double post, sorry
Pinball info
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DMD Not Working
- Thread starter RetroRepair
- Start date
Well I thought first thing's first, let's check the fuses on the DMD board.. 8 and 4amp?? These are supposed to be 375ma
So I decided to go through the rest and there's a bunch that were far too high so I'll be putting messing about with this on hold until I get the new fuses in. I'll probably grab a known good DMD controller before then though so I at least know if that's where my issue lies or not when I get the fuses. I'm not spending any more time messing about with that.
Thanks for the advice guys!
I keep telling people. If you buy a second hand pinball machine, (that has not been work-shopped by someone reputable) then it is absolutely 100% certain that the fuse fairy will have visited at some point and dangerously overfused half of the fuses. I am just doing video after video of find like 20amp fuses where there should be a 125ma or similar. I just don't get how people can be so careless to that extreme.
Good luck, but I really think you have power/ground issues across the machine that you need to resolve before doing anything else. You need to have rock solid voltages with just the Power/Driver board plugged in before you are plugging in other boards else you are risking damage
This is what happens when wrong fuses are in machines ,this happened to my volcano that had a wrong fuse nit .......
Yikes! I smelt that one, but never saw it happen lol
How bad was the overfusing?
Yeh it was a big cloud of smoke at pint all party last year,the game had changed hands a few times,it was a fuse I failed to check it was a 10 amp when it should of been a 2 I think
Yup,had countless mega bad ones - like 1/8 amp but they used summat like 8 amp
had tin foil(countless times),cable 1.5mm wrapped around fuse,fuse bypassed alltogether,and one I should have took a photo of.
A 20mm fuse beatifully soldered on top of the blown 1 1/14" fuse.But in this case,at least the amperage was right.
Cant emphasise enough importance of checking ALL fuses on a new game for ya - yes,ya cant play the new "precious" for another 20 mins,but will stop bad damage,or worse fire - later down the line.
Also make up some CB's - good for fault finding
had tin foil(countless times),cable 1.5mm wrapped around fuse,fuse bypassed alltogether,and one I should have took a photo of.
A 20mm fuse beatifully soldered on top of the blown 1 1/14" fuse.But in this case,at least the amperage was right.
Cant emphasise enough importance of checking ALL fuses on a new game for ya - yes,ya cant play the new "precious" for another 20 mins,but will stop bad damage,or worse fire - later down the line.
Also make up some CB's - good for fault finding
Ok so I thought I'd finally get round to having another go at this now I have the correct fuses.
So first of all, the beacon. It has a small controller board with a triac and an opto coupler on it. Nothing too complicated, the board takes power from the power driver and on/off signal from the CPU board.
If I disconnected the CPU board cable it still ran on it's own so likelyhood was either the triac or the optocoupler had shorted internally and the signal was fine. I ordered both parts, the optocoupler came first so swapped it out and presto! Now only comes on when it's supposed to. Bingo!
The DMD is a different story
I got the probe out again and found the data coming from the input terminal on the DMD itself looked good and went off to two hex inverters who's output looked like crap. I replaced these and now I get a solid data output from them. Great! Still no image though. In fact, no image at all now so I probed the output from the line drivers and sure enough, all pulled low. Damn. Then I noticed one was getting pretty hot. No shorts were found on the board and everything seemed normal. All voltages are there too, so I'm guessing the line drivers (at least that one) are shot. I removed both and swapped them over and sure enough the same one gets quite hot and the other is stone cold. Are they supposed to get hot or what? Would be nice to figure out which is dead if any.
Anyone got any other ideas?
I guess I'm on the look out for a faulty Cherry DMD for parts anyway as I'm convinced this is where my issue lies and you can't get the line drivers online. I'm sure the display itself is ok so I'd like to try and fix it before binning it.
So first of all, the beacon. It has a small controller board with a triac and an opto coupler on it. Nothing too complicated, the board takes power from the power driver and on/off signal from the CPU board.
If I disconnected the CPU board cable it still ran on it's own so likelyhood was either the triac or the optocoupler had shorted internally and the signal was fine. I ordered both parts, the optocoupler came first so swapped it out and presto! Now only comes on when it's supposed to. Bingo!
The DMD is a different story
I got the probe out again and found the data coming from the input terminal on the DMD itself looked good and went off to two hex inverters who's output looked like crap. I replaced these and now I get a solid data output from them. Great! Still no image though. In fact, no image at all now so I probed the output from the line drivers and sure enough, all pulled low. Damn. Then I noticed one was getting pretty hot. No shorts were found on the board and everything seemed normal. All voltages are there too, so I'm guessing the line drivers (at least that one) are shot. I removed both and swapped them over and sure enough the same one gets quite hot and the other is stone cold. Are they supposed to get hot or what? Would be nice to figure out which is dead if any.
Anyone got any other ideas?
I guess I'm on the look out for a faulty Cherry DMD for parts anyway as I'm convinced this is where my issue lies and you can't get the line drivers online. I'm sure the display itself is ok so I'd like to try and fix it before binning it.
Here's a question, should I get a pulse at R182 on the DMD? It's always low while all other signals are dancing.
Ok, well it wasn't the DMD. Stuck a new one in today and still bugger all
Will do some further checking another day but I guess a DMD board is next on my list.
Anyone know if those fake pinscore boards PH is selling are worth a shot? I hear they are flakey but pretty well priced.
Will do some further checking another day but I guess a DMD board is next on my list.
Anyone know if those fake pinscore boards PH is selling are worth a shot? I hear they are flakey but pretty well priced.
