Roadshow switch issue - Resolved

[Zero_Hour]

Well, I received a Roadshow yesterday, and it is in immaculate shape. Best play field I've ever seen on one in person, and the Red and Ted heads and Bulldozer blade are all unblemished as well, so I'm pretty happy with the purchase. The machine does have an issue, and hoping for any insight into troubleshooting it.

When running a test at startup, the machine says that switches 31-35 need to be checked. When I go into the Switch Edge Test, they are indeed all unresponsive, as are switches 36-38, so an entire column of the switch matrix seems to be out.

My question is where is the best place to start trying to remedy this?
I've rebuilt flippers and pop bumprs, and even replaced a few blown capacitors on my AFM, so I'm not afraid of working on the Roadshow, but this is new territory for me, and I'd like to attack the problem in the most logical way possible.

[smartbomb2084]

Check the Switch Matrix connectors at the bottom of the CPU Board (J207 Pin 3-Green and Orange wire) for hacks or battery corrosion...Look Closely...

Next...check U20 (Pin 16) on the CPU...

[Zero_Hour]

Thanks for the response.

Checked the J207 connectors. Wires look good to the connector, no broken pins on the board, no corrosion to be found, board looks to be clean of any soldering hacks.
U20 on the CPU is a socketed IC. Chip was seated, no corrosion, signs of damage to the chip or the board.

[smartbomb2084]

When you put the game in SWITCH EDGES Test are all of the Column 3 switches stuck CLOSED or are they OPEN and unresponsive?

If stuck CLOSED... remove Connectores J207 and J209 from the CPU and see if the Column goes out while in SWITCH EDGES Test.

If OPEN... check for a break in the Green-Orange wire  (J207 Pin 3)  to the switches in the column.

Use a DMM not just your eyes...

[ChadTower]

Definitely use the DMM and not your eyes.

[Zero_Hour]

Looks like I will be putting that DMM to use. Might be a day or two till I have a chance to get to it, I'll let you know what I find.

If you knew how bad my eyesight is, you'd know how funny I'm finding the "Don't use your eyes comments."

[Zero_Hour]

OK THEN...

I literally had not touched the pin since I last posted. Turned it on, and decided just for the hell of it to run the SWITCH EDGE TEST again.

The good news: The switches in Column three are now responsive.
The bad news: The response is that when I close switch 3X in the test mode, the entire Row X lights up as closed, and I get the GND. SHORT ROW X message in the test.

 

[smartbomb2084]

Don't know what you mean by switch 3X...

Whichever switch that is it  needs to be physically checked to see if it is shorting on something under the playfield.  Check at all the switches in the column for underplayfield shorts.

You can test U20 on the CPU with your meter too.

With the game off.. put your DMM on the 'Diode' setting and put the POSITIVE (Yes POSITIVE) meter lead on Ground and with the NEGATIVE Lead probe pins 11-18 of U20.

They should all read approximately the same...about 790 on my meter.  Pay close attention to pin 16, this is Switch Column 3 and if bad will read significantly different than the others.

Check the EDDY Board of switch 37 ( Hit Red) too. Disonnect it with the power off and see if it changes anything.

[Zero_Hour]

Thanks for the info on how to test U20. I'll check the EDDY board as well.

What I meant by 3X / row X is: when I test switch 31, row 1 lights up, switch 32, row 2, etc ... For the entire colum. Sorry if that wasn't clear.

Hopefully my son will take a long nap this afternoon, and I'll have a chance to put the meter to work.

[Zero_Hour]

BINGO. Pins on U20 are reading  around 580 on my meter, pin 16 reading 27.

Hopefully replacing that IC fixes the problem.

[smartbomb2084]

Cool.. Glad to hear it...

You aren't completely home yet though... SOMETHING caused U20 to die..

You still need to physically check all the switches in that column for shorts... This time DO use your eyes...

And... THANKS FOR POSTING BACK YOUR RESULTS!!!

We can't learn if we don't know the outcome of our attempts to fix things.

 

[Zero_Hour]

Roger that on checking all the switches for shorts. I'll have some time before the new IC gets here, so no excuses for not doing it.

I'll let you know how everything goes once the new chip is in. And i'll get some pics of the machine up as well, because NEW (old) PIN!

[ChadTower]

IMO Roadshow is a very underrated game.  It's very similar to Twilight Zone and yet half the market price.  I've never quite understood that.  If you look at the two playfields side by side they are almost mirror images right to left.

[Zero_Hour]

Completely agree with it being an underrated title - though I don't know for how much longer. I look at it as kind of a "Pat Lawlor's Greatest Hits", as it has a lot of his best known design elements in once machine. Lately I've been seeing them for close to, or over 4k, Though I guess a lot of that is just average creep in pin prices over the last few years. I found this one for 2800, and decided to pull the trigger.
It's another title that my wife and I played a lot back in the day, so I knew it would be a well received addition. I get to tick off Widebody and Pat Lawlor design off my pinball checklist.
It'll be a while before I'm ready to add another one to my collection, but I'm pretty sure it will be an 80's vintage when I do.
The only real gripe I have with this Roadshow is that the backbox was redone with LED's and they are a mix of Red Green Blue and Yellows that really look like crap, especially in low light. At least that's an easy fix.

[Zero_Hour]

Was able to check the switches over the weekend, and couldn't find any shorts in the affected column's switches.

The replacement chip for U20 arrived today, and thanks to U20 being socketed on WPC-S boards, I was able to replace it in short order. Everything tests, and works as it should.

I'll try and get some pics up later tonight.

 

[smartbomb2084]

I have been here several times before with U20.

So far so good... We still haven't officially determined the cause of U20's failure...

Hopefully, before you got the game,  some TOOL was adjusting things with the power on and caused some kind of temporary short...blowing U20.

Since you did not find anything wrong with the Column switches themselves ...we may be good...

If U20 dies again after an extended time of play then CPU U23 is bad too...

U23 is hard to check accurately without removing it from the board....

I am keeping my fingers crossed and praying to the Pinball Gods for you...Good Luck.

 

[spoot]

Woot!  Time to wreck some roads!