Stern Dracula restore; PART 2

[Mr Pinbologist]

Next I got stuck into the MPU board, on inspecting the pin headers I found the cause of some problems I was having with digits going out, which I initially thought would be the connectors. Some of the pins had bad solder joints. The pins were tarnished and had at some stage been sanded so I just replaced the pin headers.. no point in mucking about with dodgey connector pins I always say!! While I was at it I soldered on some long wires to where the memory battery connects to, and on the other end I fitted a 9v type battery snap to connect onto the battery holder that is shown in the second pic below.

These pics show the board installed and the 3x AA battery holder. Actually it’s a modified 6x AA holder. I soldered the diode into the backside that stops the MPU from trying to charge the alkaline batteries that will be fitted.

Still to be done, the ball shooter assy to be rebuilt, and one display with damaged segments to have a new glass soldered in. Also I’ll check and replace any corroded/tarnished connector pins.

[Mr Pinbologist]

Thanks for taking the time to post these excellent results Mitch

I'm sure everybody that reads your posts becomes even more inspired by doing so

Ever thought about doing a pin from the early to mid 1960s?

Thanks Tony. 

Yeah id definitely consider doing a resto on an early 60s pin if i came across one for sale.

[Strangeways]

simply superb Mitch !

I love your test rig - that would make life so much easier !

[Pinfan]

simply superb Mitch !

I love your test rig - that would make life so much easier !

 

[Mr Pinbologist]

Another update: getting close to finished now!  I removed the legs and repainted them again, in the same colour hammertone paint used on the coin door. Rather that strip them back I simply sanded them back with 400 wet/dry paper, gave them a wipedown with Prepsol, gave them a few coats of paint and refitted them to the cab once dry.

I’ve actually had the game powered up and running a few days now, checking everything. Just a few small issues that had to be dealt with, ie switch cleaning/adjusting etc.

The sound board had always had a few probs with some of the tones weak/distorted, especially during the cold weather, and ALWAYS on the 1000 point sound. After studying the circuit I figured it had to be in the tone generator circuits, around U17 (LM324) a quad op amp ic and its associated components. Three of the four op amps in this IC form the score tone generator circuits for the 10, 100 and 1000 point scores. Rather than muck round I simply replaced all the ceramic capacitors in these circuits with new polyester caps as well as the IC itself for good measure. I didn’t have an LM324 on hand so I used a TL074 instead, which is basically the same, having identical pin outs works just fine.

Next I repinned the power supply connectors where needed and used new housings for the connectors, to help improve reliability.

[Mr Pinbologist]

aww f**k!! forgot to resize that last pic!! sorry!!

[Mr Pinbologist]

Ball Shooter :

This was looking crappy so I removed the plunger and springs and gave the housing a sand back with 220 grit sandpaper, then 400 grit. As shown in the 1st pic I wrapped a 3/8’ drill bit in masking tape and pushed the shooter housing onto the drill bit firmly, and spun the drill at a slow speed while holding the sandpaper against it.. thus making short work of sanding!! A quick wipe with Prepsol and rag and it was given a few coats of acrylic primer.

When the primer had dried I sanded it again with 400 grit, cleaned it up with Prepsol and hit it with a few coats of acrylic white. While that was drying I mounted the plunger shaft in my drill and buffed the shaft and end to a nice shine. Then reassembled everything when the paint had dried.

One mistake id made when repainting the cab.. the cutout for the plunger assy had at some stage been enlarged/drilled out, so the hole was just visible with the shooter mounted .. Of course I forgot about this when I repaired the cab didn’t I??!! Anyway to get around the problem I cut out a piece of clear polycarbonate plastic to fit over the shooter housing mounts, and made it a slightly larger diameter than the housing itself, thus covering the hole. Next I painted the plastic on the back side that would be against the cabinet with the same colour paint as the cab.

Worked out pretty well I think, the average person looking at it would never know it wasn’t original unless they knew a bit about these games.

[Strangeways]

we share the same amount of attention to detail !

Love your work, Mitch !

[Mr Pinbologist]

Display repair: I had one dodgey display that needed a new glass. I ordered a couple of glasses that arrived on Friday (yesterday), so I got stuck into replacing the glass.

1st pic shows the display in question. 2nd pic, the new and old glass on the bench. I desoldered the old glass and fitted the new one then tested the display on my test jig. The display function lets me test all of the inputs to the display. It advances the digits 0 thru 9, and I have switches for the latch, strobe and blanking inputs so I can fully test the display.

[Mr Pinbologist]

While I was printing out the instruction cards I thought I might as well scan and recreate all of the information/ settings cards as well.

Hows THAT for attention to detail Nino??!!

[Mr Pinbologist]

And heres the game complete.. well except for the backglass, which I still have to do something with to make it look better.. hopefully!

Its so great to finally have this up and running again. 

In the meantime, I’ll set up the game into the lineup and enjoy playing it for a while and repair the backglass later on.

[Mr Pinbologist]

more pics..

[ajlaird]

Heh, heh, you guys are too much! Once again, superb work.

I can see why you guys need a few pins - otherwise you would have nothing to play while your restoration pins are tied up in the workshop for months.

[faza]

Display repair: I had one dodgey display that needed a new glass. I ordered a couple of glasses that arrived on Friday (yesterday), so I got stuck into replacing the glass.

1st pic shows the display in question. 2nd pic, the new and old glass on the bench. I desoldered the old glass and fitted the new one then tested the display on my test jig. The display function lets me test all of the inputs to the display. It advances the digits 0 thru 9, and I have switches for the latch, strobe and blanking inputs so I can fully test the display.

Hard to believe that this is the same machine fantastic job
Where did you buy the new display glasses from and were they expensive ?
I have four that either need repairing or replacing.
Cheers

[ajlaird]

And are you going to spill the beans on your test rig? Or is that a trade secret?