Wells Gardner D9200 - Horizontal Collapse?

[Rocketeer2001]

Hi everyone! First time poster here.

I've recently acquired a Big Buck Hunter II: Sportsman's Paradise and it has seen some action. The guy I got it from said the machine would turn on, but the monitor wouldn't work and crackles, pops, and sparks would shoot out of the back. After a lot of research I learned I have a dreaded 27" Wells Gardner D9200 monitor. This is where the rabbit hole of woe and sorrow started. Apologies in advance for the long post.

I began by fixing some broken ground wire connections and fixing some solder joints. After that, the monitor would work, but still made crackling sounds every now and then, and the picture jittery at times. The common fix for these issues is to replace caps, so I replaced all 76 of the electrolytic capacitors (and made a list of every single cap if anyone wants it). That smartened up most of the issues. I could then see the monitor has some burn-in (not much I can do about that) and the image was rotated slightly counterclockwise. I adjusted VR101 to rotate the image, but it was already cranked as far as it would go so nothing could be gained there. I foolishly thought "I've manually fixed a rotation problem like this on a TV before, I'll just do that here". I didn't know at the time that the yoke is adhesive bonded to the tube's neck.

I could see there was hot glue all over the yoke, so I used a soldering iron to melt it away. I managed to get it to the point where I could wiggle the yoke, and I could twist it about 1 or 2 degrees, but it still offered resistance. This was enough to get the image straight though, so I just taped it in place temporarily while I adjusted other settings like color and gain, etc. I really wanted to get the colors better than they were, so I was attempted to hook up a laptop using a VGA cable so that I could run a CRT test pattern, but that darn chassis board would not play nice with my laptop. It might have been a resolution setting in the laptop, or it's something on the chassis board. I eventually gave up and put all the connections back to stock.

Shortly after this I wanted to see if I could copy the contents of the hard drive onto a CF card to use that for a boot drive because the original hard drive did not sound happy and I anticipated that any day now it would pack it in. That process is a whole nother story, but during the attempts to use the card is when the D9200 suddenly started making a horrible high screeching frequency noise and the image started experiencing what I think is horizontal collapse. When the machine boots up the text is all wobbly / jittery / zig-zaggy (see photo), but when the game is finally loaded, it actually looks like it's displaying "fine" but is just squished into 2" wide (see photo).

Here's the things I've checked so far:

Q412 - checks out fine
Q413 - checks out fine
Q414 - checks out fine
Q415 - checks out fine
Q425 - checks out fine
Q426 - checks out fine
Q427 - matches Q426
Q428 - had to remove it from the board, but checks out fine

D417 - checks out fine
D423 - checks out fine
D424 - checks out fine
D426 - checks out fine

VR402 - is good
VR101 - not good! Supposed to be 10k ohms but only got up to 4k. Likely the cause of my crooked image in the first place. I'll be replacing this one.

R312 - good
R314A, R314B - each read 0.4 ohms, but I didn't remove them from the board, but if I did I think they would read the expected 1.3 ohms
R318 - good
R415 - good
R418 - good
R424 - good...I think. It takes a while, but it eventually climbs up to 15k ohms.
R462 - good
R480, R479, R78 - each read 0.3 ohms, but I didn't remove them from the board, but if I did I think they would read the expected 1.5 ohms
R853 - good
R854 - good
R855 - good

Things I know I should check but haven't:
IC 404
IC 403
I don't have a way to test them powered up. The monitor is still in the cabinet and I have the chassis board on the workbench.

Some of those parts I de-soldered from the board to measure them individually, but some of them I tested still in the board. The only ones I removed were ones that were throwing out suspicious numbers. If it was close to the stated resistance value found on the schematics, I left it on the board to check.


I've done a lot of internet browsing for possible answers and spent a couple weekends attempting to fix this, but I'm still at a loss, so any insights you have would be greatly appreciated. Or should I just yeet this thing into the sun and find a 27" TV with S-video input and use that instead?

[grantspain]

do you get full deflection with video signal disconnected?

