(Topic ID: 258666)

Judge Dredd won't boot


By antinea

3 months ago



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  • 25 posts
  • 7 Pinsiders participating
  • Latest reply 43 days ago by bssbllr
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#1 3 months ago

After desoldering the ram in U8 to install an anyPin DMD+, my machine refuses to boot anymore.
At first, the blanking and +5VDC led remained lit, and there was one "bong"; the screen remained empty.
After unplugging and plugging again connectors, now only the +5VDC led is lit, I still hear one "bong", and the screen is scrambled.

Did I just mess up the soldering/desoldering? If that was the case, the game would still boot and the Diagnostics led would inform me that there's a ram problem. So uh... I'm at a loss here.

My only clue, after looking it up, is that W3 is in and R93 is out, which means the ram was 62256; I definitely didn't check that when I soldered the anyPin DMD+. Could that be the problem? (once again, if that was the case, I suppose the game would actually boot and inform me about a ram problem)

Thanks if anyone can help me out

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#2 3 months ago

Did you try reseating the ribbon cables?

#3 3 months ago
Quoted from pinmike:

Did you try reseating the ribbon cables?

Going along with that, make sure they aren't off by one row.

And yes, you'll have to configure the jumpers for 6264 RAM.

https://www.pinwiki.com/wiki/index.php?title=Williams_WPC#Jumpers.2C_RAM_and_ROM_size

#4 3 months ago

If you damage the pads, traces or through holes while working on U8 it's more than likely the board will not start correctly. Check all the pin connections / continuity between the 28 pins of U8 both upstream and downstream. A break in the address or data bus will result in the board not starting correctly.

The software performs some form of diagnostic check. The problem is that if the address or data bus are not correctly wired then the diagnostic check cannot pass to even display anything. The first sign of any successful pass of the diagnostics is the blinking diagnostic LED. If you don't get that then everything else beyond that does not matter. The display is scrambled because there's no software programming the display output (it's just displaying whatever the power-on RAM state is). The "bong" happens entirely on the sound board and is not under CPU control.

#5 3 months ago

Thanks for the replies! I checked the ribbon cables a couple of times before posting the first message, so unless I'm really sloppy (could be!), that part should be ok.

Before I do anything stupid, would it be a good idea to desolder the ram, wait a few days for a socket to be delivered, and then do the job again? I mean, it should be easier and cleaner with a socket...

Also, since it'll be another week to get the resistor to switch to 6264, can it damage the ram/board if I power it with a 62256 configuration? I realize it might be a really stupid question, but I'm pretty clueless when it comes to electronics.

#6 3 months ago
Quoted from antinea:

I checked the ribbon cables a couple of times before posting the first message, so unless I'm really sloppy (could be!), that part should be ok.

It's usually best to check from different angles. sometimes if you're just looking at it from one side of the cabinet, you might not be able to see that it's off by one row in favor of the side you're on.

Quoted from antinea:

Before I do anything stupid, would it be a good idea to desolder the ram, wait a few days for a socket to be delivered, and then do the job again? I mean, it should be easier and cleaner with a socket...

Whenever you replace a chip, it's always good practice to use a socket. If you fiddle too much with the pads/traces, they are likely to be damaged by the repeated soldering/desoldering.

Quoted from antinea:

Also, since it'll be another week to get the resistor to switch to 6264, can it damage the ram/board if I power it with a 62256 configuration?

Personally, I wouldn't leave the game on the way it is. I don't know if it will damage the NVRAM or not, but I'd rather not chance it if it were my game.

#7 3 months ago
Quoted from antinea:

Before I do anything stupid, would it be a good idea to desolder the ram, wait a few days for a socket to be delivered, and then do the job again? I mean, it should be easier and cleaner with a socket...

Also, since it'll be another week to get the resistor to switch to 6264, can it damage the ram/board if I power it with a 62256 configuration? I realize it might be a really stupid question, but I'm pretty clueless when it comes to electronics.

