Tuesday, 10 December 2019

Atari Space Riders Pinball (1978) - Part 4

So with the electronics and mechanical parts all seeming to be working OK, it was time to give the play field and all the parts a good clean. Time to strip it down and get rid of all that grime.

The worst part of the play field was by both pop bumpers.

So this is where all the play field art was hiding!

 Putting the kitchen sink to good use!

It was a great day to dry all the parts outside

I ordered a selection of cleaning products and some new lamps, balls and rubbers from Pinball Heaven. After giving everything a good clean I used some Novus on the plastics and Milwax on the playfield. The metalwork had a quick polish too. At this point I started reassembling it all using loads of photos I'd taken fir reference.

At this point I was all set to put the legs back on, move the game in to place and invite some mates round for a game or two, what could go wrong? Being an Atari pin, my work was not yet complete...

Monday, 9 December 2019

Atari Space Riders Pinball (1978) - Part 3

Time to sort the score displays out. I was expecting this to be a difficult fix and that was proved right, I spent a good amount hours getting to the bottom of this fault, not being someone who just shotguns a stack of parts to fix a problem, I like to know why something is faulty and find that cause.

Atari describes the score panel as a Gas Discharge Display. They are a glass based vacuum tube which are made up of seven segment displays. Using 180 volts DC, gas (likely Neon) the segments are illuminated, if you take a look over google or Youtube there is little info on the panels Atari used most of the content is about how they can go faulty.

With my panel the Player 1 and player 3 score digits were either missing or randomly flashing.

When the game boots all segments should illuminate and the 1,2,3,4 player up selections should scroll. Here's what mine looked like. player 1 and three score was missing or corrupt, 1st up didn't light up and 3rd up was randomly always flickering.

The 1st thing to do was remove the plastics and check that the glass panel was correctly aligned with the sixty or so pins that connect to the pins of the circuit board. Unlike other photos and videos I've seen, mine looked complete and I would say had never been touched, there were metal clips with silicon holding them in place.

Once screws were removed and the clips released I removed the panel:

As you can see below, the copper contacts didn't look healthy, checking continuity on the pins some had broken connections. Again out came the self adhesive copper tape and I re-pinned all the connections.

An hour later I had cut a lot of tape and had it nicely lined up, continuity was now good across all connections.

At this point I removed the score PCB which is mounted in a plastic case that connects to the display itself. I tested and measured most of the components (resistors, diodes and transistors) All of those were good, I found a few suspect solder joints so reflowed them and put the bits back together.

As always happens when you put load of effort in, nothing was fixed and the same fault was present with the scores... After a bit of sulking and some more thinking I decided the fault could now only be the display itself or the Driver IC's for the segment displays. I took the assembly apart and removed the PCB, I removed the four driver IC's and fitted sockets, I'd marked the IC's and swapped their locations to see if the fault moved.

As can be seen below, with IC's I believed to be good moved around, player one and two lit up and displayed correctly. 

Off to eBay to source some replacement, a few days later I had a package with four new Driver IC's once fitted, All the scores displayed correctly and I had a quick four player game to confirm they were working correctly.

At power on, all segments light and the player up number scrolls, this was now all good.

With hindsight I spent more time on this that I needed to, I could have shotgunned the IC's once I'd confirmed the voltages were correct. The work I've done repairing the copper contacts should now give a lifetimes worth of play without issue! Who am I kidding when trying t o keep a 40 year old machine running...

Next up is the play field; time to remove all the plastics, metalwork and anything that can be removed from the top.  I plan to give it a good clean, and fit new rubbers all round.

More photos and less waffle next time.

Saturday, 30 November 2019

Atari Space Riders Pinball (1978) - Part 2

So I applied power and the pin sprung into life, well not fully working but there was no magic smoke at this point so I'll mark this as a successful power up!!

Even thought its a bad photo you can see there are some lights on the playfield, I triggered the coin switch and the the game would play, albeit looking a bit dim, the scores were also messed up and not showing correctly, so these would be the next two jobs to look at.

The issue with the lights was the first thing I set about looking at, after reading the manual and looking at the schematics, I understood that the Aux PCB had transistors that combined with some logic signals form the main CPU PCB controlled the lights, using the wiring diagram I worked out which lamps were not working and referenced that the transistors on the AUX PCB, using a logic probe I could see there was only one transistor working correctly, the outputs of the three faulty ones were being held high. Whereas the working one was pulsing a digital signal.

I ordered four transistors and when they arrived set about replacing them.

Transistors removed, clearly they generate a lot of heat!, the copper traces they connect to were in a very poor state.

I used some copper adhesive tape to make some replacement tracks, these were then tinned

I then tinned the copper making it ready for the new transistors.

Transistors soldered in place, some original capacitors were also tidied up and refitted.

New transistor installed.

After refitting the PCB the light display worked fine, with attract mode cycling through different patterns of lights. The game was also a lot brighter to play and further test. :)

Sunday, 22 September 2019

Atari Space Riders Pinball (1978) - Part 1

Disclaimer: This is my 1st pin, so go easy if any of my terminology isn't quite right. :)

I do own an Atari Video Pinball arcade so I've been a virtual pin guy up until now!

Purchased from the USA based on these photo's, sold as complete but not working.

So it arrived in the UK and was dropped off to me by Martin the deliveryman.

The bolts for the legs had gone missing somewhere along its journey so for now it had to sit on the floor.

Upon lifting the play field it was nice to find an original bag with the manual, wiring diagram and game instruction and credit info cards.

At this point I lifted the playfield and decided to check all the fuses in the game, surprisingly all were the correct value and still intact. Like the Atari video games, the input power supply can be changed by rewiring on of the Molex plugs attached to the power supply, its used to change the routing of the mains supply through the primary windings of the main PSU transformer. I used the wiring diagram to re-pin the connector for 230v AC input.

Next up I removed the CPU PCB to give it a once over and look for any signs or failure or damage, on these Atari games, the Solenoid and lamp control circuits are part of the same PCB. Straight away I could see there was an Operator bodge in place with turned out to be a control line for one of the lamps. (The thick wire between the two connectors with white cables)

The wire from the main harness has broken an instead of fixing it properly a wire was soldered to the PCB and them linked to the broken end of the loom. The connector pin was soldered back together and then the wire removed and the trace that had been used repaired.

At this point I re-fitted the main PCB, for luck I removed and reconnected every connector I could see in the cab and decided it was time to plug it in and see what happened...

To be continued...