[Rocketeer2001]

Good question! I have not attempted to turn it on with no signal connected. If it displays the boot text normally with no signal, that would mean there's something wrong with the IC that does the resolution switching, yes?

[grantspain]

the max res on these is svga, some of these chassis revisions only go vga as the components are not on the chassis - i wonder if you went past the max res and damaged something, i doubt it would be ic, maybe a fet or transistor but looks like you checked most of them. q418 checks ok?
see what happens with no signal

[Rocketeer2001]

It seems like it should be a transistor to me too. I did take out Q418 and checked for resistance between pins, and it did give results. I have read other posts where these components were fine out of the board, but when they were on the board and powered up, they would start to overheat and mess up the values, thus not work properly. Maybe that's what's happening?

I should probably explain how I'm testing the parts. I'm not electronics expert, so I've just been googling these things.

For Mosfets I was putting the multimeter in diode mode, then measuring the center terminal to each outer terminal. I should see around 0.5V on one leg and nothing on the other.
I could also measure their resistance between outside terminals and get around 1.2 ohms.
I could also measure for continuity between the outside terminal. There should be none.

For Transistors, I'd use diode mode on the meter, measuring between the center leg and either outside leg. They should read around 0.6V

And because I'm not sure if any of that is correct, if I had the component off the board I tossed it in my transistor tester. It's a common gizmo that tests much more than just transistors (see pic).

[grantspain]

yes diode test is what i use, in general a bad fet or transistor will read a dead short if bad. I have had a transistor fail and not read dead short but will have an odd reading

[lilshawn]

i suspect a cap has gone out of spec in the horizontal tuning (search 400 area)... or a FET has gone bad (one of the ones the chassis uses to switch to tune the Hfreq)

also suspect anything attached to CS1/CS2/CS3... find your Hf logic in the table for your frequency you are running and check for shorts in the caps/opens in the resistors/transistors/fets attached to them (IRF640's etc) C455 C456 etc. so on.

[Rocketeer2001]

Sorry for the tardiness, it's been a busy week. Finally got some time to work on this today.

Before I put the board back in the cabinet and turn it on without an input signal, I wanted to check over a few more components since the board is already on the workbench.

I read that the deflection yoke could cause horizontal collapse if it's busted, so I tested the resistance of the coils and got 0.2 ohms for the horizontal and 2.3 ohms for the vertical. These numbers seem low, right? Then again, I don't know what the resistance should be on a D9200. If it's noted on the schematics, I couldn't find it. Anyone have a D9200 they could measure to give me a ballpark? I attached a pic so you can see the stellar condition it's in.

I then removed transistor Q418 to check it again. I use my LCR tester to check all sorts of parts, and normally it will identify what the part is and give you a little diagram with the resulting values (see pic of Q428 and Q430 to see what I mean). Q418 was identified as a "resistor", which seems odd to me (see pic). I did a diode test afterwards with my multimeter and I got 0.262V between center and one leg, and 0.334V between center and the other leg, which is what I think are normal, so Idunno.

Following lilshawn's advice, I checked a few other transistors and didn't see any issues. Then checked the big C456 polypropylene capacitor and got 0.304uf as a result (see pic). Schematics say it should be 0.24uf, so that seems close enough. Decided to check the other 4 big polypropylene capacitors but they were all stuck together with some kind of glue, so they had to be removed as a clump (see pic). The results I got are below [figures in these brackets are what the schematics say the values are]:

C430 [1.2uf, 440V] = 1.18uf, ESR 0.23 ohms
C438 [0.39uf, 440V] = 0.303uf, ESR 0.09 ohms
C455 [0.15uf, 250V] = 0.319uf, ESR 0.10 ohms   This one looks to be double the value it should be. Too far out of spec?
C475 [394pf, 440V] = 390.4nf, ESR 0.09 ohms  This one is rated in picofarads, but my result was in nanofarads. Right numbers, but wrong scale. I should have got 0.3904pf.


What do you guys think is the biggest issue here? The yoke, Q418, or these last couple capacitors? Or all the above?

[Rocketeer2001]

Apologies, I'm trying to upload all the photos but I keep getting errors. I'll try again in a bit, I guess.

