Wells Gardner Monitor Doesn't Start

[Titan91]

I have a WGT1431 - M1DM56K 13" monitor that chirps repeatedly when powered up. This is the x-ray protection/over voltage protection circuit resetting so I checked the HOT with a meter and it tests fine. Flyback visually looks ok, no cracks or burns that I can see. Can someone provide a schematic for this chassis? Also is there a website that has all the schematics/parts listings for these monitors? Google is turning up nothing for me on this monitor.

Also what caps associated with the HOT would I need to replace? I don't have an ESR meter and prefer the shotgun approach. Also when I tested the HOT/damping diode the meter read short for a brief moment then have a normal 500 ish reading. Does this suggest a compromised transistor/diode or is that simply the capacitive properties of the HOT?

[happyfunball]

wow, its like this monitor doesn't even exist. I tried looking it up on wells gardner's site, bob roberts, and just a google search and all that comes up is an ebay posting.
bob doesn't even have a cap kit listed for it. any idea how old this is?

maybe try asking over at KLOV?

[Titan91]

A undocumented WG, that's unexpected. I actually have 2 like this that aren't working, but haven't looked at the second one yet. I'll try to get part #s from the board itself. Thing about KLOV now is they want $2 to join and their recommendation system isn't working... doesn't make sense to require your credit card number just to post, seems a little shady.

[yotsuya]

A undocumented WG, that's unexpected. I actually have 2 like this that aren't working, but haven't looked at the second one yet. I'll try to get part #s from the board itself. Thing about KLOV now is they want $2 to join and their recommendation system isn't working... doesn't make sense to require your credit card number just to post, seems a little shady.

The $2 fee on KLOV is to prevent spammers, and trust me, it's worth it. The amount of information and literally FREE items people have given me over the past few years is worth well more than $2.

[happyfunball]

its worth the 2 bucks. trust me. just do it.

the amount of stupid questions that have been answered for me goes way beyond the 2 dollar price tag. although when I signed up that wasn't neccesary. seems to be a new thing.

[mgb]

As far as caps and using an esr meter goes, I say that's the one situation where the shotgun approach works well.
  It's best to replace all electrolytic caps at one time.
I can never see the point to pulling out an 85 cent capacitor in order to test it and see if it needs reacement.

As to the other issues, did you verify that it's the X-ray protection circuit that's causing shut down. This can be verified by removing the diode from the circuit and powering it up.

I've never seen this WG model number personally. Is it possible that you took the wrong number, like maybe one particular board number.
  Arcarcxmission.com has a few WG 13" monitor manuals but nothing close to this number.
I have alot of good Randy Fromm Arcade School info at home. I'll see what I can find tonight.

[mgb]

I just googled it and it looks like its a touch screen VGA?

[Titan91]

It's not the $2, they want your credit card # just to post while all other forums just accept voluntary donations.

Which diode should I lift to verify it is or is not an X-ray circuit issue? And yes it is a touch screen VGA. The part # is correct. It's a 2001 monitor from a GlobalTouch2002.

[Titan91]

Ok so I tried the second monitor, does the exact same thing. HOT tests fine on both. However, both use a different (but similar) flyback. One is a WG 1925208 and the other one is a WG 1925195. If I had the schematic for this chassis I could start getting more info including the flyback pinout to see if that's the issue. But I'm getting many many shorts when testing various pin pairs on the flyback, so that's what I'm suspecting. But if the flyback is shorted wouldn't that take out the HOT/main fuse?

[ed12]

of course u are going to see a short across the flyback pin's
for the hot no olny the diode :out of circuit of course:
up-load a pix of this monitor
me think's it is not a wg >chassic<

ed

[mgb]

The ticking/chirping does sound like it'd be a bad HOT on a switched power supply monitor like this.
I read that on some monitors you can't test the HOT by the metering from the metal case to the frame and that you would have to meter collector to emitter

[Titan91]

Took some proper HOT readings and everything seems to check out:

Base to left: 515
Base to right: 560
Collector to emitter and vice-versa: 68

The damper diodes also read 448. Another thing I noticed while I was looking at these boards are cold joints at the yoke header pins. I know that running a monitor without a yoke connection can damage the chassis, could that have happened here as well with cracked joints? With the HOTs and damper diodes checking out could it really be something that simple?

[ed12]

yup and yes and yup
re-flow the joint's

ed

[Titan91]

Reflowed the yoke pin joints, no luck. Gonna pull and test the flyback next. I Googled the part number and the only result I got was where I posted it in this thread. Again, the 2 flybacks are WG 1925208 and WG 1925195. I need to know where the windings are. Are flybacks typically set up the same way across manufacturers? If I can't find that info I'll just do an exhaustive continuity test (test pin 1 with the others, pin 2 with the others, etc).

[Titan91]

Any ideas on where I can find a schematic for this monitor? Flyback info?

Update: Got pictures of the chassis...





Also pulled and tested the flyback with a meter on diode test. Pin pairs and results (short or open). Red lead on the first pin in the pair and black on the other. Not exhaustive but should be enough info to get an idea if the transformer is good or not.

1-2 S
1-3 O
1-4 O
1-5 O
1-6 O
1-7 O
1-8 O
1-9 O
1-10 O
2-1 S
2-3 O
2-4 O
2-5 O
2-6 O
2-7 O
2-8 O
2-9 O
2-10 O
3-1 O
3-2 O
3-4 O
3-5 O
3-6 O
3-7 O
3-8 O
3-9 S
3-10 O
4-1 O
4-2 O
4-3 O
4-5 S
4-6 S
4-7 O
4-8 S
4-9 O
4-10 S
5-1 O
5-2 O
5-3 O
5-4 S
5-6 S
5-7 O
5-8 S
5-9 O
5-10 S

[lilshawn]

send an e-mail to someone at wells gardner. i'm sure they can provide you with a schematic.

I'd ignore the flyback for now. if it's failed, it would probably be pretty obvious.

change all the caps. they look original and are 30 years old now. they are probably what's causing the issue. caps get old and are more of a load than helping the system.

[ed12]

holy crap
i can see no less then 10 bad cpas in that pic alone
recap that puppy

ed

[mgb]

holy crap
i can see no less then 10 bad cpas in that pic alone
recap that puppy

ed

Really? Maybe I'm missing it but I see 3 or 4 with shrinkage.
But for the low cost vs the issues fixed, I do agree a cap kit is worth it definitely.