(Topic ID: 214063)

Help: Blackout won't boot (learn to logic probe!)

By OwenKhan

1 year ago

Topic Stats

  • 18 posts
  • 5 Pinsiders participating
  • Latest reply 1 year ago by someotherguy
  • Topic is favorited by 8 Pinsiders


Linked Games

#1 1 year ago

Situation report: Williams Blackout. LED's flash once on power up then stay off, however, game does not go into attract mode. I have seen it go into attract mode once, so I know it can work... when I press the test button it always gives me the 'lower LED stays on' error code, meaning there is a read write error on the 6810 RAM chips...

Completed work:
Replaced 40 pin interconnect
Replaced 6810 RAM and sockets
Replaced Roms
Replaced rom sockets (minus IC14 which looks good to me)
Replaced loose IC10 PIA chip slot on Driver board
Tested all voltages from PS to connectors on Driver and MPU boards (have not tested voltages after they get into the driver board or MPU (can't make heads or tails of the schematics, the other Bally machine I have has clear test points and values, Williams Sys4 MPU schematics don't seem to. Maybe I'm looking at the wrong one [Phoenix] maybe I just don't know what I'm looking at...)

Note to self: Self, check other sys 4 MPU schematics (as we don't know which game our board is actually from originally)

Weird stuff:
MPU board is system 4 (Black out is system 6). Previous owner says it worked fine for many years (besides issues with blowing SOL fuses...) so I'm not too worried about compatibility here and I read that sys 4 updated with a socket in IC14 is fine for running sys 6 games. However, there could still be a compatibility issue here...

A few sockets on MPU and Driver boards were replaced, but not by me. Continuity tests fine, but these are still on my list of things to check if all else fails.

So... I feel like I have given a decent try to bulletproofing the relevant weak points and nothing has gotten me into attract mode yet.
I have a Logic probe coming in the mail tomorrow and have been reading about what the heck to do with it... but I am sure I will need some help.

Questions so far:
Q1: how do I tell when I want the probe on 5v and when I want it on 12v, is it as simple as IDing the chip in question as TLL or CMOS? Are there any tricky spots to watch out for where there will be a 12v output on a 5v chip?

Q2: What the heck am I testing for?
Q3: And where do I start?

I think I want to make sure each IC is getting the power it wants (usually 5v on pin 1?) and that its ground is reading 'low' and pretty much all other legs should read a pulse (or match input to output)???

Am I basically looking at a data sheet for each IC in order to know what to expect from what leg?

Thanks guys, sorry I'm so clueless here... if anyone can point me to some relevant reading/video I'm glad to read up... Here is what I have been reading already:

and TerryB's logic probe guide: https://pinside.com/pinball/forum/topic/terrybs-guide-to-logic-probes

Reading through the examples on this home pinball repair link is making things start to make sense... but none of the examples are for troubleshooting boot issues, so they don't get in to IC stuff much. That is specifically the area I feel I need help understanding.

#2 1 year ago
Quoted from OwenKhan:

MPU board is system 4 (Black out is system 6)

This is what is really making me wonder???This can't be,Please keep the post short/simple,way too much at one time(Step by Step)

#3 1 year ago

Just confirmed, with another guy that he has a Blackout running on a Sys 4 board. Maybe mine isn't quite set up right, but it can work.

As for the length of the post, I made an effort to make it clear and concise and complete. If I post: black out not booting: LEDs flash once then go off. I'm going to get multiple people asking me for the info I have already included. Thanks for your opinion.

#4 1 year ago
Quoted from OwenKhan:

Just confirmed, with another guy that he has a Blackout running on a Sys 4 board. Maybe mine isn't quite set up right, but it can work.
As for the length of the post, I made an effort to make it clear and concise and complete. If I post: black out not booting: LEDs flash once then go off. I'm going to get multiple people asking me for the info I have already included. Thanks for your opinion.

If your game is calling for a System 6 board then that might be the answer to all your problems

Quoted from OwenKhan:

Thanks for your opinion.

Your welcome and "may the Wort's be with you"

#5 1 year ago
Quoted from OwenKhan:

Previous owner says it worked fine for many years

That's what they all say.

#6 1 year ago
Quoted from pinmike:

That's what they all say.

That and it is probably just a fuse.....

#7 1 year ago
Quoted from Robotworkshop:

That and it is probably just a fuse.....

Yup,The good ole fuse..Hehe!! or the kids have all gone to college..Lol!!!

#8 1 year ago

I don't recall if you posted the actual 5V supply voltage on the CPU and Driver boards. Easiest to measure across the 100uf filter cap (5V and ground are on either side of this cap).

Q1 - You are spot on - any TTL chips (which should be almost all of them on the CPU and Driver boards) you keep it on TTL. Setting it on CMOS and measuring TTL usually works fine but can give you erroneous pulsing readings.

Q2 - start at the pins on the CPU chip. You are looking for activity on the data and address pins. Lack of activity here means the CPU isn't running (could be clock, could be the CPU chip, could be program (ROMS)).
Then check that the blanking signal is going hi as it should.
Then check that the PIA input and output pins are pulsing. If the input pins are pulsing but the outputs are not, could point to a bad PIA (can also mean the program isn't running correctly).

And I second what the others have said and I suggested it in the other thread, just because the prior owner said it worked for years doesn't mean it really did. Maybe ask the person you found with a working Blackout with a system 4 board to send you closeup pictures of the CPU board. That way you can check the jumper settings. There are changes needed to the typical stock Sys 4 board to support the green flipper ROMs from a Blackout.