[grantspain]

the transistor reading seems odd to me, i would expect collector/base 0.450 and emitter/base 0.500 or around that sort of range

your yoke looks pretty bad, the yoke in my experience are one of the most common failures on d9200 - they just corrode due to the crt suface paint flaking off and rotting the windings or actually burning out. One of the horizontal pins on the connector has been burning for some time, it could be poor connection

c455 is well out of spec but are you going from the component marking or the schematic, c475 looks to be completely wrong but if its marked 394 then the cap is 390nf

I think first thing to do is check all the codes on the caps and if they all match then replace the yoke connector pin

I am leaning towards corroded yoke but that normally causes dead short to HOT and blows, the fault you have on a chassis with a good yoke would be down to an out of spec high voltage poly cap - it could be any of the poly caps rated from 250v to 1.6kv . An example of this is a polo 25 chassis i had this week whereby the 3.3nf 1.6v cap was bad, chassis ran but eht was high and the width control had no proper range

[grantspain]

i take back the readings on q428  should be about 0.640 on those junctions

[princess prin prin]

I tested the resistance of the coils and got 0.2 ohms for the horizontal and 2.3 ohms for the vertical. These numbers seem low, right? Then again, I don't know what the resistance should be on a D9200.

Low resistance (and inductance) is what you find on the horizontal coil of monitors that can do 31KHz so 0.2 ohm is fine to me. If you have an LCR meter measure the inductance, it should be in the 0.2-0.3 mH range.

I then removed transistor Q418 to check it again. Q418 was identified as a "resistor", which seems odd to me (see pic). I did a diode test afterwards with my multimeter and I got 0.262V between center and one leg, and 0.334V between center and the other leg, which is what I think are normal, so Idunno.

Q418 is an NPN transistor so it tests like any other NPN, with Base-Collector being one P-N junction and Base-Emitter being the other one. This means that you'll have voltage drop readings only on those (with red probe on Base). You should have about 0.45V on B-C and 0.50V on B-E (all 2SC5144, all test similarly):

[Rocketeer2001]

The one wire on the yoke connector does look like it's been getting hot, but the actual pin inside is still clean and makes a good connection.

I can probably use the LCR meter to test inductance of the yoke. I've never tried, but it's a feature-packed little device, so I'll give it a go.

I did notice that C456 on the schematic is 0.24uf, but the actual part has a '304' on it (see pics), so you're probably right that the components used don't match the schematic and I should just check the labels on the parts instead. It just means I have to split that glue to get them apart. I hope the labels don't get ruined by this and become illegible.

If Q418 is just a big NPN transistor, then I would expect the LCR meter to identify it as so. It identifies all functioning NPN transistors, so I'm leaning towards this being the culprit. I kind of tested it backwards in diode mode with the negative probe on the base.

Lets see if the pics will upload this time...

...nope, still get this error that says "your attachment has failed security checks and cannot be uploaded". Not sure what security check it's failing. It's under the size limit and it's just a jpeg, like the other photos I posted. Is there a limit to how many photos can be posted in 24hrs or something?

[grantspain]

i thought it was q428 that was reading bad, its a 2sc945c and is part of the frequency circuit and would certainly explain your issue as the chassis would not be able to find the right frequency
q418 is the horizontal output transistor, 2sc5144 and should read exactly as princess prin prin has shown

[PL1]

Lets see if the pics will upload this time...

...nope, still get this error that says "your attachment has failed security checks and cannot be uploaded". Not sure what security check it's failing. It's under the size limit and it's just a jpeg, like the other photos I posted. Is there a limit to how many photos can be posted in 24hrs or something?

Unfortunately, the forum software sometimes throws false positives during the security checks.   
https://forum.arcadecontrols.com/index.php/topic,164181.0.html

The best known workaround is to either crop or resize the image by about 3-5% and try uploading it again.


Scott

[Rocketeer2001]

I hooked the LCR meter up to the yoke and got:
2.8 ohms, 0.23mH for the Horizontal and
9.3 ohms, 5.71mH for the Vertical
Those readings look much better than what my multimeter spat out, and is close to that 0.2mH range you mentioned, so it looks like the yoke is good! (whew).

