It's the OP's photo you saw. And he said it was a new Altek MPU.

You're right to request photos of the connectors--that's one of the things I'd check. I don't have they game, unfortunately.

That garbled mess on the screen could be a RAM issue or a ROM issue on the vidiot board.

Normally, when the vidiot board boots, it verifies the ROMs. However, I'd double check those and compare them yourself to the ROM files with an EPROM burner.

Also, make sure the ROM chips are in the right sockets. It's easy to play musical chairs with them if they're not labeled.

Yes, it sounds like it. Check those IDC connectors. It might be time to repin them.

Oh, I just noticed the gibberish on the screen. I thought it was blank earlier and that was just a reflection when I saw the image on my phone.

I haven't encountered that issue before.

However, it still does point to something in granny cabinet as being the problem if the MPU and vidiot deluxe board booted properly elsewhere.

What happens if you completely disconnect the driver board?

connector issue most likely

Have you ruled out the possibility of an issue with the monitor?

Have you double checked all the connectors you re-did and compared them to the schematics to make sure all the wires are in the correct places?

I have fixed this issue before. Three possible solutions. Change out the power supply brick, least likely. You grounding out somewhere, most likely. The oddest one was a bad coin selector switch. Try removing connections there and then from controls and see if it boots. This is a common Arknoid issue as well.

Just checked pinrepair's guide for Bally mpu boards, and here's what it says:

Sixth Flash Completed*:
The Fakers Guide: a sixth flash means the PIA at U11 (6821) and the U12 timer (5550 chip is good. No sixth flash means either PIA U11 (6821) or its socket is bad, or the U12 (555) timer is bad. Lack of the 6th flash (five flashes only) can also mean a problems with the zero-crossing detector. Often this is the MPU board's R113 resistor (2k ohm, near the J4 connector) is open. This resistor takes the 43 volt DC coil power to the zero-crossing detector circuitry and normally runs hot. Hence it may eventually go open, so check it if only 5 flashes from the LED are seen. Thanks to Ray J. for this tip.

Ah, i see what you mean. That is weird! As you said, it definitely appears to be something specific to the granny cab. Have you tried capguntrooper's suggestion?

The last MPU LED flash is related to the zero crossing power detection.
According to the schematics on this -133 MPU board, the signal used for zero crossing detection is the switched illumination power (6.5V) that enters the MPU board at pin 15 on connector J1 J4. This game does not use 43V for zero crossing like Ballys -35 MPU games.

Biffbar already mentioned details of this in post #02 above.

Are you measuring around 6 volts at TP3 on the MPU board? (this is the zero crossing signal) i.e. is the 6.5VDC switched illumination power in this cabinet reaching the MPU board?

Arrggh, sorry I keep confusing MPU J4 with J1. I've edited the post above and changed it to pin 15 of J4.

This is a tricky one with the poor quality scan/schematic, not helped by the vague details in the schematic.

First diagram below is the online scan of the Granny and the Gators -133 MPU schematic.
Second diagram is a clearer scan of the GoldBall -133 MPU schematic.

Pin 15 on J4 of the MPU schematics is listed as "SW ILL ØA". This is the Zero Crossing input signal to the MPU board.
If you look at the "wiring diagram" in the schematics, the MPU J4-15 is listed as a solid grey wire "ØA From Playfield". On the same wiring diagram look at the three top left tables showing intermediate connectors in the harness. You will see the "ØA Z XING" grey wire on the left most table, the third left table also has a grey wire marked "POWER LITE" from "ØA" which I presume is from the transformer/rectifier board which unfortunately is not in the online schematics.

If you look at the schematics on any Bally -35 MPU board, pin 15 of J4 is listed as 43V. Not the case with the -133 MPU boards.

.
Granny and the Gators -133 MPU schematic
GoldBall -133 MPU schematic

There's a diode (CR52) between these points, Pin 15 of J4 should be measuring slightly higher.

What voltage do you measure along the common bare wire connected to the base of each switched feature lamp on the playfield? 5.3V or 6.5V or other? We're after the power voltage on the switched feature lamps, not G.I. lamps.

After the MPU LED flashes on boot up, does the MPU LED then go dim or stay off completely?

If you've got a logic probe, does it indicate pulsing at pin 18 of U10 on the MPU board?
On the MPU schematic at the top where the Zero Crossing Detector is, do you measure approximately the correct voltages around U14 as listed on the schematics? See below:

Do you have an actual manual? If yes, any chance you can scan the transformer/rectifier schematic page?

Granny_ZeroCrossing.jpg

That's awesome! Good catch! I finally got to play a Granny on location recently for $0.25 a game. It was really awkward at first, but once i got the hang of it, it was a blast! The pinball was surprisingly snappy and fun to play. Good luck with yours!

pinballman3 hey man, just seeing if you got your g&g up and running. Just picked one up a few days ago. Down the street from ya here in Owensboro.
Ed