Hi guys,

I've got a mistreated RoadShow pinball, it really needs lots of love and time, and Im doing my best.

I've checked and repaired all the connectors on backbox boards and playfield boards (optos) and that solved many problems.

Now Im stuck with a matrix problem, all 10s and 20s switches are not responding but the wiring is OK.

I've found an old ULN2803 drop inside the backbox so I suppose they tried to solve that problem changing the U20.

Following your nice forum and the Williams repair guide and did many test, and PUT A NEW ULN2803 on the U20 socket today.

Switch Level Tests
===========

Before the new U20 the test said, ROW 1 GND SHORT and the ROW 3 and 4 did not respond, pressing START also says GND SHORT.

After the new U20, the test says that I have no more GND SHORTS, but switches from 10 to 30 did not respond 31 to 80s are OK, pressing START does nothing, not response at the Matrix.

WIRE JUMPER TEST
============

Disconnected J212, J206, J208, J207, J209, only left J205 (coindoor test buttons) connected at matrix side of the CPU board, so no coneection with the playfield.

Connected a wire to PIN 1 at J209 and at the other side of the wire Im using a diode.
With the diode I touch all the pins on the J207 on by one and check at the Switch Levels screen:

PIN 1 and PIN 2 do nothing, the rest of PINS register a good closed switch signal, 31,41,51,61,71,81.

Just for fun I did the reverse test, connected the wire to PIN 1 at J207 and with the other side of the cable and the diode (switched diode side), I touch all the pins at J209 one by one, 0 response, I suppose that this is logical but I have to try

Sooooo, guys, what should I do next???

COLUM_TEST (resized).jpg

Thank you very much for the advice Homepin, I'm trying to find the CPU schematic, but in my manual is only the assembly, I cant find a LM339 on the CPU board, only 74LS, 74HC...

Yeeahh man you are correct, on the chips says BA10339 and its the same IC , still trying to find the schema too see to what IC goes PIN 1 and PIN 2

Hi Zaza thanks for the schema, sadly I only have a DMM at hand, I hope the U23 is not fried cos I dont have a replacement for it

Nope, my DMM is some years old and dont have that option.

After more reading, some people says that I have to change the U18 (LM339) that controls ROWS 1,2,3,4, others says that sometimes the U20 dies killing the U14 (74LS374).

What do you think should be the first step? I have replacements and sockets for both types of CIs

Hi Homepin,

I've been trying many different things, yes, you are right, doing random is not a good idea but I have no patience hahahahaha.

I will try to fix it this weekend, and if I cant find the problem send it for repair, but I love to fix my own pinballs and scratch my head time to time

I have carefully removed the U14 ICs cos it looks a little burnt (grey line of paint was partilly falling off), installed a socket, verified continuity on all the pins to the board traces and put a new IC on the socket..... no luck.

Now I don't get the switch errors on BOOT, just factory reset blah blah, time and date blah blah, then I enter on SWITCH TEST and everything looks fine, BUT, big BUT:

On the coin door, all buttons works but "DOWN", I can use SCAPE, ENTER, UP, but no DOWN.

Last update, I was doing some switch test and pinball did something like a reboot and shows me "U22 ERROR".

I dindt touch the SEC CHIP, all the traces are ok... but I see that the pins of the U22 socket may have developed cold solder problems, looks brown and has some cracks, Im going to check it

Well some improvement, now all the correct leds show up on the boards, no more reboots, still no "DOWN" button, and U22 ERROR if I boot with the batteries intalled :/

During boot process the screen dont show the correct U22 code or serial number, only TEST blah blah and "0000000" instead of the SN.

Then "U22 ERROR" and the field runs on attract mode.

I just cleaned it to work on the ICs and the board is in nice shape, only found a scratch on 3 traces on the back of the board and corrected it cos the traces are very small and were too close and they have a short, now traces are ok.

Well... U13, U14 and U20 are new, still "U22 ERROR" at boot.

I already fixed 3 damaged traces, so I think the problem is going to be related to a broken trace somewhere.

