Williams test bench... Williams Collector/Repair Thread!

[Thomas]

Williams test bench... Williams Collector/Repair Thread!

I have bought so much Williams stuff lately that its time to start learning how to fix all my own boards for my private collection.

I was wondering what tools all you Williams guys here use to test with and repair.

So I will kick off this thread with what docs I know of. Please add to the document list!

http://www.robotron-2084.co.uk/
http://arcarc.xmission.com/PDF_Arcade_Williams/

Please add what you can to the thread with links to build/buy the tools and parts needed.

I hope this thread will turn out to be an awesome bookmark of knowledge for all the Williams collectors.

 

[Dokert]

Not very practical for the average Williams owner, a test rig is a valuable tool.

 

[Thomas]

Thanks Dokert, That test rig is on my list...
Is that a factory harness, jamma or is that one of the new ones?

So a few cheap tools on ebay. I will link up some more tonight.
I wish I could find a better logic probe that is affordable.

All ebay links
-----
Logic probe Lp-560 22.00 shipped http://tiny.cc/5lZpA
Digital Multimeter Centec 12.00 http://tiny.cc/xSzl0
Eprom programmer search http://tiny.cc/YfT95

Not sure which burner you guys like the best maybe
some of you could chime in. I know all this stuff
is cheap junk. So please provide something better.


Extra info in case you have never read Sean's page

http://members.cox.net/seanriddle/willy.html
http://members.cox.net/seanriddle/willrom.html

 

[YellowDog]

Eprom programmer search http://tiny.cc/YfT95

Not sure which burner you guys like the best maybe
some of you could chime in. I know all this stuff
is cheap junk. So please provide something better.

I have a BP Microsystems 1140. There are currently 3 on EPay ranging from $9.95 to $100 (search bp microsystems). It will burn everything I have tried, except some oddball 2716s. I think I just need to tweek the voltage on those to get them going. I just haven't had time to play with them enough.

The most important thing with Williams boards is to get a reference set that works. Then you can swap parts in one at a time to build up a collection of known good parts.

Also, not considered a "test tool" but indespensible nevertheless, get one of the lablemakers that print on the paper tape (Dymo or Brother). Use this liberally on the boards labelling good boards, bad boards & their symptoms, little boxes of parts, ziplog bags of parts, EPROM labels, etc. Organization is a must. Or you will spend days trying to bring up a system from dead parts because you were "sure" this CPU board worked.

ken

 

[Scucci]

That's the address I was trying to think of... arcarc. Too bad, they don't have a Galaga troubleshooting guide. Oh well.

Anywho, I love the Recaps in the Williams section. I've been using those to fix my Defender... actually, I have some parts that should be getting here in the next few minutes that I'm hoping will get the boards back up and going. Anyways, yeah... the flowcharts in those Recap pdfs are great... I just wish some of our friendly local know-it-alls would get together and put something like that out for other boards.

 

[mspaeth]

Easiest to make a JAMMA adapter, and make a JAMMA test bench, than make multiple test benches for different boardsets...

 

[Peale]

Easiest to make a JAMMA adapter, and make a JAMMA test bench, than make multiple test benches for different boardsets...

I agree, but Williams boardsets are a bit different, if only because they spread the different functions over many different boards.

I'm curious to see what you have for this actually, Mark; your gizmos are always top notch.

 

[Dokert]

Thanks Dokert, That test rig is on my list...
Is that a factory harness, jamma or is that one of the new ones?

Shown in the picture is 4/5 of a new harness. A stock harness also will work fine. A jamma harness can be used too. It really doesn't matter for a test rig.

I use a stock power brick modified with an on/off switch and the safety interlock switch removed from the circuit as it is not needed. This provides my iso, and power for the test monitor. It also allows me the flexability to test Williams power bricks too.

Everything is removable, and modular so to speak.

 

[mspaeth]

I agree, but Williams boardsets are a bit different, if only because they spread the different functions over many different boards.

I'm curious to see what you have for this actually, Mark; your gizmos are always top notch.

I keep a working williams set w/ jamma adapter around to swap unknown boards in on... staring with a dead rom/cpu board pretty much sucks... It's much nicer to start with at least 1/2 working.

I never throw the widget board on until the end... it doesn't need to be there for the board to function, but it can mess things up.