I hadn't actually looked up the spec sheet for Q428 because it didn't look vastly abnormal at a glance. Is the hFE or Uf no good? Is that the 0.64 you were talking about?
Makes me second guess if any of the transistors I tested were actually good. If the LCR meter didin't show a fault or incorrectly identified it, I assumed it was good.

The Q418 transistor definetly doesn't read 0.5v, so maybe it is kaput.

I broke apart the group of poly caps so I could read their labels and only got a 75% success rate. That white paint or epoxy or whatever it is absorbed the ink from the label, so when I scraped that off the ink went with it. I have no idea what C455 is supposed to say, which is of course the only one I really wanted to know, but all the other ones matched the schematics. Well, mostly; the other 3 said they were 440V MMP on paper, but the actual parts are 400V MPA. Not sure if that's a big deal.
So do I trust the schematics that C455 is supposed to be 0.15uf? Mine reads 0.319uf, which would be wrong.

C456 reads 0.30uf when it should be 0.24uf. Big enough of a variance to warrant replacing?

Do Q418 (and maybe Q428) seem sketchy? Should I just replace all those parts and see what happens?

[princess prin prin]

The HOT is definitely at fault (leaky) as you should have OL with the probes connected like that (or whatever your meter displays when the probes are disconnected).

Your 2.8 ohm reading isn't correct for the horizontal yoke (looks like your meter was doing a better job here).

[Rocketeer2001]

Prin prin, I took out the Q418 again and hooked it up to my multimeter in the same configuration you did. It said 0.32v and 0.08v. I think we can confidently say that its broken. I'll get a new one of those.
What would cause that to fail? Or is being 21 years old reason enough?

Should I replace C455 as well? I mean, it must be a cheap part. I might as well just get one and hope the schematics are accurate and it's a 0.15uf, 250V.

Anything else I should be ordering just to be safe?


Scott, thanks for the suggestion about cropping the photos! It's a bit inconvenient, but it does work.

[grantspain]

don't get a 2as5144 to replace q418, get one of these
https://www.mouser.com/ProductDetail/onsemi-Fairchild/FJL6920TU?qs=CR8BwU6haLdFGBuY0BHhSA%3D%3D

i would also replace q428, 2sc945c and c455

[Rocketeer2001]

Hey Grant, I did discover before your reply that the stock Q418 part number of Toshiba 2SC5144 was hard to find, and the ones I did find were questionable. I did find the alternative part number for the Fuji FJL6920TU, so I'll go with that.

I'm thinking I'll remove these transistors and check them again with the LCR meter, since I'm clearly a novice at determining which are good and bad. Some of them are similar to Q428 so might be failing too:

Q412 - C945C-Y
Q413 - IRF644
Q414 - 2N7000
Q415 - IRFS640A
Q423 - C945C-Y
Q424 - A733C-Y
Q425 - C4770
Q426 - IRF630A
Q427 - IRF630A
Q428 - C945C-Y (this is the CS2)
Q430 - C102M (this is the CS1)

I don't have a CS3 so there is no Q429 or Q416 on my board.

See anything else worth checking? Just want to make sure I order all the parts I need at the same time.

[grantspain]

i think the 3 components, q412, q428 and c455 will do the job.
but if you have time it can't hurt to check all the compoents you list
i reckon q412 is causing the frequency problem, c455 is causing the horizontal size problem. q428 is the odd one here as its reading strange but not short, definitely needs replacing though

[Rocketeer2001]

Grant, I hope it's ok if I lean on you for your expertise here. I used my LCR meter to measure all these parts. See anything amiss? In my little label, I have the Q number, then the schematic number, and then the actual number that's printed on the part:

[Rocketeer2001]

and the last 4

[grantspain]

as far i can see all those read correct

[Rocketeer2001]

Ok!

