Space Invaders arcade game part 1

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I got this Space Invaders arcade game in for repair.

I made no promises because this is my first arcade game in a cabinet, and i have never worked with arcade monitors and power supplys.
Also Space Invaders CPU is an Intel 8080, which are somewhat hard to come by.
Not to mention the RAMs that are almost unobtainium (For me anyway), and appearantly often goes bad on these.
This will take some time.. 🙂

Measured voltages, and they were ok.
I then hooked up my monitor (Philips CM-8833-II) to the game instead of the monitor that is in the cabinet, and powered it on.
Garbage appeared on the screen, so the game is not booting.

The power supply i have on my workbench should deliver -5v, but when measured it only showed -4.2v, and i am not sure if that would hurt the 8080.
The 8080 is appearantly sensitive to the -5v supply, if it is missing, the 8080 are likely to be destroyed.
I will not risc that, så i will first have to find a solution for a power supply that delivers closer to -5v before plugging it in on my workbench and start troubleshooting.

Williams Jungle Lord pinball machine returns part 1

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It has returned! 🙂

New faults has appeared :

-The left magnet stays on when a game is started.
-The miniball sticks in a lane sometimes.
-One drop target does not drop correctly anymore.

Left magnet stayed on was a shorted 74LS08.
Removed, socketed and replaced.
Left magnet ok again.

Drop target that did not drop properly seems to be that half the sticker has come loose and sticks half way down.
(Bottom half loose.)

Williams Indiana Jones pinball machine 2nd repair part 2

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The left jet bumper and the right slingshot are now repaired and working.

I removed the power driver board and replaced all the components for the right slingshot.
Testing showed that it now works as it should.

Another problem is that the game sometimes ejects extra balls when playing.
It seems not to happen when shooting the balls “normally”, when just hitting random targets without locking a ball.
Switch matrix seems to be working and are registering all balls correctly in the ball trough.
I removed the two opto boards in the ball trough and looked for bad solder joints, but it looks ok visually.
Testing of the ball trough showed no issues, even when fiddling with the wires.

Further troubleshooting revealed that it only happens when locking ball #2.
When ball #2 enters the idol, the previously locked ball were released to the playfield because the idol rotates to make room for ball #2.
It turned out to be the yellow plastic idol rotor lock that had broken off, which should prevent the ball from going back to the playfield at this time.

I placed an order from the guys at free-play.se so it should arrive within a week.
Thanks Simon! 🙂

This should be the solution for the several ball issue.
But i can only be sure when it is replaced and tested of course… 🙂

Williams Indiana Jones pinball machine 2nd repair part 1

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This machine i repaired for about 1.5 years ago came back with some new faults that had appeared.

This time the left jet bumper and the right slingshot had stopped working.

The left jet bumper coil had a wire that were no longer connected due to vibrations.
Soldering it back on solved that issue.

The right slingshot coil was fried and were replaced with a new one.
Further troubleshooting showed that the TIP102 transistor controlling this coil on the driver board had burned.

I have now started replacing all the components in that circuit. (Total of 7 components)

Williams Jungle Lord pinball machine part 7 – Finished

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Finished. 🙂

A broken diode on a roll over switch made it not responsive.
Replaced that with a 1N4004 and it is back in business.
(The remains of the old one seems to have been a 1N4148.)

Funny thing when i troubleshooted the right magnet that did not work, i discovered that it did not seem to ever have been working from factory.
The playfield had absolutely no wear over the magnet compared to the left one that had wear over it.
And one end of one wire from the magnet looked brand new, and could not ever have been soldered in, it just hung there. 🙂
Soldered it in, and now it works as it should.

All that remains now is a final wipe of the playfield and putting the glass back in, and polish it, then it is ready to be picked up.

Williams Jungle Lord pinball machine part 5

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Now the sound board is finally working including speech.

Replaced the capacitors and also had to socket and replace both the CPU and the PIA for it to work.
(And also IC5 4050 buffer were socketed and replaced.)

All the boards now seem to work.

It is now time for the playfield, drop targets, switches, lamps, rubbers.

Williams Jungle Lord pinball machine part 3

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The Power Supply Board is now ready to be reinstalled in the game and be tested.
All capacitors are changed and all connectors are resoldered.
All fuses are also replaced.
A new connector for the GI were installed because of the previous wires soldered directly to the board.
A new fuse holder were also soldered in on the original spot instead of the external fuse holder that they did previously.

Unfortunately i had to solder in new wires for the incoming power because the previously modder drilled the original holes bigger to fit the larger wire they soldered in…
(I did not want to solder in a new connector that had no support from the hole itself.)