Two Lamps On Instead Of One - RE; CFTBL

[VanillaSlicePie]

 Hello,
Have found 4 lamp columns have this issue when in Single Lamp Test, two lamps illuminate instead of one. Have replaced and tested TIP107/TIP102. Tested ALL diodes. No shorts found. Tested resistors and capacitors. Have replaced ULN2803 at U19 and the 74LS374 at U18. Replaced LM339 at U15/U16. (OK I was going deeper at this stage!!!!) Have I missed something......? 

[Brettski]

A shot in the dark here and I don't know the history of your machine but is there any chance a previous owner has jumped the wires somewhere causing two lights to be activated on the one circuit instead of separately. As you know strange things get done to keep them alive sometimes.

Cheers: Brettski... :)

[DSB]

Are all the diodes the correct bias? Was the machine previously working properly.

Not sure how others would diagnose it but this is what I would do. Disconnect the row plug from the driver board. With a piece of wire somehow only jump the lamp row that the lamp you are testing is on from the plug to the pin on the driver board. If the second light still comes on it must be a short in the field. If not it could be on the board.

[VanillaSlicePie]

Thanks for replies. Firstly all wiring is as per manual. All diodes have been installed correctly. This problem has always been there since day one so just fine tuning! Will try the 'piece of wire from plug to pin trick' and see what happens. Also did some single lamp tests again and found two more columns with the same issue....
Stay tuned. Anymore tips would be most welcomed.

[DSB]

If you determine it is indeed a board fault on the row side.

Just going through the schematic have you considered the U10- U13 row ICs.

Which rows are the problem rows? Is it the same row globe that incorrectly lights no matter which column globe is on test or is it only the associated U10 to U13 IC globes that light as 1 chip handles 2 rows?

I hope that make sense..... U13 for rows 1 and 2 , U12 for rows 3 and 4 and so on.

[VanillaSlicePie]

Made sure all diodes were the same in column 2- no change
Did the wire from connector to pin rows test and the only faults to show up were;
When the"I" in KISS was lit-30million glowed
When the 2nd "S" in KISS was lit-30million glowed,rescue and movie madness all glowed.
So, possibly row  4????? That's assuming you have the column and row sheet for CFTBL.
To throw a spanner in the works, doing the above test in all lamps test didn't show all the issues in single lamp test.
Also have replaced u10 and u11. I looked at schematics and  I do understand what you mentioned.
Appreciate your help.

[VanillaSlicePie]

Row 7 not 4

[DSB]

Are they globes or LEDs?

[DSB]

Seems like you've changed just about every IC to do with the lamp matrix.    At times like these it would be nice to have a spare board to throw into the thing.

Anyway, if I am correct when you single lamp test the "I" in KISS with only the row 2 jumped to the driver board it lights the 30 million in row 7 as well. If this is the case then as you have disconnected the board ground from row 7 it may be picking up a ground from somewhere else. Possibly from row 2. Have you used a multimeter to check for shorts between row 2 and 7 or  row 2 and 4 in the field wiring. Just a theory....


PS: You may already know these useful sites for fault finding. They have help me heaps in the past.
http://pinballrehab.com/1-articles/solid-state-repair/repair-guides/148-lamp-matrix-theory-and-troubleshooting



http://techniek.flipperwinkel.nl/wpc/index2.htm#remove

[VanillaSlicePie]

Thought about putting my IJ driver board in but wasn't 100% sure. Anyway spare of everything would be handy at times!!
I use those web sites regularly. Very helpful so thanks.
Will check for those shorts you mentioned and maybe if that comes up ok possibly look at changing u12/u13???

[ddstoys]

Try doing a factory reset.   I've seen a few instance with controlled lamps that a factory reset solved the problem

[VanillaSlicePie]

Cool! Never done that before so something new to explore.
Thanks. (Bit of poetry there!!!)

[DSB]

A factory reset is worth a try. Corrupted data from the CPU. Also make sure all the chips on the CPU are seated correctly. And the ribbon cable between CPU and driver board.

If it doesn't work you can swap the driver boards as a test only. The lamp matrix circuits will be the same on both. If I am correct the only difference is the flipper relay circuitry on the CFTBL driver board.

I would install the CFTBL board in the Indy though as it has known good field lamp matrix wiring. I would do this way because I think a bad board would rarely affect the field wiring but bad field wiring can defiantly cause problems on a good driver board.

I would leave all the GI, solenoids and any other non essential plugs off too.

[VanillaSlicePie]

No shorts found under playfield

Maybe my lamps are playing up cause after doing a factory reset it seems more lamps are coming on when they shouldn't in the single lamp test!! !@

Driver board swap maybe?

[DSB]

No shorts found under playfield

Maybe my lamps are playing up cause after doing a factory reset it seems more lamps are coming on when they shouldn't in the single lamp test!! !@

Driver board swap maybe?

Unless anyone else has some ideas I would swap the driver board. At least that would clear it from having a fault so you can concentrate on other things with out having that in the back of your head. If the fault is changing then I doubt it is the driver board though.

If you have cleared the field wiring and the driver board could it be the CPU? You could try reseating the chips in the CPU board including the ASIC. I think but you should confirm that the CPUs are also interchangeable as long as the jumpers near the eprom are the same if you change the eprom over.

I would consider leaving your Indy eprom in and installing the indy CPU in the CFTBL and again only plug in the lamp matrix and other essential power plugs. You cant hurt solenoids and things if their not plugged in.