Reference:

http://pinball.flippers.info/system6mpu.pdf

74LS139 getting cooked.

This is a BlackOut game, with the MPU looking like it's had some work in the past (sockets, excess resin, cuts on the solder side from some sloppy solders I've cleared up). I've cleanly resocketed and resoldered this chip, in the "Address decoder" region of the MPU on this Williams System 6 MPU for the game BlackOut. The jumper J3 is wired with a 0 Ohm resistor, J3 is not connected. Looks like a pin is bridged on the solder side (connected in the data buss section in D4-D8 on pins 12 and 14 on chip ECG6889/P 312 185617KK) and the solder side pin 16's solder pad is gone. Does not look like any traces were connected to it.

Overall the board is not bad after I pulled off the old solder, reflowed new 60/40 rosin core solder on the main interconnect and anything else I saw that was off.

I would like some direction from those more knowledgable than I to narrow down the search. Thanks in advance.

The address decoder IC - snip from the System 6 MPU assembly diagram (from the link above) - it's IC 15 by that diagram.

When I say getting cooked - meaning it's very hot to the touch, system won't boot. No other ICs or parts on the MPU are hot, on the MPU itself two red diag lights won't clear, diag button does nothing, switch DS1 has all positions off. I'll take parts pictures and post them here also. Thanks for the pro-tip!

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Oh, I realize I mistyped my first post. J3 is connected to a zero ohm resistor, and J4 is connected to nothing.

I think I'm onto something - pulled chip out, measured what I believed to be a short, measured socket, replaced with new chip.

Game starts but errors out - top left display reads code "1495 1" and bottom left display reads code "04 00".

I'm going to look for this code online and thank you all.

Two of the legs on the 74LS139 was slightly bent under - enough I couldn't see it without pulling the chip and examining it closely.

It's been a lot of work getting to this point, glad I'm seeing the light.

Yes, did that - put in batteries and now it's 'stuck' with all displays showing full 0's, with the top left display alternating 600000/000000. Looking on PinWiki etc...

The game does seem to work properly when in "Master Command" mode and when testing either in manual or auto-step mode.

I was able to get into the settings mode and it looked like it was working, allowing me to page through settings and whatnot, much like my BK does.

Just can't get past this 600000/000000 'thing' it's on. I'm not sure what it's doing.

Thanks for that - I'll look into that 2.5SB fuse for the coils as well.

Yes, thanks - I've done the bulletproofing on the power supply and the rectifiers.

stangbat

Something screwy keeps happening - I'm blowing the 2.5A SB fuse for the coils. Checking each, flippers read 1.2 ohms when not energized. Most all of the other coils - kickouts and drop targets - read 4.3 ohms. The one drop target at the top of the board reads 3.8 ohms. I've checked and triple checked.

Anyone have any tips (have looked closely for broken wires, but saw none)...?

Gotcha, thanks for the tips! Much to read, having direction is very helpful.

https://pinside.com/pinball/forum/topic/blackout-wms-system-6-keeps-blowing-25a-sb-fuse-f2#post-4452934

Related to this post ^ - I think I have it fixed with all the help!