Baywatch DMD Resetting Issues

(Topic ID: 237862)

Baywatch DMD Resetting Issues


By grantopia

13 days ago



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  • 29 posts
  • 4 Pinsiders participating
  • Latest reply 5 days ago by grantopia
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#1 13 days ago

I'm having an issue where the DMD on my Baywatch will periodically reset briefly and the game continues as normal. It seems to happen typically at the beginning of a ball right after its served to the shooter (but not in multiball when balls are served), or after a video mode, or at least that's where I notice it most.

I've done most of the following from this thread (https://pinside.com/pinball/forum/topic/guide-to-dealing-with-large-dmd-games-with-resetting-displays#post-2623239):

Replaced C11-14 4,700 uF caps on the power supply;
Replaced CN5 connector and header on the power supply; and
Replaced connector and header on DMD display board.

I'm getting about 4.93v at the power supply and 4.85 at the mpu, but the game itself isn't resetting. I'm thinking my 5v is still a bit low but at a bit of a loss on what to do next. I haven't replaced the fuse clips, but they don't seem weak and look fine, although I guess they are cheap enough to where I could just shotgun them. The bridge rectifier also gets very hot, which I assume is normal (?), but I guess I could replace that as well.

On the schematic it looks like the C7 cap is in the 5v circuit on the power supply, so I'm wondering if that's worth a shot too?

Open to thoughts - thanks!

#2 12 days ago

TGIF morning bump! Anyone run into this?

#3 8 days ago

Alright hoping someone can chime in here...recapped the whole power supply, changed the fuse clips, and did the modification listed in service bulletin 106 (http://arcarc.xmission.com/Pinball/Stern%20Service%20Bulletins/bulletins.htm) and STILL getting the same voltages and dmd resets periodically at the beginning of each ball. Anyone have this issue or other ideas? Help!

#4 8 days ago

I would change the voltage regulator on the power supply. Are you testing the 5v power at the power supply's dedicated test point?

#5 8 days ago
Quoted from Crash:

I would change the voltage regulator on the power supply. Are you testing the 5v power at the power supply's dedicated test point?

Those readings were at the test points on the power supply and the mpu. Are you talking about the bridge rectifier or is there something else? I'm at a loss as to why this only happens at the start of a ball or sometimes after video mode. Maybe those parts of the game draw down the voltage enough?

#6 8 days ago
Quoted from grantopia:

Those readings were at the test points on the power supply and the mpu. Are you talking about the bridge rectifier or is there something else? I'm at a loss as to why this only happens at the start of a ball or sometimes after video mode. Maybe those parts of the game draw down the voltage enough?

measure the voltage at the pins going into the dmd controller. Lift the connector up slightly to measure the voltage. The dmd draws alot of power so it might be low or near low specifically at the dmd connector. my dmd was resetting just like yours at 4.91vdc.

#7 8 days ago
Quoted from grantopia:

Are you talking about the bridge rectifier or is there something else?

There is a voltage regulator on the large heatsink. Not commonly the problem, but I have replaced these before and saw an improvement on Williams WPC power driver boards.

Quoted from Langless28:

my dmd was resetting just like yours at 4.91vdc.

What did you do to resolve this? I’m only getting 4.95v at the connector and getting right at 5v at the power supply. I did the CN6 mod from the service bulletin and ruled out the header and connector on the display board. It seems to be stable now but would love to get 5v or really close at the display board.

#8 8 days ago
Quoted from Langless28:

measure the voltage at the pins going into the dmd controller. Lift the connector up slightly to measure the voltage. The dmd draws alot of power so it might be low or near low specifically at the dmd connector. my dmd was resetting just like yours at 4.91vdc.

That's a good thought, I'll see what it is and report back if it helps. I'm still at a bit of a loss why it only happens during certain instances (ball served to shooter, but only at a new ball, and the end of a video mode).

Quoted from Crash:

There is a voltage regulator on the large heatsink. Not commonly the problem, but I have replaced these before and saw an improvement on Williams WPC power driver boards.

What did you do to resolve this? I’m only getting 4.95v at the connector and getting right at 5v at the power supply. I did the CN6 mod from the service bulletin and ruled out the header and connector on the display board. It seems to be stable now but would love to get 5v or really close at the display board.

I'll check that and the bridge rectifier too. How did you end up resolving your issue?

#9 8 days ago

I guess mine is resolved, but we will see. It survived multiball and supposedly is fixed, but I’m not at the location all the time.

