(Topic ID: 226675)

Dr who, strange behaviour ... continued

By jimy_speedt

1 year ago

Topic Stats

  • 11 posts
  • 6 Pinsiders participating
  • Latest reply 1 year ago by Catch86
  • No one calls this topic a favorite


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#1 1 year ago


I have experienced a switch matrix problem. I thought it was that.


But now, it is so strange to me, that I initiate a new thread.

When I switch on the machine, I receive a message "warning, miniplayfield ..." the same kind of stuff that you get when you open the coin door. The history of the problem shows that the whole row 2 seems to be short in test, and it is not due to the boards.

So, I switch on the game, "test report", "Warning minipf" cannot start a game.

After 1 minute, everything goes back to normal. The minipf makes its self test, the "Free play" message is displayed, I can start a game, and everything goes perfect.

I am wondering what it happening !@?&(!

Does someone have an idea ?

Thanks in advance.

#3 1 year ago
Quoted from yellowghost:

Look for row 2 switches touching other objects

Agree. But why is this going back to normal after a while ?

#5 1 year ago

Thanks, I agree, that s why the problem is complex, it is not due to this switch only. There is a malfunction I do not get, related to all switches of row 2, but after a while, looks like everything goes ok. Really strange

#7 1 year ago
Quoted from PinMario:

I had once strange problems on my Who looking like matrix problems. In the end it was old acid dammage on the cpu board, there was green oxidation onder some IC's that was barely vissible until I wanted to replace IC's.

Thanks for the feedback, I ll have a deep look into this. Maybe on the opto board. Actually, this CPU board is new and nothing has changed in the behaviour between the old and the new board.

#9 1 year ago
Quoted from pinwiz_pa:

Disconnect the opto board then turn on and see if it has the same problem. If not you have narrowed it down to the opto board.

Thanks for the idea, indeed the problem does no longer show up. But maybe the optoboard connector is the first switch in the daisy chain, in with case I cannot assume anything, as all the others are disabled at the same time. The physical chaining (almost) never corresponds to the switch matrix row.

If the opto board comes in third place in the chain, I would say, as you do, that the opto board is responsible. Maybe someone knows it, so I do not have to isolate the wire all the way from the backbox to the playfield


#10 1 year ago


The problem was indeed due to the opto board. AS I was not 100% sure of it, I purchased a replacement board and now it is ok. There must be a bad soldering somewhere, but where

thanks you

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