Best to start with configuring the board first for 6264 and be sure the game boots and plays before you try and remove the NVRAM, if you really want to add an IC socket. At least this way you know it started off working before adding the IC socket if something were to happen. At that time, then you know you would be dealing with a damaged pad/trace.

Personally, I would just leave it soldered in at this point, even after the board works with the 6264 configuration. It is rare NVRAM fails.

You can unplug J114, which is 5v and 12v out from the driver board to the other boards. Why would you want to power the game on when it does not boot?

#8 89 days ago
Quoted from PinballManiac40:

Why would you want to power the game on when it does not boot?

Out of curiosity, I guess.

Anyway, I'll configure the board first, and then try to work my way from there.

#9 85 days ago

Allright, time for the bad news: I configured the board for a 6264, and nothing changed, it still won't boot.

Since I guess it's going to be a nightmare, I took out the nvram; I'll install it later with a socket when the board actually boots (I long for the ram error led code, it'll be the end of the tunnel).

It's now time for the 100$ question: what do I do? You advised me to test continuity; my multimeter is ready but what exactly should I test?

#10 85 days ago
Quoted from antinea:

I took out the nvram

Time to take a picture of the top side of the board so you can zoom up to look for damaged traces/pads before installing the IC socket.

#11 85 days ago

Here we go. I don't really see how I could have damaged the traces under the ram, but it's a bit scratched nonetheless. Anything that screams DAMAGE to you? If so, what should I do to test/repair it?

On a side note, what's with that wire that's soldered to U1?

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#12 83 days ago
Quoted from antinea:

On a side note, what's with that wire that's soldered to U1?

That’s a jumper wire from a bad trace.

#13 83 days ago
Quoted from antinea:

what do I do? You advised me to test continuity; my multimeter is ready but what exactly should I test?

http://arcarc.xmission.com/Pinball/PDF%20Pinball%20Misc/Williams%20WPC%20Schematic%20manual.pdf

Here is the schematics May not be perfect but I would follow u8 lines as best as possible for continuity. Check the schematics and due some testing you will be able to find bad trace if there is one. I had to do this and was able to find on my dh

#14 83 days ago

Thanks for the help!
...I'm sorry to be absolutely helpless, but I know so little about electronics and schematics that I still no idea what to do because I have no idea what I'm looking at. As far as I understand, I should put one end on a ram pad and the other on the next solder going from that pad for testing... but then some traces are on the top side, and I can't follow them because they go under other chips and I have no idea where they end up. I suppose that's where the schematics come in handy, but I don't understand them
Sorry for making you all waste so much time on my lack of basic pinball knowledge/skill, being so dumbstruck really ain't fun

#15 83 days ago

I'm not seeing any damage on the top side of the board. Can you post a picture of the backside?

#16 83 days ago

On the schematics one of the first pages is epic board here is pic and on that page is u8 so try and follow where the d’s go to and from And the a’s they all head to other chips. I just do my best eventually you will find something from the norm
If the trace is broke

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#17 77 days ago

It took way too long, but I finally tested the continuity for U8, and I don't really seem anything strange; I mean, at least all pins lead to somewhere, provided I didn't mess up the measuring.

Since I have no idea how the pins are numbered, I made up my order. And then I made a spreadsheet. Does anything strike you?

On a side note, there was indeed one damaged pad, but not what I expected: U8 goes to W3 and then R93. The damaged pad was on W3 (I'm not sure how to repair this, so I just made a simple jumper cable from W3 to R93, following the trace. Yet I suppose it has nothing to do with the problem, since I most likely damaged it when removing W3, which I did way after the game wasn't booting.

edit: I'll post a picture of the backside when I get home.
jd pins 2 (resized).pngjd continuity (resized).png

#18 76 days ago

As requested, here's the backside. I only worked on U8 and W3/R93, so I'm still really confused about this problem.

20200116_185924 (resized).jpg
4 weeks later
#19 47 days ago

I hate to do this, but I'm bumping the thread, since it's been nearly a month. I feel like it's something workable, but I fail to see the issue.
If we can't find what's wrong, I'll eventually send it to repair, but...