Interestingly, that Q428 that you didn't like the looks of before, is now ok. I have similar conflicting results with Q430. I think the first time I removed them to test them I slapped them in the meter perhaps too quickly, and they were still too warm from the heat transfer of the soldering iron, which would give me screwy results. See the pics of the before (the first test) and after (yesterdays test). I just realized after looking at those numbers more carefully, that maybe I mislabeled my original photos from my first test, and they're actually the reverse...I'll go test those two transistors again just to be sure, haha.

Guess I'll just be ordering the Q418 and the C455. Dangit, I just noticed that in the schematics it says this cap is a 250V, but in the parts list it says its a 440V. If I recall, it's ok to get caps with a higher voltage rating than what they came with, so should I just get it as a 440V?

[lilshawn]

higher voltage is okay. you typically spec a cap for about 2x the voltage... then the next closest working value up from that.

so for a 150v power rail, i'd spec out like a 350v capacitor (150+150=300) i'd probably only have a 300v, a 400v, or maybe even a 1000v in my bin and it would probably be completely fine to use any one of them... and for a 12v power rail a 25v cap. (12+12=24) and although it would be perfectly okay to use 16v capacitor...i'd probably spec a 35v cap anyway anyway since it's more common than 25v caps and the size difference isn't too much and it adhers to the "rule"

the rating is often fairly overspec'd for it's labeled working voltage anyways. it's basically the rating the dielectric insulator breaks down and allows current to pass through it unimpeded. chances are, a good cap will (albeit unhappily) take 2x it's rated voltage before ACTUALLY breaking down... it would probably change it's value much sooner running it constantly over voltage like that... but even factoring in your back-of-the-napkin estimates of doubling the working voltage of the circuit, you are really in the 3x neighborhood of being overspec'd anywhos.

i think that rail maxes out at like 195 or 212v? something like that? depends on the resolution... but i think a 250v is probably perfectly fine... it doesn't adhere to the 2x "rule" per se, but is still within the working voltage it's rated at... and probably why someone changed the part list to say 450v

[Rocketeer2001]

Ok, good explanation! I picked out a 400V one. They had a 250v, but it was oddly tiny in physical size, and they had a 450v but was also tiny. The 400V one was the closest in physical size to the old one, and had all other specs matching what I needed.

When the parts show up, I'll get them installed and report back.

Thanks for the help so far everyone!

[Rocketeer2001]

The new parts arrived in a day, so I installed them today in the board and put everything back in the arcade cabinet. Turned it on and for a split second it seemed like it was working! But then I saw that new Q418 horizontal transistor sizzle around it's edges and the heatsink with electricity, then the whole board let out a horrible screeching noise and we're back to collapse.

I'm thinking whatever part broke the original HOT has now cooked my brand new HOT. Or my new HOT was faulty, or the new C455 capacitor was faulty, or something else?

[grantspain]

what heatsink compound did you use and insulation sheet?

[lilshawn]

check D416 and D417.

and yes, you should be using a mica sheet and silicone heatsink compound.

the hot must be isolated from the heatsink.

[Rocketeer2001]

I used thermal paste for a computer's CPU heatsink. I put that on both sides of the original mica sheet and placed that between the HOT and the heatsink. I don't know if the paste has silicone in it; is that specific ingredient a requirement?

I had checked D417 before and it was ok, but I'll check it again. I didn't check D416 yet, but I will. I'll check D422 too.

I tried disconnecting the input signal to the board and turning it on just in case it was the frequency switching transistor running amuck, and I don't get a constant screeching. More like 1 second intervals of a clicking sound (a relay?) with arcing occurring around the HOT.

[lilshawn]

i say "silicone" because lots of thermal pastes for computers contain metals (silver etc.) or carbon and cannot be used in this application due to their electrical conductivity.

you need something like MG chemicals 860 ... basically plain white heatsink grease.

if it's gray, chances are pretty good it has conductive stuff in it.

normally it wouldn't matter... but at voltages and currents like this... it does 100%

[Rocketeer2001]

The thermal paste I use is grey, so I put my multimeter in continuity mode and shoved the probes into a glob to see if it conducts. It did not. Then again, it is just measuring using the voltage the multimeter can provide, which is only 1v or so. I'm guessing at the higher voltages the HOT puts out, this stuff could conceivably conduct. I'm uncertain, but I'll get some of the MG 860 stuff just to be safe.

