Been working on a MH and finally brought her home last night. Worked Till late and again this morning and had her nearly 100% working. Thought I’d hit a home run.
Then I took a lunch break and left her powered on.
When I came back half hour later the displays are out and game will not boot up

I’ve pulled and replaced all 8 fuses (6 on the Rectifier board. One on the SDB and one under the playfield.)

The small one on the SDB was empty and one end cap was loose. (it’s a 3/16A. And it’s a 1” long fuse. So I only have a 5A in that size. I’ve put that in just to try to get it working again)

When I power her up I get the 7 total flashes on the cpu board and the small relay cube in the SDB clicks. Then nothing No music no start / boot up.

It was playing All drop targets and saucer working All scoring Able to use the diagnostic switch and got just about all working. Now nuttin

Any suggestions or some tech advice on resolving this one?

Thanks! Yes took that out. ASAP I understand that to be for the displays so they’re totally out now ( was getting a zero or two of them on player one for a while there) checked the fuse under the play field replaced it just in case

Coin up?

I don’t know how to test those. I have a dmm but which test points should I be testing ? It looks like there are a few on each board

The SDB was just sent and it was all tested before which is what helped bring it to life (and replacing a 4A fuse). Just for reference

No testing the boards. Which test points do I use and what should the readings be?

Great info, thanks! I did find an 8AG 3/16 Fuse! That was like finding a needle in the hay stack (they're on line, but I wanted to find one today, so I can get back to trying to fix her)

Looking over the link, I am getting the immediate flash, then 6 flashes on the CPU LED. So I'm not getting that 7th flash. I'll get home later and start using the info in the link above to start trouble shooting.

And no, I didn't re-pin any connections. There was no green slime and they all looked clean and good. Although one red one did slip out, but was pushed back in. Again it all worked for over an hour, or two. Then when I left for 1/2 hour to eat, then she wasn't responding.

So possibly these connections need worked over.

I'll keep everyone posted...thanks!

ahh, another good idea. I'm thinking the heat from the game did something...possibly to a connector, conductor, or even a chip like you're stating.

As a newbie - I'm taking this as one of the black small chips on the CPU/MPU board? For some reason I thought those were all soldered on, these just pull out and push back in?

I’m getting 120v on TP3.

Pulled chip at u10 and connector J4 per the reference docs above. (First chip so yes thought I was going to lose it getting that back on. Lol).

Now down to just 2 flashes (after the initial flicker) and reading zero on TP3. Ugh. Think I’m going backwards ???

Pulled chips at u8 and u9 (checking really to see if by pulling and re-setting I get contact).
Question - is the orientation of the chip an issue or can they go in either side up? (U9 didn’t have writing on it so I did install with the small dot on the bottom left as one of the others )

Verified no legs on the clips were bent over and all seem seated correctly

Relooked over fuses etc

But still now at 2 green flashes

Ahh. Notch to the left. Then yes it’s in correctly. Whew!

Think I’ve done something wrong in pulling these chips? To go from 6 down to 2 now? Or is this narrowing it down?

I’ve looked u8 & u9 over several times as I had one pin to curl when it wasn’t set properly. So now worried I’ve messed something up worse than when I started. But they look ok now. Ugh

Happy new year!

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Yes and I made an error for :
Tp1 : 5.2
Tp2: 13.3
To3: 21.7

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Tp1 & 5 I’m getting same reading. Tp4 I’m getting 40. Pulled and cleaned u8 chip.

Same Pulled all connections except j4. Still flicker and 2 flashes

And sorry. I was putting my black lead on a ground. Let me check now

5.1, 13.08, 21.8. Looks better thanks.

Do they sell individual chips or chip sets? Change one means change all?

And can leaving it on, after not working for years I’d say , burn these up ?

I’m getting 4.6-5.2

Yes. It was going to 6 flashes before I started reseating chips. Lol

Thanks That’s where it originally started when I brought her home. There was a 4A fuse blown on the rectifier board. Thinking it was this again I’ve replaced all fuses through out (before the chip issues today)

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I have and “MDL 5A”. Is the MDL correct? I see AGC. AGX. My main thought was matching the Amperage?

Sorry. Siri. I have a MDL 5A fuse in there. But I’ve seen other fuses with the other accronyms

https://itstillworks.com/difference-between-mdl-agc-fuses-7337905.html

MDL is slow blow. Aha. Should I find an AGC fast type? Looks like I’ve done that a few times

Should be receiving the chips today, will plug them in as soon as they hit the door step. Hoping this is all the issues, we'll see.

I've said it before, from the lady I've bought this from (and her late husband) to the pinsider sending her the replacement SD board, to the other pinsider sending me these chips - this is a game of love. One that I'm not flipping, one that will stay in my so called collection. Loved the look of it, and playing it!

Amazing peeps here on Pinside! (and now that I'm looking at my PM's, I was supposed to send a man some photos of my shuffle bowler...so I have not paid it forward...ugh, my bad!)

I'll keep this post updated, as it's also been a labor of love!

Wow! What an update here- spent the day with “The Wiz”! Now I know why they call him that! Just an amazing day of learning - so much on these SS machines. Can’t say enough for all the help from everyone here - thank you !

In a nut shell some chips were bad a lot of connections both on the boards and the pin connections. Etc. this thing needed a lot of TLC!

If I could post a video , the first game was played by my youngest granddaughter and she scored big time and got the match to work !

Mata Hari is back in action!

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