#20 47 days ago

The pin numbering system you used is not consistent with standard order. It's really hard for people used to standard order to see what's wrong. Reverse your 1-14 and 1-16 order and try using the information below.

The address bus stretches from the ASIC to the I/O connector through the main CPU ICs (U4/U6/U8/U9).

The data bus stretches across the board with the address bus but also connects down through the buffers and flip-flop (U7/U11/U12/U13/U14/U15).

bus_address_00_07.jpgbus_address_08_15.jpgbus_data_00_07.jpgu8.jpg
#21 44 days ago

Thanks a lot! The pictures and the spreadsheet were incredibly helpful. Now I know standard pin numbering order, too.

I tested continuity for everything on your spreadsheet. I've only encountered one issue: U08-12 doesn't beep with U03-17. Yet on the one hand, U08-12 beeps with U09-32, U11-07, U15-07, and U07-06; on the other hand, U03-17 beeps with U04-30.
Now, please bear with me on this one, because it might be the issue or something incredibly stupid from me: when I put the COM end of the multimeter on U08-12, and the other end on U03-17, it doesn't beep but I have some reading (something between 960 and 980), but when I reverse the two ends, I get absolutely no reading. Out of curiosity, I tried reversing the ends of my multimeter to check everything else, and the continuity is still perfect. Could it be the problem?

I still have a couple of questions: what's VBATT exactly? Also, U08-21, 23, 24 and 25 on the spreadsheet are listed in #3 to U08. I guess that's a typo.

I'll double check all the continuity on your 3 pictures tomorrow, since I'll have some more free time, at last!

#22 44 days ago

It looks like D1 is missing continuity somewhere between U4 and U8.
Seen by the PCB, I would go for a damaged trace close to U8-12.

Measure continuity between U4-30 and U6-14. Then between U6-14 and U8-12

Left side = component side of PCB.
Right side= your PCB solder-side + components location

#23 43 days ago
Quoted from antinea:

I've only encountered one issue: U08-12 doesn't beep with U03-17. Yet on the one hand, U08-12 beeps with U09-32, U11-07, U15-07, and U07-06; on the other hand, U03-17 beeps with U04-30.

It sounds to me that you've pulled the through hole at U08-12. This is where the D1 signal goes from the bottom of the board to the top of the board. The connection with U09-32 is at the bottom of the board (but goes back to the top through the via). I agree with what zaza wrote. You need to verify where the continuity is broken between the connections going "up" from U8. If there's no continuity between U08-12 and U06-14 then you can probably put a jumper wire between the pins and test that the board boots. See picture for better detail. It's the yellow/red signal.

Continuity is continuity. For my DMM it appears to be defined as less than 50 Ohms resistance. I typically don't diode test between pins. I only check for continuity to make sure that digital signals are correct.

Quoted from antinea:

I still have a couple of questions: what's VBATT exactly?

VBATT is the voltage source for the battery backup for the SRAM. It's labeled on the schematic. It can be selected as deriving from the battery (B1/B2/B3) or the power source (VCC) through W6 or W7.

Quoted from antinea:

Also, U08-21, 23, 24 and 25 on the spreadsheet are listed in #3 to U08. I guess that's a typo.

Thanks. That's a copy/paste error from the U06 entry. I've fixed it. See picture for correction.

u8_corrections.jpgu8_traces.png
#24 43 days ago

Allright!
There was indeed a continuity issue between U6-14 and U8-12 (as I mentionned earlier, a reading but no beep, and it wouldn't work if I switched the tips... that's pretty mystic to me). So I put a jumper between those and boom, it's working again!

20200218_145306 (resized).jpg

Thanks a lot to everyone for their help, without you I was on the verge of giving up!

Out of curiosity, and because it's been invaluably helpful, where did you guys get those schematics/picture hybrids?

#25 43 days ago

Zaza’s the man.

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