AC/DC (LE)
Stern, 2012
AC/DC (Premium)
Stern, 2012I have so far been able to fix my older games, but have zero experience on newer games.
Game works for a while
Then the drop target reset starts freaking out and then fuse blows
I keep blowing F8 - 50VDC coils
I got readings on all the test points and this is what I'm getting
5V = 5
12V = 13.1
-12V = -13.8
20V = 23.2
50V = 75.6!!!
I did a quick check on the 50V bridge rectifier in circuit and I think it's testing OK.
Where else should i look?
Thanks
Rob
How does the drop target reset start freaking out. Are some of the drop targets not latching on reset and the coil keeps machine gunning trying to get all the targets latched.?
That’s basically what happens.
I was in the middle of a game. The 5-bank AC/DC drops (it’s always this bank) started shotgunning up and down. Usually I would just shut the game off and that seems to fix everything. But I was having a great game. Was up to 555 million. So I kept playing hoping it would stop.
Eventually the ball ended up in the canon and never came out
F8 blown
Everything is now fine - once I replace the fuse
But I’ve done this loop like 5 times now.
You think it’s the drop targets not catching?
Quoted from dr_spidey:You think it’s the drop targets not catching?
Sounds like it is in the drop bank to me also.
Does the plunger move freely with the machine off, try to eliminate mechanical binding?
There is a post on here somewhere about the latching problem, especially as the targets wear. I made a shim to move the latching deck out a little and it solved the machine gun problem. Mine was never severe enough to blow a fuse though !
In checking the drops I am now remembering that when I got the machine it had issues latching. It had a bad Opto switch. When I swapped that out I thought I fixed it.
It worked for a while but now it’s happening again.
Optos seem fine now though
I’ll play around with the latching and see if that works
But does it matter that my voltage on the board at the 50v is way high at 75 v?
I played a bunch of games. It definitely struggles to reset the drops. Generally taking 2-3 tries to get them to stay. Even the TNT targets. I hadn't noticed as I rarely hit the TNT targets.
So I decided to take both drop targets apart and completely clean them. I figured since they are apart i'll put in new coil sleeves, spring washers, and get a new Rest Ledge. So will be a week beore I can put it back together and see if that fixes the problem
I'm still wondering why I get 75V at the 50v check point on the power board.
Quoted from dr_spidey:I played a bunch of games. It definitely struggles to reset the drops. Generally taking 2-3 tries to get them to stay. Even the TNT targets. I hadn't noticed as I rarely hit the TNT targets.
So I decided to take both drop targets apart and completely clean them. I figured since they are apart i'll put in new coil sleeves, spring washers, and get a new Rest Ledge. So will be a week beore I can put it back together and see if that fixes the problem
I'm still wondering why I get 75V at the 50v check point on the power board.
It's normal. The power is a sinusoidal pattern and RMS is related to the peak voltage of the power signal by the square root of 2 (1.41), so a 50v coil will read in the 75v range factoring that there's also a ~5v buffer built in for power lag.
I seem to remember back in 2012 when I bought my game one of the target banks would machine gun. Then would blow a fuse. Tried cleaning optos but problem returned. Pretty sure my solution was to replace drop target opto board.
This problem is back again
New ledge not helping this time
The A-C-lightning bolt 3 bank (of the 5 bank) is the issue
It appears to not reset all the way. It only seems to be an issue when all three drops are down. If 2 of the 3 down, it makes it all the way up and resets
I went into switch test, and all switches fine
When I just manually try to reset the bank, it definitely has some resistance when the drops are down. If they are up, it moves freely
Any thoughts?
Quoted from dr_spidey:This problem is back again
New ledge not helping this time
The A-C-lightning bolt 3 bank (of the 5 bank) is the issue
It appears to not reset all the way. It only seems to be an issue when all three drops are down. If 2 of the 3 down, it makes it all the way up and resets
I went into switch test, and all switches fine
When I just manually try to reset the bank, it definitely has some resistance when the drops are down. If they are up, it moves freely
Any thoughts?
Refresh my memory, so if 2 of the 3 are down it resets properly, but if any 1 of those 3 is down, it doesn't even try to reset, or it resets unsuccessfully?
Quoted from dr_spidey:No
If any 1 or 2 are down, it resets fine
It’s when all three are down it can’t seem to overcome the resistance.
I put in new coil sleeves
That didn’t seem to help
So if all three are down it machine-guns the bank reset?
Quoted from dr_spidey:Update
Took it apart again. Really cleaned the drop targets and the washers. Seems to be working now.
I guess there was just enough resistance preventing it from resetting
Let's see how long it works
Awesome news. That 5 target bank can be bitchy. I know from experience.
I have a similar problem with the 5 target bank reseting, although it is not a severe problem yet.
I decided to replace the 3 target card and I found this guy on Ebay that sells some boards at a reasonable price to help with this situation. This one is for the 3 target opto card:
ebay.com link: New opto board replaces Stern 520 5252 03 is easy to repair more rugged
He also sells a similar board for the 2 target opto card.
ebay.com link: New dual opto board replaces Stern 520 5252 02 is easy to repair more rugged
I rebuilt my 5 drop target bank to attempt to correct my problem with the lightning bolt target not reseting. What I found on mine was that the optos were working fine. However, the 3 target reset bracket was loose on the plunger because a screw that holds the bracket to the plunger was not tight. See attached photos of said screw. This loose bracket made the lightning bolt target require several bumps from the reset coil in order to reset normally.
IMG_20201107_123222 (resized).jpgIMG_20201107_123243 (resized).jpgI rebuilt my entire 5 target drop target bank. I replaced all the springs on the target bank, including the drop springs and reset compression springs. I replaced all the plastic targets, the plastic ledge and put on new decals and also installed new opto cards and cleaned the entire assembly after I took it all apart. Now, when I fire the cannon at the target bank, sometimes the targets don't get hit hard enough to drop more than one target. It seems that if you hit just one target, it falls normally most of the time. Before replacing all those springs, dropping 2 targets at once was a normal occurrence. I guess after the new targets and springs get used for a while, the targets will fall with less force when hit and operate as they did before the rebuild. The good news is that the entire target bank resets normally every time now and I do mean every time. No more repeated "bumping" on the reset to reset all the targets. So, that problem has been solved on my machine, but it is now a little bit harder to drop the targets than it was before the rebuild.
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