Wells Gardner D9200 - Horizontal Collapse?

[Rocketeer2001]

That's the impression I was getting looking at all the ones for sale. Thanks for clarifying!

The replacement transistor has arrived, and the MG Chemicals silicone compound has also arrived. Now I'm just waiting on the mica.

[Rocketeer2001]

I'm back!

Got the replacement transistor for Q418, the MG silicone heat compound, and the mica sheets. I think the quality of mica sheets has severely declined since the early 2000's. I could only order them in a pack of 20, and out of all those only 1 looked somewhat better than what I already had.

Anyways, put all that stuff back on the board, put the board back in the cabinet, turned it on and....nothing. I get the *thump* sound when I flick on the power, and the neck tube is glowing, and I can hear a relay clicking 3 separate times, but the screen is black and it doesn't do that frightening electrostatic sizzle a tube typically makes when it energizes.

Seems like I have a power problem now. I don't think I hooked up any wires incorrectly, but I'll go double check. If not that, what else? The flyback? Q401, Q425, IC101, or IC403?

One step forward, two steps back...

[grantspain]

does the sheet fully cover the transistor metal body?

[Rocketeer2001]

Yup! It's the same size as the old one.

[lilshawn]

upstream from the transistor is a fet that can sometime get plotzed when the main transistors go. it'd be Q413. double check that D417 diode pack too if you haven't already. it's hard to tell what the problem is with these monitors since every single system is separate in these chassis, since it sounds like no HV is being produced now... but not sure since you can't actually tell if having the Q418 in there now is working and you have deflection... but can't see it cause of no HV.

if no hv sounds (and not just a horizontal line) you may have to go upstream from both those systems and look at the "h-outctrl" signal coming from the main IC driver chip (IC301 pin 21). if effs off in a tee and one direction goes to the horizontal Yoke drive circuit and the other goes to the drive circuit for the flyback. i'm dealing with a similar issue with a D9200 with "the jitters" and have been pouring over this area for a while trying to find the issue... so i've been getting very familiar with it.

anyway, sounds like maybe that signal has now stopped since you have no HV and previously you did. there is a bit of shared circuitry so it's possible for a failure in one to effect the other. could be worth looking into Q423 Q424...  Q426 and Q427. they are pre-pre-drive transistors and pre-drive mosfets used to drive their respective transformers (T404 and T405) that fire off the h-deflection (2SC5144) and HOT transistors (2SC4770). this is the beginning of the "tee"

make sure you have a +32v power coming in to this part of the circuit at R470, this is the juice used to make the pulses in the transformers by grounding out the other transformers leg to ground through the pre-drive mosfets.

might be a problem with Q413 or D418, since the 170v drive that flows through the 2SC5144 flows through this fet and diode, and grounding that 170v out through an improperly attached 5144 can cause a huge amount of current to go through Q413 and D418. check and make sure you have 170v here as well. if not, you have an issue further up the chain in the power supply (possible blown out R854 or D814 or open L801).

[Rocketeer2001]

Hey Shawn, thanks for the excellent suggestions!

I found 2 faulty parts:
Q413 is completely shorted; all it's legs have continuity to one another and the mounting tab.
Q414 is reading as two resistors instead of a mosfet, so I'm going to assume that one is bad.

Just to be sure, I also checked these parts and they are all still good:
D417
Q423
Q424
Q426
Q427
Q412
Q415
Q428
Q430

I didn't check the IC301 or any transformers or if I had +32v at R470. The two faulty parts you've helped locate are likely the only problem (fingers crossed), unless you think there's anything else I should be check knowing that Q413 and Q414 failed.

[lilshawn]

i would check R854, its a resistor that knocks down the 170 as it comes out of the SMPS. if the 170 line has been overloaded, it's possible the resistor has gone out of spec, causing the voltage to be off.

since both q414 and q413 where both bad, i'd double check everything in that section upstream and down....

R460
c470
D424
c448
C436
D405
C457
R461
R462
D418
D417

basically check the capacitors and the diodes for shorts and the resistors to be within tolerance... having shorted components is a real stressor. hopefully nothing else is wrong, but it can't hurt to check.

