Hi,

I just picked up a Count Down. It's my first experience with a System 1 game.

I've come across some issues and am hoping to get advice/input from the group.

1) When I first got the game, the displays worked. I "tinkered" with some connectors on the CPU and now they no longer light.
2) I've been checking voltages, The Bridge rectifiers are good, the power supply is putting out +5VDC and -12VDC on J2. I'm getting 4VDC and 8VDC on J3 7,8.
But am not getting either 42VDC or 60VDC on J3 1 or 3.
3) I'm guessing that the attached picture is not a good sign for the CPU (corrosion?)

so.....HELLLLPPPPP!!!!!

thx
IMG_2626 (resized).JPG

Thanks,

As per Clay's youtube video, I'm taking ground from the 200mf cap that's just below the male connector. I'll double check, maybe the 1/4a fuse is blown, but it checked good before.

I'm hoping that I didn't blow the little transformer when I was jiggling connectors with the power on. I didn't see, hear or smell anything.

I'm considering a new CPU. perhaps the all in 1 board.

I'm going to be locked in a hotel room for a few days, maybe I can bring the harnesses with me and start repinning.

no comment!

but on a serious note....do you know what size pins to use? .100 or .156?

Thanks, That's where I was leaning

lol,

When I first moved into my house, I told my wife that I wanted a pinball machine. She said "OK, you can have one (1)" I'm up to 20 or so now.

She ignores it all.

Thanks. I was just about to hit the purchase button for the all in one board, but damn, it's expensive.

How would you clean up the corrosion? Vinegar?

I'm still trying to figure out why the displays stopped working

Thanks,

Maybe It's a bad ground? Should I be taking ground from the ground pin on the right connector instead of the capacitor lead?

I checked incoming voltage across pins 6 & 7 and got 79V

BTW, I'm an EM guy, not that much experience with SS, yet alone a System 1.

The thing that perplexing me about the displays is that they did work. I noticed that now, after the game had been off for a while, I turned it on and the #3 player display lit dimly for about a second before going out. Also, the heaters seem to work, I connected them to an external 6VDC source, and they glowed.

OK,

After going back and forth on what to do, order an all in one board, which seems the easiest but most expensive way to go, or order a new power supply and CPU, which is less expensive, but might not repair all issues, or repair the power supply and cpu myself, which is time consuming and may not work in the long run, I've decided to 1st repin the connectors and then recheck voltages and go from there. I suspect that I'll need a CPU as A1-J6 just slides right off of the CPU, nothing left for it to grip and I haven't had great luck when trying to clean up CPUs in the past.

Stay tuned....This may take a while!

Thanks,

I that's going to be my plan of action. right now, 'm trying to desolder the old battery. What a PITA!

Couldn't get to the legs. I had to cut the top of the plastic housing off and remove the batteries. Then I was able to grab the legs with some pliers and desolder them.

Thank you. Is it the same link?

Great!

I'm going away for a few days and won't be able to get back to the game for a little while. Boy I hate being away when I want to keep working on the machine.

Oh well, work calls.

to recap (no pun intended), here's where I'm at.

1) Game used to light displays, although no 5 second delay. Player 2 display was dim.
I jiggled some connectors on the CPU while power was on, I didn't play with the display connectors though. Then lost power to the displays.
2) Started running Clay's procedures, using your Spreadsheet.
The fuses are good, Bridge Rectifiers show proper resistance.
3) The 5V and 12V outputs to the CPU from the power supply are there and within tolerance.
4) No High Voltage output to the displays even though the input across pins 6 & 7 to the power supply is 74V.
5) The 4 and 8 volt output to the displays are there and correct.
6) I removed the CPU, desoldered the battery.

Here are pics of the CPU. Do you see ay reason to scrap the repair and buy a replacement?
Any thoughts one why no high voltage to the displays?

My plans are to start re-pinning connectors when I get back home. I'm keeping my fingers crossed that that will restore the high voltage, but am not optimistic at this point.

Thank for all of the help so far.

-W
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Thanks, I was concerned about some of those chips.

Yes, both the door slam switch and the tilt switches are/were open.

Now you tell me!

Thanks, There's an old timey electronics store not too far from where I live. I'm sure they have the tool. I know they have .156 connectors. I already have a bunch from a previous project.

Yup great guy. I may pick up new edge connectors from him.

Cool. I've used pencil erasers on Seeburg Jukebox formats. I'm wondering if that "we buy Lionel Trains" place on rt.46 in Parsippany would have them.

That would be great, I'm away from home right now. I'll be back in a few days. You're always welcome to come over, worse comes to worse, if we don't get this game going, we can play some pinball, hell we can do that either way.

Do you think this would substitute for a DM7405N as they are out of production. Mouser and Newark Electronics recommend them instead. I can always get a DM7405N on eBay if needed, but I for 1.91 I ordered the recommended replacement from Mouser.

https://www.mouser.com/ProductDetail/595-SN7405N

oops, Mouser recommended the other chip, so I ordered one. If you have an extra, I'd gladly use that.

Yup, Wayne Electronics. I called them today re: the pins, but he only had 10 pieces.

Guess what I forgot!. I saw the chips were soldered to the board, so didn't think of sockets. Maybe Wayne Electronics has them.

I can't believe the Molex brand tool is $22.00

I found that a probe from my multimeter works perfectly.

here's a thread...

https://pinside.com/pinball/forum/topic/stripping-battery-corrosion-with-a-strong-acid

Well, It's not exactly working, But the displays power up.

I cleaned and neutralized the CPU. I re-pinned A2J1.

I was still not getting high voltage, and now the +5V output was intermittent. Then I noticed that pin 7 on the input header was pushed in about an 1/8th of an inch. I pulled it out, and voilÀ.

I had given up and ordered a new Power supply, then figured this out about 5 10 minutes later. I went to cancel the new power supply, but tit had already shipped. I'm trying to decide to put in the replacement or keep the game original. I guess I'll keep it original if the CPU is good. If I have to replace it, I may as well replay both.

I won't get around to re-pinning the other connectors until sometime next week.

Stay tuned, and thanks for the support/help.

-W