(Topic ID: 246936)

F-14 Tomcat - Display is mostly working

By Bigun

4 months ago

Topic Stats

  • 4 posts
  • 2 Pinsiders participating
  • Latest reply 85 days ago by Bigun
  • Topic is favorited by 1 Pinsider


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#1 4 months ago

Working on a machine, customer replaced the speakers with some car speakers he had in his garage. After replacement he smelt burning, and noticed the bottom segments of players 3 & 4 weren't working.

After looking over the display board (D-11610) I couldn't find anything that seemed ruined. I then started testing the components and everything seemed to be ok on the display board - R14 tested within tolerances of a 10K resistor, U15 was putting out anywhere between -19 and -80 volts on each output pin per spec. Wiggled the jumper, nothing seemed to be wrong.

In frustration, I started looking over the board for anything obvious, and I found Q77 looked burnt at one of it's legs. Tracing it back, it looks like it goes back to a solenoid. So it seems unrelated.

Planning on replacing Q77, but I don't know how a set of speakers could lead to all of this, or what my next steps should be beyond replacing Q77. Needing some guidance here.

#2 4 months ago

I'll give the same advice that PinballManiac40 gives ... please post a picture of the board. Please post close up pictures of the battery holder or areas around the battery holder. You can also post a picture of the burned solenoid if you want an opinion on that.

<sarcasm>Please be aware that EVERYONE on Pinside has an opinion so you won't be short on those.</sarcasm>

#3 4 months ago

You guys were right, the Q77 wasn't toasted, it looks like whoever replaced it, didn't clean the board very well when they replaced it. So I cleaned it up.

And before I go into this, the display board is a D-11610, it's not the board schematic listed in the F-14 Tomcat Manual over at Internet Pinball Machine Database - Look up the Space Station machine for the display specific schematic.

After looking at the display board some more, I found a trace that was nearly burned apart, after re-attaching, has fixed nearly 90% of the problem. The top displays (players 1 & 2) are functional again. I didn't mention it but they were illegible and segments weren't even lighting up in entirety. But that has been fixed.

Still having issues with players 3 & 4, but what I've come to realize, it only happens in the first few minutes of operation. Eventually, the lower segments on players 3 & 4 will eventually stay lit consistently. I shot video of the behavior, when it does happen, it seems to only happen when player 3 is lit up, then players 3 & 4 bottom segments go out. Starting to suspect U9 (4050) may be the culprit. Maybe after some use it starts working. I can reflow as a first troubleshooting step, just wondering if I need to go ahead and replace it.

Video of the behavior:

1 month later
#4 85 days ago

Got it fixed. I went ahead and replaced U9 (4050 hex buffer) on a whim thinking it was needing time to warm up and was wearing out. After replacement, it started working perfectly.

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