[Rocketeer2001]

An excellent suggested list of things to check! I see where you're going with this.

I got started on it tonight but didn't get too far. R854 is fine, but R462 is shot. Has no resistance, so I'll need one of those. I was getting unreliable readings from the capacitors on the board, so I'll have to remove them to test them properly.

To be continued!

[Rocketeer2001]

I proceeded this evening to remove all these components and test them:

R854
R460
R461
R468
D424
D405
D417
D418
D429
C470
C448
C436
C457
C442
C443
C419

Out of all those parts, none of them were bad. They are all fine. The only new failed part I found is the same as yesterday, the R462. I'll put in an order tonight and hopefully have those before the weekend.

Shawn, I hope you're getting somewhere with your D9200 as well.

[lilshawn]

thanks, hopefully that you get back up and running again. (or at least closer to running so we can see what else is going on)

my projects get back burnered all the time. I have stuff at work that comes up that needs my priority, so it can take quite a while to get back around to things. i like "explaining" out my repair attempts in my posts, so when inevitably i forget where i was at in my repair... i can swing back and read through my post to jar my memory. 

getting old sucks 

[Rocketeer2001]

I got all the parts last Thursday...except for that one resistor, which shipped separately and didn't arrive until today. Put all 3 parts in and...still broken

It did behave differently this time though. I had the game board disconnected from the monitor so that I could see if the "no signal" appeared on the screen first before trying to boot up anything else. When I turned on the power, there was a sizzle of high voltage going to the CRT, so that was good, but then the chassis board starting making a quickly repeating clicking sound, similar to a geiger counter. There was also the normal clicking of a relay that I heard before, but still no image on the screen.

I turned it off, then reconnected the game board to see if having a signal would make a difference. Turned it back on and the sizzle, clicks, and relay clicks were there again, but this time the geiger counter clicks got quieter and the relay clicks got slower. Sure enough, there was an image trying to form on the screen, but it was all garbled with micro-seconds of dim clarity of the "no signal" image.
*EDIT* The neck was also glowing, so I assume that means it's getting enough power to run the tube, but just isn't getting a good video signal.

Then there was a loud BANG and I saw a spark at the neck board. I shut everything down, let it cool down for a few minutes then took the neck board off to see if any components exploded. They all looked visually fine; I think it was just a grounding discharge. Not sure why that would happen.

The new clicking sound was coming from the same corner of the board that all the horizontal collapse components failed around.
The spark on the neck board was just left of the neck if you're looking at the back of the board.

I haven't taken anything else out to inspect. Getting a little tired of this monitor. Although, it's technically no longer horizontally collapsing, so I guess that's a win. It's just fritzing in all directions now.

I will now open the floor to any questions and suggestions for the next course of action.

[grantspain]

was the bang noise more of a heavy crack noise?
I imagine you remembered to connect the neck card dag earth?
I can't remember if q414 original was a irfs644 or irf644, the latter would require a insulation sheet

[Rocketeer2001]

Yeah, it was more of a snap. Like a quick arc. I did have all the grounds connected so it was a bit surprising if the neck board is trying to arc to ground. It only happened once within 30 seconds of powering on.

Q414 is just a little guy. Like an NPN transistor, so no insulation sheet.

I've been doing some searches online and the common culprit for repetitive ticking noises is the HOT or the flyback dying. I've already replaced the HOT...twice, so is it maybe the flyback? I should probably remove the HOT again and check it to see if it got fried, yet again.

[lilshawn]

it's not uncommon for the main B+ supply to act weird due to a bad feedback capacitors. changing out C413 C314 could stop it from doing the ticking thing.

faint ticking/buzzing with no power and acting "dead" can be a sign that the SMPS controller chip (U802) thinks there is an overload condition and will continually attempt to restart the power supply. it will also sometimes work just fine... then other times it won't want to start again.

if you heard/saw an electrical arc on the neck board... check the resistors. they can look okay on the top side, but if you look carefully at the side of the resistors that is up against the circuit board, you can sometimes find one blown out.

while i wouldn't discount the idea of a failing flyback... you never know with these things. the D9200 D9400 series monitors where an absolute engineers wet dream. they did all the crazy things they thought was a good idea and the next big thing since sliced bread... and sadly... many of them aren't... it just makes 10x the amount of things that can go wrong.

