Stern Dracula restore; PART 2

[SPURR]

Super professional job as usual Mitch. Ive got two questions 1. after you paint the last coat over your stensil when do you lift up your stencil ? straight away.
2. Is that a Fender amp in the back ground of your pix's ?

[Mr Pinbologist]

Thanks for the kind words Mark.

In answer to your questions...

depending on how many coats were needed to cover, usually betwen 10 - 15 minutes, i always use enamel paint for this. the more coats i have to use, the longer i leave it before removing the stencils. but its NEVER much longer than about 15 minutes.

Yes... Very observant of you!! its a fender amp sitting on my bench.. only a solid state one unfortunately, a Pro185 belonging to my band mate, in need of a few repairs.

[Strangeways]

I LOVE your idea of using the hammer finish paint on the lock down bar assembly 

I might have to steal that idea for a Stern I have to do later on down the track.

Brilliant work as always, Mitch 

[Mr Pinbologist]

Coin Door:
While the backbox base coat was drying, I got stuck into the coin door, totally dismantling it then stripping the old paint with the clean n strip disc in my drill. Then it was wiped down with Prepsol and sprayed in the same hammer finish paint as the legs. Upon checking the colour, I realized after looking at a few pics of other Stern games that the hammer finish paint colour id used was too dark So I then decided to go for the same White Knight brand hammer finish paint Nino used on his Stern Meteor coin door.

So I searched all the shops local to me (the nearest Bunnings to me is an hours drive away), I ended up at my mate Ricks place of work (who custom mixed some of my playfield paints for me), and found the right paint. So it was then a matter of stripping the coin door… again!! and respraying it in the new colour. Id also sprayed most of the parts inside in the darker colour, so rather than strip these I left them as they were. After the paint had dried I reassembled everything and fitted the door back into the cabinet. The coin chutes I polished with Autosol polish before refitting to the door. Initially id painted the door bolt heads but decided to buff them to a nice shine instead. To do this I put each bolt into my electric drill and spun them, while first holding a piece of 400 grit sandpaper against them to clean them, then a piece of rag with Re-po paint doctor polish to buff them to a shine, this stuff works a treat for this!! Plus it’s a wax based polish so it should help prevent corrosion.

In these pics the legs still have the darker colour paint on them but they will probably be removed and resprayed in the lighter colour.

[Mr Pinbologist]

Backbox Stencilling:

[Mr Pinbologist]

Power Supply and Transformer:

First thing I did here was to remove the transformer from its metal housing and remove the circuit board from its metal backing plate, and gave these metal parts a thorough clean and to remove some surface rust that was present with the clean n strip disc. Then I gave them both a coat of hammer finish paint and sat them aside to dry.

Notice in the 1st pic the threaded insulated spacers I fitted in place of two of the nylon mounting standoffs. This is something I did on my Lectronamo power supply to give the board a more solid mounting, since the boards normally rely on the original rectifier bolts for this. Otherwise the board can fall off from the mounts. I bought these from DSE.

Next I rebuilt the power supply board with new 35 amp bridge rectifiers, new header pins and performed all of the upgrades as per the Marvin website. I usually use the spade terminal type bridges and solder paper clip wire to the terminals so they can be fitted into the board.. a bit of extra work I know but these bridge rectifiers are pretty cheap and quick and easy to obtain from DSE so that’s why I use them.

Also before fitting them to the board I fitted some heatsinks to each bridge. These cost me nothing as I raided them from a dead TV switchmode power supply board from work!! I trimmed them down a bit so they’d fit neatly and bolted them on with some heatsink compound smeared on for good measure. Last pic shows the power supply fitted back into the backbox. I tested all the voltages coming out of the supply.. the solenoid 43 volt was missing but I quickly traced that to a solder joint on the AC side of the bridge that hadn’t tinned with solder properly.

Next on the to do list… ground mods etc for the solenoid driver and check voltages before connecting any other boards up, a few connector pins to be redone, fit a remote memory battery lead to the MPU board. Also have to fit a new power switch that was missing (the wires had been joined and taped before I bought the game)!

No long to go now!! 

[tonyt]

Great work Mitch, looking really nice. Hopefully will be able to apply your methods, particularly with the stenciling to one of my own restorations one day.

[ajlaird]

The coin door has come up really nice, and the backbox stencilling has worked a treat as well.

Looks like you have put in some big hours with this one but I can tell the result is going to be very pleasing.

[illawarra_steelers]

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?

[SPURR]

What would we do with out you Mitch?

[Strangeways]

Exception Cabinet work, Mitch. Looking great.

A question regarding the Power supply upgrade. I notice the housing is an original one. Did you replace the trifericon pins ?

The picture of the door mounted in the cabinet is fantastic. I love your work, Mate !

 

[Mr Pinbologist]

Exception Cabinet work, Mitch. Looking great.

A question regarding the Power supply upgrade. I notice the housing is an original one. Did you replace the trifericon pins ?

The picture of the door mounted in the cabinet is fantastic. I love your work, Mate !

 

havent replaced any connector pins/housings yet, thats on the 'to do" list

[Mr Pinbologist]

Made some more good progress today in getting this game done. 1st pic shows the playfield ready to go into the cabinet. Note the protective felt strip on the side of the playfield… an idea borrowed from, I think it was one of Nino’s restores? where he put felt strip on the side of one of his playfields to protect the newly painted insides of the cab?? sorry if I got that wrong. Anyway the idea came from on here!! 

2nd pic shows the solenoid driver board with all of the grounding mods done as per the Marvins repair guides. The filter cap C23 had already been done on this board and had a 15’000uF fitted, so no need to change this one as it looked near new. I fitted this board into the backbox, connected it up and switched on and checked the voltages, all measured fine, as they should because the game was working before I dismantled it.

[Mr Pinbologist]

 These pics show my home made board test jig I built to test bally and gottlieb driver boards and displays. With this I can fully test both bally AND gottlieb 6 digit displays, bally lamp driver boards and gottlieb sys 1 driver boards. The top rows of LEDs connect to each output of a stern/bally lamp board, and the bottom rows are for the gottlied sys 1 driver board, each LED goes to an output driver transistor or SCR. The gold strip in the middle has the edge conector for the sys1 board behind it. Each LED is labeled with the board reference number for the output device its connected to.

Anyway for the bally/stern board, an internal binary counter drives the ic’s on the driver board, turning each output on one at a time in each of the four banks of leds, one bank for each decoder ic and its output devices on the driver board. the fore red switches at the top let me blank each bank of leds to test the decoder ic’s and the output SCRs. The 5th switch (strobe) lets me stop the decoders on a particular output in the four decoders, as can be seen in the 2nd and 3rd pics, thus its telling me Q43 on the driver board isn’t switching.

Last pic shows the output working after I replaced the SCR Q43. the board was then ready to go back into the machine.

[ajlaird]

Nice one - are you going to release a schematic? Pretty please?