(Topic ID: 247662)

Baywatch Flippers always enabled. Is 7406 the issue?

By svendmute

6 months ago

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  • 6 posts
  • 3 Pinsiders participating
  • Latest reply 5 months ago by PinballManiac40
  • Topic is favorited by 1 Pinsider


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cpu blanking (resized).png
cpu - flipper (resized).png

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#1 6 months ago

So I bought this very fine specimen of a Sega baywatch.
It has this annoying issue with the flippers being enabled even when the game is in attract mode. Everything works fine. Popbumbers, slings, gi relay etc...

I've already replaced the q80 transistor and the 7402 (socketed and buzzez out ok) at U2. So I noticed that the blanking signal comes from the 7406 at 12F.
Pin 3 of 7406 is low meaning the relay is on.
Pin 4 is always high.
My guess is that Pin 3 should also be high when in attract mode, since shorting pin 3 and 4 disables the relay. I can hear it click.
So my question is:
Can I assume that the 7406 is bad or is it something more up stream I should look at?

Any help or advice is really appreciated!!!

cpu - flipper (resized).pngcpu blanking (resized).png
#3 6 months ago

Thanks for answering. I changed to 7406 and still no change. BUT I might have found another issue. It could be a broken trace from 12B pin 11 and 12 going to 12e pin 2. Ill keep you posted.

1 week later
#4 5 months ago

Little update: I have been a bit confused by the schematics. On the cpu logic board diagram page 1 of 4 one of the 7406s is labeled to be at 12E but the correct label should’ve been 11F. I replaced both but no change. But I will look at the connections to pia chip at 11D and hopefully I will be wiser. Or should Inlook at the timer chip?

1 week later
#5 5 months ago

So I managed to fix the issue! It turns out that the blanking pins on 12B is 3,6 NOT 9, and 11, 12.
On the schematics its really looks like pin 9 on 12B is also soldered to blanking, but very not logicically as its actually pin 9 on 12A.
Somebody had worked on my board before and made this mistake also.

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