Dolly – rectifier board

So, those waiting along with me with baited breath for Dolly to come to life will have to wait a few more days.

I replaced the verified boards in the machine, and everything continued to work as it had previously.  I looked at the rectifier board – and tried to swap out the F1 fuse. No joy.

as-2518-18aI tested all the test points (TP1~TP5) on the board, and of course the first one is dead – and it of course links directly to feature controlled lights – which is the problem.

Now I’m faced with removing the board – which is itself soldered directly to the power supply. What a stupid decision – why didn’t they just add one more connector?  Well, they did on later machines. But not this one.

Looking at the image there is one big black square, and three smaller squares with circles within them.  One of these small squares is the bridge rectifier that is dead.

I’m thinking I’ll have to do one of 3 things
as-2518-back

  1. Remove the board, and replace the three small  bridge rectifiers. The problem is they are undersized for the task and fail. So, I’ll need to use larger parts, and mount them to the front of the board, and re-solder the wired connections when done.
  2. Remove the board and steal a working one from my friend Kevin –
  3. Remove and replace the board with a solid state option for $65 bucks from someone like www.pin-logic.com.

Because I’m terribly frugal – it will most likely be option 1 or 2.  I do have some bridge rectifiers in a box of parts – so, I think I’ll most likely do option 1.  If I destroy the board then 2 or 3 ;).

Fingers crossed, but hopefully not the wires.

 

 

Dolly – she’s coming to life

The continuing saga of the Dolly Parton pinball machine…

I bought an Alltek MPU which arrived last week.  Immediately I swapped the old MPU out, and with fingers crossed I turned on the power… (baited breath inserted here)

The game scores, and plays – but the feature lights aren’t working… darn it! (something else inserted here).

After reaching out to GAPAS (http://www.gapas.org) with requests for ideas, my friend Kenny came over to help with some testing. Unfortunately, we couldn’t quickly determine where the problem was. So, we took the boards (MPU and Lamp driver) over to his house and dropped them into his Six Million Dollar Man (painfully held breath) and  EVERYTHING worked!

This is great news!  I was afraid something was wrong with the Lamp driver board and I’d be having to purchase something new, or the new MPU itself was faulty.  But as they worked fine on his machines – I’m back to looking at the Dolly game itself.

Unfortunately, I left Wednesday for a vacation, and just returned home Sunday night [Well, not really unfortunately – it was a great time in Cancun].  I hope to have time tonight to put the boards back into the machine, and check the leads that Kenny sent me over the week and weekend.

I’m very excited to hopefully add Dolly back to the land of the living – she’s never been a good zombie and this half life living dead isn’t what I hope for her.

Mentally There… and my ongoing Arcade Repair

I’m now terribly happy I put together this blog.

After trying so hard with the Dolly MPU board and being so annoyed at the dramatic failure my efforts returned I found I was not in the mood to work on my machines for a few days.

Then I got distracted and a few days became a few months.  And this is where my happiness starts – I have an exact record of what I identified on each arcade game and pinball machine, and happily I don’t have to re-discover the issues on each one.  THIS is huge on projects with potentially so many pieces to manage.

And now that I’m about over my pride and annoyance at the failure with Dolly; I find myself ready to start thinking about doing more to bring things to life again.

So, HOPEFULLY in the next week or two after these next guests come through I’ll be ready to get back into the swing of things.

TO DO:

Find instructions for my arcade game Missile Command CPU board – or how-to troubleshoot it.  I’m thinking it is the power section that I should start with anyway and go through it logically.  It would be ohhhhh so much easier if I actually understood electronics somewhat…  😉 But I’m a dynamo at following instructions. If I could find a diagram that breaks down the sections of the board perhaps.  A picture with grouped items outlined – Power, Ram, Video, IO, etc – this would make it easier for me to discuss what I’m looking at on any given day.

A friend told me there was a ‘bullet proofing’ guide for ATARI games of this era (1979ish) regarding the power systems.  I wonder if that would provide me the guidance I need – any readers familiar with this?

Thanks those of you who have been patient and still are tracking at all what I’ve been trying to do.

D.

Dolly – It’s Alive (again)!

Dolly Parton Backglass

Dolly Parton Backglass
The other day I was thinking about the 20k resistor that I didn’t have – and got to thinking.  “Can’t you run resistors in series or parallel to adjust the net value?” I thought to myself.  So, I called my dad as I thought that if you put them in series you then added the ohm rated resistance values together.

I have an 18k, and I have some 1k’s – I need a 20k…  So, I soldered the selected ends together (after calling my dad to verify) and put them in. Hoping against hope – I put the board in the machine and gave it power.

I had the machine  where the LED (which indicates boot status success/failure) to be constantly on. I counted this as progress.

Tonight though I had some more time

So, I re-verified all the continuity points for my U8 IC on the MPU.  And of course found a number that needed to be updated.

If you are a follower/reader you know that I recently determined there was more corrosion damage than I had originally thought (in my haste). So, I spent the past few times that I’ve had free to remove that, and install a socket for the U7 chip.

After this process the LED got through the flicker and first flash.  YAY – there needs to be 7 successful flashes for the game to boot up as each one indicates a phase completed.

Energized with my success I realized that I had not verified continuity on the U7 socket that I had replaced. And remembered belated that there was a trace that had evaporated in the corrosion cleaning phase under U7.  I found one leg of the IC completely isolated from the game – figured what points it needed to connect to.  Verified each of the other 21 legs on the chip – and after 2 hours of testing and soldering I decided to hold my breath and plug it in again.

Watching the LED like a hawk – it flickered.  Then flashed… once..  after a bit of a pause it flashed again, and again, and again, and again, and again, and again – and then there was a sound sequence, and the scores lit up.

SUCCESS!!!!

The game is now in the same playable state as it was when I received it – but it not longer has the battery leaking more corrosive gasses and destroying the game.  It now really looks like  a Frankenstein machine with trace wires crisscrossing all across the back.  It isn’t pretty, but it is working – and I didn’t have to spend $200 to replace it.  I can live with not so pretty when no one will see it unless they pull the board out of the game.

Now.. time to run down the switch problems…  (next post)