Main > Monitor/Video Forum
Wells Gardner D9200 - Horizontal Collapse?
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.
Rocketeer2001:
I did some further testing this weekend. I was able to borrow a thermal camera adapter for my phone, and using this I could inspect the boards while they were running in the cabinet. Photos aren't the highest quality, and the angles are weird due to the space limitations of shoving my hand and phone inside a live cabinet.
I didn't find anything outrageously hot, but I did get some results. Keep in mind, these images show the hottest thing in the camera's view, and the coldest. Usually that range is from 22°c to 28ish.
In the power section, I can see some resistors and diodes get warm, but nothing unreasonable (see pic).
There's 3 resistors near the back (R137, R138, R196) that get up to 48°c, but I think that's normal for giant resistors like this (see pic).
On the neck board I can see the main IC201 gets warm, as do the large heat sinks, but nothing hotter than 31°, so it seams fine.
The signal input board has a couple of diodes in the corner that get pretty hot (45°) but I recall the dude in one of those youtube video's I posted saw the same thing happening to his board. I guess it's normal. I tested the diodes and they still work, so I guess it's fine? (see pic)
The one thing that really caught my attention was this somewhat hot spot over by R469 (the big ceramic resistor). R490 and IC404 were in the middle of that. I have a different pic where that IC is up to 55°, which is suspicious to me (to be continued).
And I was curious what the tubes neck looked like so I snapped a pic of that for fun.