Coin In Error 21 Optics problem

[Slotster]

My machine was working great 2 years ago... then I started a basement remodel project. Just completed last weekend and moved the slot into it's new home. I half expected it to have a battery issue, but to my surprise, it's complaining about a Coin-In Optics (Error 21) issue. Here's what I can tell you:
It's a 9" flat-top 3-coin Double Diamond Deluxe.
I disassembled and cleaned the optics - assuming that was my real issue since the machine had been unused for so long. No luck there though.
The optics tests give me no change in display as I move paper between the optics. I get:
10-1
11-0
12-0

The display does blank and come back after closing the door, so I know the door optics are working.
It's a 10Mhz MPU (Not that that should matter, but the more info the better, right?)

I checked the voltages on J/P50. With it unplugged, I get 9VDC across pins 1, 3, and 4. With it plugged in, pins 1 and 3 give me 9VDC, but pin 4 drops to 1.2V. That's making me suspect a bad transistor (Q1), but I haven't done electronics for 15 years.

Based on all of that, I went ahead and got a replacement optic board on order... but I'm open to other suggestions while I wait. I don't have a local source for replacement parts though, so my ability to swap things out for testing is pretty much zero.

Thanks!

[knagl]

A new set of optics will likely fix you up -- in the mean time since you don't have much to lose, you can try Jim's transistor snip trick discussed here (for the PE+, but they're the same on the S+). 

[Slotster]

Thanks for the suggestion. I gave it a shot, but it didn't help things. I used a de-soldering iron to do so though, so I can at least put that transistor back if it turns out to be something entirely different. In the mean time, I'll just sit back and wait for the new parts to arrive. Incidentally enough, I noticed that the post you linked to had identical symptoms as mine, and taking out that transistor didn't help his situation either. I'll keep my fingers crossed...

[knagl]

Perhaps just a coincidence, but I encountered a coin-in optics issue on one of my machines after a recent move.  Maybe they don't like to be bounced around. 

[proten]

I had a S+ do that to me and I found the
left plug to the mother board
was not seated all the way.

I unplugged and replugged it in the
mother board and fixed the error.

Paul

[Jim]

while your waiting for your part to arrive you could check one more thing.   I just went out to a machine I have, and opened the door, removed the cc-16. hooked the black lead of the meter to any metal part, checked the LED voltage on pin 8  it was 9vdc.  pin 1 was .7vdc, pin3 was 3.85vdc, pin 4 was .7vdc.

Q-4 was removed from this optic board.  I put the probe on pin 3, pushed the white test button on the optic board, the voltage went to 9vdc. put a popcycle through the optics(where the coin would go)  pin 1 would go to 9vdc when the stick would block that optic,  pin 4 would do the same. as did pin 3.

so given your results, I would try and see if you try the test button and see if pin 3 will go to 9vdc, if that works ,then hold the test button in and check out pin 1 (you will have to use the stick to block the optics, if it works  then probably DS-2 may be open or a cold solder joint.

Jim