I simply moved the thick custom harness I made from connector CN5 to CN6. Since the thicker wire did not securely punch down to CN6 I had to solder them on to the connector pins (not the header on the power supply).

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#10 8 days ago
Quoted from Crash:

I guess mine is resolved, but we will see. It survived multiball and supposedly is fixed, but I’m not at the location all the time.
I simply moved the thick custom harness I made from connector CN5 to CN6. Since the thicker wire did not securely punch down to CN6 I had to solder them on to the connector pins (not the header on the power supply).

I ended up repinning CN6 with a molex connector since I was in there anyway. It's possible the header pins on that need reflowed or replaced I guess. Worth checking next time I have it out of the game.

Just realized that my post quoted weird. I was asking how Langless28 resolved his issue (not that I'm not interested in yours ).

#11 7 days ago
Quoted from Langless28:

measure the voltage at the pins going into the dmd controller. Lift the connector up slightly to measure the voltage. The dmd draws a lot of power so it might be low or near low specifically at the dmd connector. my dmd was resetting just like yours at 4.91vdc.

Also curious how you fixed your game. What is the voltage directly at the display board after the fix?

#12 7 days ago
Quoted from Crash:

Also curious how you fixed your game. What is the voltage directly at the display board after the fix?

I had that bulletin cable lying in a box for a while. Used that and put a new header on dmd board. Only went up to 4.96 -ish volts but that was enough to not cause it to reset anymore.

#13 7 days ago
Quoted from Langless28:

I had that bulletin cable lying in a box for a while. Used that and put a new header on dmd board. Only went up to 4.96 -ish volts but that was enough to not cause it to reset anymore.

I've got 4.88 at the dmd connector. It did reset while I was measuring and I didnt see any additional drop when it happened, although it may be too fast. My guess is this just a bit too low for it?

A buddy has an aftermarket power supply we are going to throw in and see if it makes a difference.

#14 7 days ago
Quoted from grantopia:

I've got 4.88 at the dmd connector. It did reset while I was measuring and I didnt see any additional drop when it happened, although it may be too fast. My guess is this just a bit too low for it?
A buddy has an aftermarket power supply we are going to throw in and see if it makes a difference.

I would bet 4.88 is too low. If you did all the recapping, reflowing, new connectors, fuse, what’s next?

#15 7 days ago

You know, I recall once temporarily using an external 5v power supply for this DMD board on a Frankenstein and I think that solved the problem. Louis from PinballSP has seen this issue many times while testing his new displays and DMD boards. He theorizes as these boards age, they become more power demanding and the tolerances on the game's 5v supply are no longer able to maintain the 4.95v minimum voltage. But there is no concrete evidence to back that claim up.

#16 7 days ago
Quoted from Langless28:

I would bet 4.88 is too low. If you did all the recapping, reflowing, new connectors, fuse, what’s next?

That's what I'm asking myself ha. Aside from the bridge rectifier and the large transistor there isn't much I haven't touched on the power supply. My buddy has an aftermarket one (I forget which brand off hand) I am going to borrow tomorrow and see if it makes a difference. Maybe I can at least isolate the issue that way.

The game still plays fine but its annoying me to the point where I am determined to win against machine.

#17 7 days ago
Quoted from Crash:

You know, I recall once temporarily using an external 5v power supply for this DMD board on a Frankenstein and I think that solved the problem. Louis from PinballSP has seen this issue many times while testing his new displays and DMD boards. He theorizes as these boards age, they become more power demanding and the tolerances on the game's 5v supply are no longer able to maintain the 4.95v minimum voltage. But there is no concrete evidence to back that claim up.

How would that work exactly? Never heard of it. My buddy I mentioned above said something similar to me, he put it "those boards are trash just replace it already" so you may not be far off in that they may just "age out" after a while as he has experienced the same thing anecdotally too.

#18 7 days ago

You can just buy a 5v 2A or higher power brick that plugs in to the service outlet and wire that to a molex connector for the display driver board.

#19 7 days ago

Was the bridge rectifier (DB1) tested? My Baywatch and Maverick both had DMD resets during gameplay (both have the service bulletin cable). Game continues to play, CPU info would be displayed during the reset before showing the scores again and sometimes the music would be silent and only the sound effects played until the next ball or a mode triggered music again.

In each case, DB1 was the culprit.

#20 7 days ago
Quoted from PoMC:

Was the bridge rectifier (DB1) tested? My Baywatch and Maverick both had DMD resets during gameplay (both have the service bulletin cable). Game continues to play, CPU info would be displayed during the reset before showing the scores again and sometimes the music would be silent and only the sound effects played until the next ball or a mode triggered music again.
In each case, DB1 was the culprit.

