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Maverick switch matrix whacky operation

Johnnyo

Not such a well known member.
10 Years
Joined
Jul 21, 2011
Messages
382
Location
Hertfordshire
Hi all
This is more of a repair log than a plea for help... having picked up a Maverick project machine in December from one of our well known members as p/x for a machine I sold to him.

It come with several known issues broken/loose coil stop under the ramp and some issues with the three opto switches for the multiball entrance and locks also a couple of the drop targets were broken

The coil was simple to repair just required a new bracket, the optos were a different story Sega use ultra bright leds instead of infra red ones as bally/Williams use, I ordered a couple of spares from one of our suppliers but I couldn't make them work very well they were near impossible to line up the sender to the receiver.
The small boards are unobtainable so searching for other answers I came across a tip in using ultra bright orange leds instead of normal red ones luckily I had some left over from a previous project
fitting these made a big difference to the sensitivity and were much easier to set up.
The paddle wheel entrance opto has been an issue with Data East/Sega from day one as it was sited next to a VUK causing vibration's to upset the switch board position. Sega come up with an alternative switch to fit, a magnetic reed switch instead of the opto I managed to locate one in this country well pleased in that.

With all these problems sorted I tried a couple of games and had several switch faults appeared I did not think much of these at this time.
It was apparent that this machine had sat for along time unloved and in the sun as most of the playfield plastics had faded badly and had gone very brittle similar with the rubbers they just fell off, so a new set of plastics were sourced as well all new drop targets,a rubber set came with the machine.

Parts arrived and were duly fitted now play testing began the switch faults were popping up all across the matrix one fault was found with a drop target wire chaffing on a GI socket that cured 4 switch's on one row. During play when operating flippers phantom switch closures were happening
on rows 3-8 from what I could work out but they were all intermittent and they all stemmed from the use of the flippers, mysterious.

Reading up using Marvins guide and Pinwiki ,I tested the cpu board by shorting across the send and receive connectors CN8 - CN10 these all tested ok all rows all columns, so this ruled out the cpu board, so I turned to the flipper board this all appeared ok nothing stood out except it was not the board that the manual stated it should be, but it was factory as the warranty sticker had the same serial number as the rest of the boards. A service bulletin from Sega detailed revisions to the board that should be carried out to upgrade it to the correct revision for this machine this was done and still phantom closures happened.

Now to start on the only other thing the miles of wiring and the switch diodes (to be continued)
 
Hi all
This is more of a repair log than a plea for help... having picked up a Maverick project machine in December from one of our well known members as p/x for a machine I sold to him.

It come with several known issues broken/loose coil stop under the ramp and some issues with the three opto switches for the multiball entrance and locks also a couple of the drop targets were broken

The coil was simple to repair just required a new bracket, the optos were a different story Sega use ultra bright leds instead of infra red ones as bally/Williams use, I ordered a couple of spares from one of our suppliers but I couldn't make them work very well they were near impossible to line up the sender to the receiver.
The small boards are unobtainable so searching for other answers I came across a tip in using ultra bright orange leds instead of normal red ones luckily I had some left over from a previous project
fitting these made a big difference to the sensitivity and were much easier to set up.
The paddle wheel entrance opto has been an issue with Data East/Sega from day one as it was sited next to a VUK causing vibration's to upset the switch board position. Sega come up with an alternative switch to fit, a magnetic reed switch instead of the opto I managed to locate one in this country well pleased in that.

With all these problems sorted I tried a couple of games and had several switch faults appeared I did not think much of these at this time.
It was apparent that this machine had sat for along time unloved and in the sun as most of the playfield plastics had faded badly and had gone very brittle similar with the rubbers they just fell off, so a new set of plastics were sourced as well all new drop targets,a rubber set came with the machine.

Parts arrived and were duly fitted now play testing began the switch faults were popping up all across the matrix one fault was found with a drop target wire chaffing on a GI socket that cured 4 switch's on one row. During play when operating flippers phantom switch closures were happening
on rows 3-8 from what I could work out but they were all intermittent and they all stemmed from the use of the flippers, mysterious.

Reading up using Marvins guide and Pinwiki ,I tested the cpu board by shorting across the send and receive header pins CN8 - CN10 these all tested ok all rows all columns, so this ruled out the cpu board, so I turned to the flipper board this all appeared ok nothing stood out except it was not the board that the manual stated it should be, but it was factory as the warranty sticker had the same serial number as the rest of the boards. A service bulletin from Sega detailed revisions to the board that should be carried out to upgrade it to the correct revision for this machine this was done and still phantom closures happened.

Now to start on the only other thing the miles of wiring and the switch diodes (to be continued)

http://pinballrehab.com/1-articles/.../146-switch-matrix-theory-and-troubleshooting

Reading up on this on the above site I thought I better start looking for duff diodes on the switches and calling up for support from @Pinballsurgery
to help diagnose this fault so with emails going back and forth try this test that etc, like removing the return switch lines from the flipper board
the closures still appeared. You could operate say the left flipper 4-5 times nothing then on subsequent flips all sorts of switches would fire off
particularly the slam tilt, On the switch test screen you could see all the other switches operating when operating the flippers,weird or what
another post on a site recommended replacing the flipper coil diodes done that no change (looking at Marvins guide one of the illustrations showed the diode soldered in the other way round so I promptly thought I'd try it that way round on one flipper) big mistake wiped out two transistors on the flipper board bugger.

Even weirder if you took the plug off the CPU board at CN8 the send side of the matrix, operating the flippers still gave phantom closures showing on the switch test screen

By now we are scratching our heads everything was pointing to the flipper board somehow sending spikes up the switch return lines banging the playfield wiggling all the under playfield wiring nothing no closures and all switch diodes tested all ok.

Talking further to Mark @Pinballsurgery he agreed to pop over to my place luckily he is only about an hour away from me and brought his test equipment over
as I only have a DMM to hand, Mark checked over all the switches also checking the 5v logic supply from the power board all checked out, fine no power drops
but on putting his oscilloscope on the switch return lines at CN10 strange pulses were showing when all pins should read high. These pulses were there sometimes and then not, when you operated flippers you could see a small voltage drop on some of the pins enough to make the logic go low and make a closure we weren't sure. Still it pointed to the flipper board.

There seemed to be no logic to this fault as you could not replicate it and it was totally intermitant, but just before he left he tried a game and for two balls the machine appeared to behaved itself, then on the third ball it started again ,back to square one.

I thought id take another look on Sunday but was still going around in the same circles Mark suggested it could be EMI and asked to check all the earth resistances between the boards whilst doing this I started to probe at the wiring around the PPB board and as I touched the large cap C1 on the board it seemed to rattle
I then started a game and the machine played fine for 10 mins and then started to act up again.

Well it was the 100uf 160v cap at C1 on the PPB board the joint on the - end had completely cracked causing intermittent connection

I cant explain why this would cause the matrix fault perhaps someone else can
 
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