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I am trying to understand (and fix) a soda machine that doesn't seem to accept 1€ and 2€ coins while all stickers (inside and outside) seem to imply that they should work (5ct to 50ct do work).

I noticed that the coin validator (class "MS 1000" by Mars Electronics International) has a broken pin (see the picture below). According to the PROM's datasheet, that's the A7 pin, but that doesn't tell me anything (I haven't found any documentation on the MS 1000).
I have not yet removed the board from the case because it sits very tight and I don't want to break it, so I don't know whether the pin is connected on the board.

Is that necessarily a problem or is it possible that this is intentional?
Is it advisable to reconnect it?

Picture of the broken pin

Imanuel
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    It pretty much looks intentional, you might want to consult the datasheet what that pin is about, and look where the trace goes that would connect to it – PlasmaHH Nov 08 '17 at 12:34
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    That's the A7 pin. I'm pretty sure the other half of the PROM contains a different set of data, e.g. a factory test routine. – Janka Nov 08 '17 at 12:44
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    TTL inputs [default to high](https://electronics.stackexchange.com/questions/138774/ic-takes-no-input-or-high-as-high-and-low-input-as-low-on-breadboard), so it may still not be a problem regardless. – Ignacio Vazquez-Abrams Nov 08 '17 at 12:56
  • Is the trace that would be connected to that pin connected to anything else? – ratchet freak Nov 08 '17 at 13:08
  • maybe you can enable some sort of secret special debug mode that includes a full version of doom for testing... but probably not – BeB00 Nov 08 '17 at 13:52

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This is only a partial answer - I don't know if it is safe, but I do know that it is not a problem.
The issue with the coins was that there was too little change available and the warning lamp was broken. The soda machine works perfectly with the pin disconnected.

Imanuel
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