Did you know were can I get the WPC-S schematics?

Thanks in advance

Thanks!!

Im not sure if the U22 is broken, I don't think so cos it was working great before I changed the U14 (another user here had the same same problem).

Maybe my U14 was broken and now is working but the problem is at another IC that interacts with the U22, maybe the U22 is not doing a good connection on a leg, or there is a broken trace somewhere and it is not detected correctly.

Im going to put the CPU board at the pinball without the U22 chip installed and see if I get the same U22 ERROR

My eyes hurt but I made some progress here:

From U14 pin 14 (D6), list of destination ICs pins following the schemas and results:

U11 PIN 14 (FAIL)
U4 PIN 25 (FAIL)
U6 PIN 20 (FAIL)
U8 PIN 18 (FAIL)
U12 PIN 13 (FAIL)
U7 PIN 13 (FAIL)
U25 PIN 20 (FAIL)
U24 PIN 15 (CORRECT)
U15 PIN 14 (CORRECT)

So, I hope, here is the problem with the U22 Error after installing the new U14, Im going to sleep (5 in the morning here), and tomorrow MORE love this machines

I can't go to bed hahahahaha 6:50 in the morning and still solving issues here.

U14 100% perfect now, found and fixed damaged traces and that pointed my attention to U15.

U15 is now the problem, the PIN #16, that pin is supossed to go to:

U24, U14, U11, U3, U4, U6

And goes to NOTHING AT ALL.

Using light and a magnifier Im trying to find the broken trace that PIN16 uses, but the problem is that I cant see any trace going to PIN16 :O

Don't know if the schematic is wrong, maybe I dont have an update version.....

U15-PIN16 (resized).jpg

Great vídeo, thx man!

Similar problem, but my board has many more problems

I have to find what is going on with pin 16, can it be an unused pin and manual is outdated???

Well, verified the schema is for my board, as it says A-17651-XXXX and my board is a 5764-13869-04 (A-17651).

Im still unable to find where the hell the pin #16 connects to the traces that go to U24, U14, U11, U3, U4, U6, so Im going to desolder the chip to check the traces under it, and put a socket and a new IC...

THANKS MAN!!!! you know what.... U22 PROBLEM SOLVED!!!

Now game boots but I've got lots of shorted rows, only 2 and 6 are free rest are shorted (no connectors on the board)

************
...................
************
************
************
...................
************
************

I think there is a IC fried somewhere that controls those rows.

I've replaced U20, U13 and U14.

PD: sorry for the "these, those, that" mistakes, I'm not the best at english grammar hahahhaha

I have the U13 connections already verified, in fact I did:

U13 = all correct (new IC)
U14 = all correct (new IC)
U15 = all correct
U20 = all correct (new IC)
U23 = all correct
U24 = all correct

As I understand, U19 and U18 are responsible from the rows, so Im suspicious about them.

I had to put 4 wires behind the board to fix it, I'm sure I damaged one little track while working on the IC, the other broken tracks came from scratches behind the board, bad manipulation or may be the board was inside a box with many other boards and then they put it on the pinball

Well, I just put new 18 and 19 ICs on the board, now the test menu works normally (does not hang anymore) but still many shorted rows.

I'm running out of ICs to check hahahahah.

so my report is:

TRACES AND ICS

U13 = all correct (new IC)
U14 = all correct (new IC)
U15 = all correct
U20 = all correct (new IC)
U23 = all correct
U24 = all correct
U18 = all correct (new IC)
U19 = all correct (new IC)

Thanks for your help, slowly, but the board is coming back to life

I did it, I have the RoadShow working and ready to start the playfield and cabinet restoration

I would like to thank you all for your help and guide.

The board has suffered a lot before I got it, now its clean and fixed.

Some broken tracks and many ICs were damaged, so every time I change an IC a new error showed, ahh I forgot, I put new U23 and U24 ICS, both were bad

. New U20 ULN2803
. New U13 into socket
. New U14 into socket
. New U15 into socket
. New U23 into socket
. New U24 into socket

. Lastest GAME ROM installed

Again thank you all