#9 1 year ago

Schwaggs, thanks again. I really can't express how helpful you are being here...

I asked the other guy with a blackout, he seems quite convinced that its not a compatibility issue and says sys 4 just works for blackout with no jumper mods. I think the only change needed from 4 to 6 is adding the IC14 Socket for the game rom.

5.00v exactly on both 100uf Caps (driver and MPU)

CPU pin test: I think I have 'activity' on all data and address pins... all of them give me both leds (which decodes as 'square wave'). Are the square wave readings a problem or is that normal? And I using the probe wrong?

Reading up on how to test blanking now...
And A quick search isn't turning up a pin out diagram for IC18 MC6820 PIA... any help on that? Edit: I guess its on the schematic, but I still don't know what the abbreviations mean...

IC18 PIA results:

pin1 vss Low
pin2 - pin9, PA0 - PA7 all Low
pin10 - pin17, PB0 - PB7 all Low
pin18 CB1 square wave
pin19 CB2 High
pin20 VCC High
pin21 R/W Square
22 CS0 Square
23 CS2 Square
24 CS1 Square
25 E (?) Square
26-33 D7 - D0 Square
34 RESET High
35 RS1 Square wave
36 RS2 Square wave
37 IRQb High
38 IRQa High
39 CA2 High
40 CA1 Low

Ok, so inputs (D7-D0) are all pulsing. But the outputs (PA and PB lines)are all low. So my PIA might be bad, or not running right for some other reason?

Would pulses getting to the PIA but not getting past the PIA be the case if the game ROM wasn't running right? I can try replacing that ROM socket now...

#10 1 year ago

Here is a copy of the 6821 PIA data sheet. https://www.jameco.com/Jameco/Products/ProdDS/43596MOT.pdf

Well, that's a good sign. I don't know how to tell if the board is running correctly or the PIA is bad. If it is already socketed, not a bad idea to try replacing it.

Did you test the outputs of the other PIAs?

What about the blanking signal? You can find it on pin 37 of the 40 pin connector (and other places).

#11 1 year ago

Another helpful guy on Facebood helped me do some logic probe testing and I may have the wrong version of the game Rom. I bought my replacement before I understood there was a difference between the original and the replacement that consolidates a few of the other chips. That could cause the behavior I'm seeing, right?

Looking into that now...

Haven't tested the other PIA outs... I can't imagine they are doing much as I'm pretty sure the Game Rom isn't running. With my old chip (including some busted legs) the game plays a random sound on power up, with the new Game Rom chip it never plays any sound. That make me think the new chip isn't right...

#12 1 year ago

Yep, that was it. Wrong ROM. Note to self: only change one thing at a time...

I jury rigged my old busted leg ROM and jumped the bad legs... ugly as sin, but it confirmed my problem. Now I can order the right rom and start troubleshooting playfield stuff while its on the way.

Thanks so much Schwaggs

#13 1 year ago

Awesome! Congrats on figuring it out!

#14 1 year ago

Thanks Schwaggs, now its on to fixing mechanical stuff... one more question on the rom...

Are there actually two versions of the game Rom? Or did Blackout never use the other ICs mentioned below?

This link is what I'm reading:

And the part in question:
System 4/6/7 CPU Board ROM Upgrade.
Most System 4, System6 and System7 CPU boards uses five ROM sockets: IC22, IC21, IC20, IC17 (from left to right), and sometimes IC26 (mounted above IC22). There is a sixth ROM socket at IC14 too. Again, just like in System3 CPU boards, IC14 can use a 2716 EPROM, which will eliminate the 3624 masked ROMs (512 bytes) at IC22, IC21 and also IC26! But in the case of System 4/6/7 CPU boards, the modification of IC15 discussed above is already done.

Again, since we have already discussed replacing all the CPU sockets, this trick will allow us to replace fewer sockets on a System 4/6/7 CPU boards too. That is, using a 2716 (2048 byte) game EPROM at IC14 will replace the *three* 3624 masked game ROMs (512 bytes each) at IC22,IC21,IC26. Doing this means the sockets at IC22,IC21,IC26 will not be used, and do *not* need to be replaced!

Since the chip selection circuit is already set to use IC14, it is just a matter of getting a new EPROM "burned" to replace IC22,IC21,IC26. There are lots of people that offer this service for around $10 to $15 for this chip. Williams' web site also has the binary ROM images for these EPROMs available for free.

So am I safe to assume that any EPROM image that is 2048 bytes is the one I'm looking for? I found 5 different downloards and they are all that size... thinking there may only be one, in which case my new game ROM is just bad.

#15 1 year ago

My Blackout has three 2k 2716 (2048 byte) chips for the code. Two are the flipper ROM chips and one the game specific code. There was a patch to one of the flipper rom chips to divide the score by 10 so it is less likely to roll over. I'd use the three 2716 chips.

#16 1 year ago

Anyone know a place I can get the divide by 10 flipper rom? I haven't been able to find it, either for sale or just an image to burn...

#17 1 year ago

I think I have a spare. It would be on a 2716 chip.

#18 1 year ago
Quoted from OwenKhan:

Anyone know a place I can get the divide by 10 flipper rom? I haven't been able to find it, either for sale or just an image to burn...

It's on IPDB..


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