 

[YellowDog]

My test rig is similar to Dave's, except that I have a couple of the metal mounting plates (the one for CPU, I/O and ROM and the other for Sound and Power Supply & Heat Sink). On my power block I kept the interlock switch and the marquee and monitor power cables (basically it is a stock Williams power harness) so I can test fluorescents and monitors as well as the boards. For space puposes, I build a black box that has coin door functions so I can step through the diagnostics as well as coin the game up. For a while I had an old Robotron CP that I could plug in, but that got old (Joust flapping on a joystick is a serious pain). So I will be making adapters to map my JAMMA lapboard controls to specific Williams games.

For JAMMA, my test harness is being rebuilt. I have a lapboard that I am rewiring with P1 & P2 joysticks and B1-B4 for each player. The card box will have the power supply, JAMMA card edge connector and room to bolt a monitor on top. I'm still working the details out for that.

I just need to hit the lottery, 'cause I got more projects than time right now.

ken

 

[saltbreez]

Tektronics 454 or 454A

I have bought so much Williams stuff lately that its time to start learning how to fix all my own boards for my private collection.

I was wondering what tools all you Williams guys here use to test with and repair.

So I will kick off this thread with what docs I know of. Please add to the document list!

http://www.robotron-2084.co.uk/
http://arcarc.xmission.com/PDF_Arcade_Williams/

Please add what you can to the thread with links to build/buy the tools and parts needed.

I hope this thread will turn out to be an awesome bookmark of knowledge for all the Williams collectors.

Get a Tektronics 454 or 454A O-scope. You can find a working one on epay for $100 if you are patient. Get a few of the cheap Chinese 100MHz probes. The O-scope tells you a lot more than the logic probe.

 

[jrok]

Not very practical for the average Williams owner, a test rig is a valuable tool.

That looks scarily similar to something I have here

It's also worth grounding together the CPU and ROM boards, I've experienced unstable behavior with SC1's when the ROM & CPU boards were not directly grounded together, only via the power cable. The original metal plate provided and excellent jumbo ground plane it would appear

I posted about this on RGVAC a while ago.

http://groups.google.com/group/rec....lecting/browse_thread/thread/f1b4bc551f464426

- James

 

[modessitt]

The original metal plate provided and excellent jumbo ground plane it would appear


- James

Which is why I have the metal plates set up for my testing - when I don't us an actual game, that is....

 

[YellowDog]

The original metal plate provided and excellent jumbo ground plane it would appear

- James

It was also a fairly good RF shield. It's probably a good thing that everybody has cable or DirectTV now because the early machines came out well before the FCC and their "computing devices" rules. Most only barely passed the B class rules.

ken

 

[mspaeth]

It was also a fairly good RF shield.

A one-sided RF shield?

 

[YellowDog]

A one-sided RF shield?

It was highly directional. When they were working on Splat! the programmers nailed the boards to the wall, until one of the neighbors brought Polaroids of Splat! playing on his TV and threatened to send them to Atari.

One of the hardware engineers went up and nailed a monting plate to the wall, grounded it and "taught" the boys how to use a screwdriver.

We never heard from the neighbor again, but that may just have been the mob connections at work (never threaten the mob).

ken

 

[mspaeth]

It was highly directional. When they were working on Splat! the programmers nailed the boards to the wall, until one of the neighbors brought Polaroids of Splat! playing on his TV and threatened to send them to Atari.

I call bullshit.

There is absolutely no way the video could have gone from RGB to NTSC modulated up to a VHF carrier frequency and transmitted to a TV w/o significant external circuitry.

RFI is there to suppress noise from the high frequency clocks radiating off the traces... lower frequency signals, there's less of a possibility of finding a trace that would act (well) as an antenna.

 

[docfrankie]

how about april fools

thats some funny stuff

 

[jrok]

how about april fools

thats some funny stuff

Some people take things too seriously to spot a joke

 

[YellowDog]

Dammit Doc! I almost had him......

Actually, it didn't show pictures, but it would knock out channels 2 and 3 for several blocks in the direction the back of the boards were facing. To stop it, they had to put a copper mesh cage around the top of the Splat! boards as well as the mounting plate until the engineers figured out what was going on. It had something to do with the modified ROM board they were using. It was a breadboarded/wirewrapped contraption that plugged into the DMA sockets as I recall. I am assuming that it eventually became the Special Chip 2s although that was after I was gone.

The one very important tool that has been left out of this discussion is a good set of the original Williams manuals and drawing sets. The schematics get used as much or more than any other tool when I am trying to figure out what is going on.

ken