[Rocketeer2001]

I'll give those capacitors a look this weekend. It doesn't seem to be a power issue though, because the neck tube was glowing the whole time, it just wasn't showing a proper image.

I'm wondering if maybe the chassis board is fine, and my issue is actually with the neck board or the video/sync board, because the slight blips of images I got on the screen were of the "no signal" message, but I had the game board hooked up and running, so I should have been seeing blips of the game and not the "no signal". Perhaps the video signal isn't making it to the chassis board?

The neck board and the sync board admittedly don't look fantastic; almost like they might have been exposed to some water damage in the past. Maybe I'll try reflowing all the solder joints on those two boards and see how that pans out. I'll check for burnt resistors too.

If that doesn't pan out, what is everyone's thoughts on just turfing this stupid monitor and using a CRT TV as the monitor? I've been reading up on how to do RGB mods to commercial TV's, and it doesn't seem that difficult compared to trying to track down the issue with this D9200. So far I've spent $75 trying to make this damn thing work, and I know I can't find a genuine replacement arcade monitor for less than $400, yet I can
find an old TV with few miles on it with no image burn-in for next to free on kijiji, and then spend a few dollars on the couple components needed to mod it.

[lilshawn]

the no signal message, as well as the OSD menu is produced locally on the neckboard using a secondary channel on the video amp IC chip.

could be a sketchy +5v rail maybe? if the voltage isn't stable, the computers controlling things could be cutting in and out.

still concerned by the arcing you described.

[Rocketeer2001]

I'm back to report failures. Now, instead of just clicking, there's no image at all. No arcing this time either, which is a plus, I guess. Here's what it's doing:


I checked Q413, Q414, D424, R854, R462 and C314 on the chassis board, and they were all fine. I also checked Q418 again and it's still fine.

Moved on to the input board and checked Q220, Q501, Q502, R518, R525, R516, and two zener diodes and a capacitor that's in the one corner of the board. Everything was fine.

Tried finding any faults on the neck board and there was only a few questionable resistors, but after pulling them from the board R267 and R217 were fine. I then proceeded to reflow all the solder joints on that board. Took over an hour, and apparently didn't help at all.

It became difficult to tell if components on the neck board and input board were bad because the schematics don't match my boards. They had different parts with different values. Kind of weird that there's only one set of schematics for this monitors even though there are multiple revisions of the boards.

I used this guys repair videos to see if there was anything else was worth checking and all the parts he checked were fine on my boards:




Thoughts? Mine are, "That dumpster is starting to look like a basketball hoop, and this monitor is starting to look like a basketball".

[Rocketeer2001]

Another day of testing, and still haven't found the issue. Just to be sure, I removed a bunch of parts from the boards and tested them to make sure previously tested and/or replaced parts didn't fail again. All of these tested good:

C310
C828
C441

D403
D417
D421
D423
D424
D425
D426
D427
D431
ZD403

R314A
R314B
R317
R406
R415
R416
R426
R429
R432
R433
R435
R437
R445
R454
R462
R854
R481
R483
R485
R487

Q401
Q402
Q403
Q404
Q405
Q412
Q413
Q414
Q415
Q418
Q419
Q423
Q424
Q425
Q426
Q427
Q430

Kind of took the shotgun approach and just went at everything.
At this point, I'm either looking at a transformer, the flyback, or an IC. Or I just keep looking in the wrong spots and it's still an elusive diode, resistor, mosfet, or transistor.

What ya'll think?

[Rocketeer2001]

Slight update:

I checked the B+ voltage at the 854 resistor and I have 170v. It warbles a bit between 169 and 173, but mostly stays at 170.

This means my power section is good, right?

Just to reiterate, I can hear the tube static as it powers on, the screen is black, the 'no signal' message is NOT present, and the neck has glow. All the while, something is clicking away constantly in the general area of the HOT. This is without the game board plugged in, so no input signals are present.