Sharpshooter help needed

bongoben

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Alright, so last summer my father picked up a non-working Sharpshooter pin with the intention of working on it as a winter project. Since I am, for all intensive purposes, his pinball tech that means it also became my winter project. Due to a million unforseen issues last night was the first time I got to stop by his place for us to take a look at things. When we picked it up the MPU-2 pcb had some serious battery acid damage so I recently picked up a nice replacement pcb for him from a KLOVer. I was following a walkthrough on testing this game I found online (can't recall the website right off hand as it's bookmarked at his house). So, here's what we found...

Started off the night with everything unplugged from the power supply pcb. Got the correct readings at all of the test points and on the filter cap although I believe the filter cap may need to be replaced as I assume it is the original.

Plugged in the MPU-2 pcb to just the J1 connector. Tested the points T1, T2, and pin 3 on J1 (I believe they are titled T1 and T2) and all looked right on. Pin 3 on J1 was just shy of 30V but the manual and the repair site we were referencing both said it should read at 24V +- 6V.

When we powered the game on fully hooked up the first time we got the start-up static then a bit of a song. I should mention that the new MPU-2 pcb I received had Coney Island roms on the MPU-2 but on impd it says these are the same rom files as Sharpshooter so I left these in for the first power-up. The dips were set on freeplay so I hit the start button and got about 10 seconds of a song then nothing. This song replayed each time I hit the start button. I believe I got 1 LED flash that first time.

I checked a couple other test points to see if power was getting elsewhere on the MPU-2 and SDU pcbs. It was. I powerded down to swap in the 3 Sharpshooter roms and powered back up. This time I got the start-up static but no song and nothing happened when I hit the start button. No LED flashes. The only thing that happened was a light on the upper left side of the playfield blinked on and off repeatedly.

Reading the testing walkthroughs the next steps I saw were that I had to test the reset spikes (or something like that) at different points on the MPU-2 pcb. I believe it was on different pins on U17, U10, etc. Honestly, I am unsure of how to do this. Anyone have any pointers? Does this require an oscillator? I did try swapping out the chips at those two points with the ones from the original MPU-2 pcb but there was no change.

At one point when I powered the game back up I got nothing. No power at all. No readings on the power supply pcb. I checked the power coming into the game at the molex connection as well as at the switch and everything was fine. Checked the power at the bottom of the main fuse and got 30V and at the top I got nothing. So I replaced the fuse and the power was going through but still no activity in the game. So a couple possibilities as I see it...

1) The big filter cap needs to be replaced.
2) The bridge rectifiers need to be replaced.
3) God only knows......

So, this is where we sit. I'm hoping to be able to make a weekly stop at his place to work on this game but I would like to have any pointers going into my next tech session if at all possible. So here are my questions...

1) Where would you recommend I go from here?
2) Where can this big filter cap (10,000 - 15,000 mdf 16V) be purchased?
3) Where would the best place be to pick up some new bridge rectifiers (25A 200V)?
4) How do I do these "reset spike" (or whatever they're called) readings on the MPU-2 pcb?
5) Where would you recommend I go from here?

I'm not completely lost with this game, I just know that I don't have a ton of knowledge on pins and worry that I'm missing something completely obvious. So, thank you in advance for any help you can offer.

On a lighter note, I love working on his T2 pin. We just ordered flipper rebuild kits from marcospecialties and I'm looking forward to installing those.
 
also to note... I do have access to a cap tester which I neglected to bring over lastnight. I will be including this in my testing next week.
 
You can get the BR and cap from Bob Roberts or any online parts jobber like Mouser or Digikey. As for the reset spikes, they can be seen using a logic probe. You shouldn't need an o-scope unless you are looking for voltage levels or the shape of the signal.

Personally, I'd check all circuit boards for cold solder joints, replace any suspect headers/pins and see where to go from there. The machine does have the correct number of balls installed and you had the coin door shut when you tried to start a game right?
 
You can get the BR and cap from Bob Roberts or any online parts jobber like Mouser or Digikey. As for the reset spikes, they can be seen using a logic probe. You shouldn't need an o-scope unless you are looking for voltage levels or the shape of the signal.

Personally, I'd check all circuit boards for cold solder joints, replace any suspect headers/pins and see where to go from there. The machine does have the correct number of balls installed and you had the coin door shut when you tried to start a game right?

Unless I missed them it looked like Bob had only the 35A rectifiers... are these like caps in that the amps must be the same but the Voltages can be higher than called for? I completely blanked on mouser... thanks, I'll look there.

Can do on checking for cold solder joints. Another thing I never thought of (I blame the 20+ hours of weekly overtime I've been pulling for the last month on my not thinking to check the obvious things). Balls are right on and coin door was shut.
 
On a BR you can always use a higher voltage rating, just like caps. I am not certain about the amperage but I believe you can go higher on it as well. The problem I can see with higher amperage BR's is their size (and cost too I guess). The higher the amperage rating the higher the relative size due to an added need for heat dissipation.

Is this the site you are using to guide you through repairs?

http://www.pinrepair.com/gp/index.htm

It is pretty comprehensive and should help answer almost all of your questions.
 
if you havent gone to this site, use http://www.pinrepair.com/gp/index.htm for repair info.

first, the sounds that you should hear upon startup are a lightning crash followed by a rattle snake.. (or the best attempt at sounding like that ).

when you press the button to play a game, you do get a short tune..

but that is all after the fact.. what you need to concentrate on is looking at the LED on the MPU.. if it flashes 6 times upon startup, then your problem is likely beyond. do you know if the SDU or LDU work 100%?

power it up and then go into test mode (button inside the coin door)

here are the test modes (keep pressing the button and the test mode # will appear in the ball/credit display- just be careful and remove the ball if the playfield is propped up and you go into solenoid test as the first one kicks out the ball):
Game cycles only about 10 CPU controlled lamps during attract mode. Ones digit in score displays is always a zero.
  • 01-11 = Game Audits.
  • 12 = Lamp test for feature lights.
  • 13 = Display test (ones digit alway zero)
  • 14 = Solenoid test.
    • 010 = Q6
    • 020 = Q16
    • 030 = Q7
    • 040 = Q14
    • 050 = Q4
    • 060 = Q17
    • 070 = Q5
    • 080 = Q15
    • 090 = Q12
    • 100 = Q13
    • 110 = Q3
    • 120 = Q10
    • 130 = not used during diags (possibly mechanical coin counter).
    • 140 = not used during diags (possibly mechanical coin counter).
    • 150 = not used during diags (possibly mechanical coin counter).
    • 160 = flipper relay Q19
    • 170 = all CPU controlled lamps On
    • 180 = all CPU controlled lamps Off
  • 15 = Switch test.
 
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