I bought some bridge rectifiers but since the cable fixed my issue, I am not sure I want to replace it. Is it true that it has quick disconnect leads soldered to the board? Per the p/n the bridge has quick disconnect tabs and not thru-hole leads.

#21 7 days ago
Quoted from Langless28:

I bought some bridge rectifiers but since the cable fixed my issue, I am not sure I want to replace it. Is it true that it has quick disconnect leads soldered to the board? Per the p/n the bridge has quick disconnect tabs and not thru-hole leads.

Oh, if the cable fixed the issue, then don't do anything else. The BR does have large tab lugs and it's a fairly simple replacement since no other components are nearby to be careful of.

#22 7 days ago
Quoted from PoMC:

Was the bridge rectifier (DB1) tested? My Baywatch and Maverick both had DMD resets during gameplay (both have the service bulletin cable). Game continues to play, CPU info would be displayed during the reset before showing the scores again and sometimes the music would be silent and only the sound effects played until the next ball or a mode triggered music again.
In each case, DB1 was the culprit.

I need to test it since it's one of the last things I haven't looked at yet. I'll have the PS out anyway so I'll check it and see how it looks.

#23 7 days ago
Quoted from grantopia:

I need to test it since it's one of the last things I haven't looked at yet. I'll have the PS out anyway so I'll check it and see how it looks.

mind taking pictures of the DB1 and that area if you are replacing it.

#24 7 days ago
Quoted from Langless28:

mind taking pictures of the DB1 and that area if you are replacing it.

Sure, I don't have a replacement part yet but I can when I do!

#25 7 days ago

I work from home and am standing 10' away from Baywatch. So here's your pic.

Silver square under the heat sink is the bridge rectifier at DB1.

I've had to replace the BR on a few Sega pins due to DMD resets. I've noticed that when it's bad, it gets noticeably hot to the touch after keeping your finger on it a few seconds. Compared to the BR that's on the board below this, which runs cool, mildy warm to the touch. Certainly take the board out to test the BR, but if it's hot I bet it will test bad.

20190313_101028 (resized).jpg
#26 7 days ago
Quoted from PoMC:

I work from home and am standing 10' away from Baywatch. So here's your pic.
Silver square under the heat sink is the bridge rectifier at DB1.
I've had to replace the BR on a few Sega pins due to DMD resets. I've noticed that when it's bad, it gets noticeably hot to the touch after keeping your finger on it a few seconds. Compared to the BR that's on the board below this, which runs cool, mildy warm to the touch. Certainly take the board out to test the BR, but if it's hot I bet it will test bad.
[quoted image]

Mine gets super hot, which I thought was normal and why some have a heatsink now...I'd test it to be sure either way though. After today I should at least have it narrowed down to the power supply or not.

#27 5 days ago

Well here’s where we’re at:

I borrowed the replacement power supply from a friends game that Marco sells (https://www.marcospecialties.com/pinball-parts/520-5047-03) and threw it in. I’m getting 5.02 at the power supply now and 4.98 at the DMD board. Played for about 20 minutes last night with no resets and will continue to keep an eye on it when I get a change to play a few games today, but feeling much better about the voltage there.

I did test the bridge rectifier and it reads fine so I’m thinking that’s not my issue and that Crash may be right in that these boards just age out over time and need to be replaced since I’ve basically rebuild the whole thing at this point and can’t pull quite enough voltage out of it.

For $99 bucks I think I’m just going to cut my losses and throw a new board in there since it seems to work good. At this point I’m like 40 bucks in parts plus my time into rebuilding it and am content to never have to pull it out of the game again.

While unfortunately this won’t help anyone else get to the bottom of it, the replacement is cheap enough to where it’s probably just a wash anyway unless you have better luck then I did.

#28 5 days ago

I actually meant the display board getting old not the power supply, but I’m not surprised a new supply supply helped. If the display boards are indeed drawing more power over the years than designed, new power supplies would be better equipped to handle the loose tolerances in the amperage draw.

#29 5 days ago
Quoted from Crash:

I actually meant the display board getting old not the power supply, but I’m not surprised a new supply supply helped. If the display boards are indeed drawing more power over the years than designed, new power supplies would be better equipped to handle the loose tolerances in the amperage draw.

There were a few caps on the display board I thought about replacing but I'm just going to ride it out for now and enjoy playing it for once!

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