right diode .1/.7
10MFD capacitor 0/45
1 MFD capacitor 47/30
Rectifier 46/16

As far as I can tell, the rectifier is the only component in this circuit that I have not replaced. Could this go bad if it warms up? Is there another component in the circuit that I'm missing?
The majority of the circuit is near A-26 on the schematic. The spinner relay is also at B-9 and B-14.

I appreciate any assistance in helping me rectify this on-going issue.
Thank you!

Chicago_Coin_1975_Top_Ten_Schematic_Diagram_Continuous.pdf

bottom of board (resized).jpg

top of board (resized).jpg

I replaced the rectifier and after hours of play the spinner is still performing correctly.