(Topic ID: 236783)

High Speed: Random resets + fuses blown


By cjchand

9 months ago



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  • 19 posts
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  • Latest reply 3 months ago by cjchand
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#1 9 months ago

Got a very intermittent (20-200+ games between, average 150+) issue where during gameplay, I hear a beep, the all segments of all displays light up, and if I don’t turn it off quickly enough, it will blow F2. I’ve seen the kickback lock on and believe be heard the knocker kick off when this happens, too.

Checked all coils and their diodes test good. Haven’t gone to the point of replacing the diodes yet given the intermittent nature.

Generally, it happens relatively soon closer to initial power on, but can happen a couple dozen games in. Can play for hours after it happens without issue. Can also play dozens of games from a cold boot and never see the issue.

I’ve verified at TP2 that it has exactly 5.00 volts (even at cold power on) and have reseated the connectors from the power supply. There are several chips that have been socketed as part of repairs, so gave those a good push to ensure they are seated well. Running the CPU checks (SW2) returns a 0 and it goes into attract mode.

Didn’t do this in the past since I powered it off ASAP, but the most recent occurrence I left it running long enough to open the backbox. The CPU board showed a 7 on the LED on the CPU. After replacing the fuse, I played another 50 games without incident. Pinwiki only cites codes 0-5 for the System 11 (prior to 11A) boards, so not sure if that corresponds to U54 failure like with later System 11s.

I haven’t yet pulled the board to reflow connector pins (my initial guess) but wondering if folks have any other ideas. Not that I want issues, but wish this were a bit more consistent so I could get to root cause.

Many thanks in advance!

#2 9 months ago

Forgot to mention that rarely, it will just restart to attract mode without the beep, displays, etc. No reboot needed in this case to prevent fuse s blowing. Happened maybe 3 times in the 700+ games I’ve played on it.

#3 9 months ago

For what it’s worth, just reflowed all connector pins on the CPU board (save the ones that use ribbon cables). Same issue.

Four games in, did the restart, boop, etc, showing “7” on the LCD on the CPU board. Another few games and it just did a reset. No boop, LCD shows “0”. Played fine after that.

Going to try reflowing the power supply board tomorrow AM so I can test it cold.

#4 9 months ago

Continuing my conversation with myself...

Found the large, black Molex was off kilter. Reseated that and squeezed together using some channel locks. Put 3.5+ hours on it the same day with zero issues. Another day, had just one quick reset (back to attract mode mid-ball).

Will pull the power supply board this weekend and reflow that to see if things improve. Still need to verify +/- 12V before I do that, too.

#5 9 months ago
Quoted from cjchand:

Continuing my conversation with myself...
Found the large, black Molex was off kilter. Reseated that and squeezed together using some channel locks. Put 3.5+ hours on it the same day with zero issues. Another day, had just one quick reset (back to attract mode mid-ball).
Will pull the power supply board this weekend and reflow that to see if things improve. Still need to verify +/- 12V before I do that, too.

Is there any evidence of corrosion on the MPU board? Shoot some photos of the board. Also, I would completely rebuild the power supply board with a new cap kit. It may test 5V from cold, but does it dip during play?

#6 9 months ago
Quoted from kermit24:

Is there any evidence of corrosion on the MPU board? Shoot some photos of the board. Also, I would completely rebuild the power supply board with a new cap kit. It may test 5V from cold, but does it dip during play?

Thanks for chiming in!

Board is clean, has the battery holder removed, and has NVRAM board installed. So, should be good on that front. Not a very close up shot, but attached a pic from the most recent fuse-blowing incident.

Not sure what the "7" I've seen on the LCD on the MPU board when it locks coils and blows fuses means, though (see pic). Can't find it at the moment, but came across some iteration of the Pinwiki or Pinrepair content that cited that as a loss of 12V on the MPU. If you have any ideas, would be greatly appreciated.

The caps on the PS board look relatively new, but can't vouch for their age since the work was done before me. Simple maintenance item, though, so will look into that this weekend. Will also check on whether the +5V stays steady under game play.

Thanks!

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#7 9 months ago

I still think this could be the power supply board. What are you getting at the test point for 12v?

#8 9 months ago
Quoted from kermit24:

I still think this could be the power supply board. What are you getting at the test point for 12v?

Getting 13.04V at TP3, -15.31V at TP4. Verified that the ground pin read < 0.1mV both with power off and power on.

Note: Haven’t been able to get it to fail, but presume the -15V at TP4 is out of tolerance range?

#9 9 months ago

Forgot to mention that I measured immediately after power on and after 15 mins of play. Voltages were within 0.05V across 5 readings.

#10 9 months ago
Quoted from cjchand:

Forgot to mention that I measured immediately after power on and after 15 mins of play. Voltages were within 0.05V across 5 readings.

TP4 is fine.

#11 9 months ago

Thanks!

I’ll keep checking the TPs each day and will reflow connector pins on the PS board this weekend.

Again, appreciate the support

#12 9 months ago

No problem.

#13 9 months ago
Quoted from cjchand:

Thanks!
I’ll keep checking the TPs each day and will reflow connector pins on the PS board this weekend.
Again, appreciate the support

Found cracked solder on the pins for the GI connectors (not related to the problem, IMHO) and the connectors that supply power to the MPU (the 4 left pins in the attached pic).

Reflowed all of the connector pins on the board and tested good. Will need to play it from a cold start a few more times before doing any victory dances.

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1 week later
#14 9 months ago

Just to follow up on this, apparently I didn't get whatever is causing the issue. That said, if I let the machine sit idle for 5 or so minutes before playing, there are no issues.

So, just going to live with it in the mean time. Will post back if/when I re-pull the boards and reflow everything.

5 months later
#15 3 months ago

After reflows, have not seen the issue. Will mark this as resolved.

#17 3 months ago

Thank you for the follow up, I too have random resets to audit. Might go for a month then out of the blue it will reset. I'll pull my board and take a closer look.

#18 3 months ago

Good News!

#19 3 months ago
Quoted from Brewchap:

Thank you for the follow up, I too have random resets to audit. Might go for a month then out of the blue it will reset. I'll pull my board and take a closer look.

Just FYI, mine didn’t go to the audits menu. It would beep (for lack of a better sound), every segment on every display lit up, and the game went unresponsive though the lights were lit. Powering off and back on would get it going again.

For what it’s worth, reflowing the power supply pins, though they looked clean visually, seems to be what did the trick. Flowing the MPU pins didn’t seem to affect the outcome.

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