The mica sheet was in there, but upon closer inspection it looks like it's de-laminating? Also now has some char marks. I should probably just get a replacement.

I removed the transistor to test it to see if it's toast, and surprisingly it's still good! (see pic)  However, I had a suspicion that the part was arcing/grounding too easily, so using my multi-meter I probed within the mounting hole and the back of the transistor and I get continuity. Not everywhere in the hole, but in a few locations. It must have had a thin layer of insulation or something because it was shorting out to the mounting screw and thus into the heatsink. Some of the part has crumbled away around the hole from where the arcing was occurring (see pic), but there are other parts of the hole that look perfectly fine, yet the meter still shows continuity when probed. I'm thinking maybe I got a faulty part (in conjunction with my possibly incorrect thermal paste and de-laminating mica).

I then proceeded to test D416, D417, and D422. The first two were good, but D422 is suspicious. It shows 0.28v in diode mode when the other two show 0.5V. Could this be a contributor?

Also tested my new capacitor and thankfully it's fine!

[grantspain]

you can compare d422 to d423, if they read the same then all good
the insulaton sheet you need is for TO-264  transistor package type

[Rocketeer2001]

Grant, Good suggestion on comparing to D423 since it's the same part number. After checking, it's got the same voltage; Looks like my D422 is good!

Thanks for providing the package size of TO-264. I wouldn't have known what to look for otherwise. Even so, I'm having trouble finding that size that won't cost an arm and a leg. If I buy 300 of them, it's a bargain!

How do we feel about using silicone sheets rather than mica with compound? If I use the sheets, I can cut it to whatever size I need and I wouldn't need the compound:
https://www.amazon.ca/100x100mm-Efficient-Conductivity-Resistant-Silicone/dp/B096ZNHY8F/ref=pd_sbs_d_sccl_3_2/144-4490169-7451254?pd_rd_w=heB6B&content-id=amzn1.sym.4b791088-03f0-49af-8af1-ae2f52d6208b&pf_rd_p=4b791088-03f0-49af-8af1-ae2f52d6208b&pf_rd_r=6FAWM4WQCSZ53FYBVCVG&pd_rd_wg=4316Q&pd_rd_r=4a0bdac6-e605-491f-bdf8-ecf523b85029&pd_rd_i=B096ZNHY8F&psc=1

Arcade Parts & Repair sells both kinds, but because I'm in Canada it's over $20 for a $2 part...
https://www.arcadepartsandrepair.com/store/integrated-circuits/transistors/mica-transparent-insulator-to-264-package-5-pieces/
https://www.arcadepartsandrepair.com/store/pinball-kits-parts/pinball-parts/mica-silicon-insulator-to-264-package-5-pieces/#reviews

Or I get the MG compound and just reuse the original mica.

[grantspain]

not sure, it would probably be ok if you got the thinnest one. i would still use thermal past with it.

your original mica sheet is knackered, thats what is causing the arcing and it most likely to have been the fault all along

[princess prin prin]

You can also use a TO-3PL (22*29*0.12mm with hole). This is cheap if you don't mind waiting:

https://www.ebay.com/itm/324673667376

[lilshawn]

typically the silicone pads used for transistors has a fiberglass fabric inner layer to keep the silicone from squeezing out and puncturing when the transistor is screwed down.

they are also only 0.3mm thick.

[Rocketeer2001]

Grant, thanks for confirming the old mica should be tossed.

I did some reading and although the thermal pads are easier to use, I couldn't find consistent claims that it would insulate against the higher voltages, or that it was substantially better at thermal conductivity than the mica. Looks like it's a good substitute for computer CPU heatsinks though. Shawn, I did read about the various silicone pads and how some have that fiberglass layer, but I wasn't finding good sources for it. A lot of items just claimed it was a silicone thermal pad, but didn't really mention enough details regarding its properties. We know the mica works and lasts a long time, so I'll just go with that and get the accompanying compound.

Prin, I did stumble across the size compatibility of the TO-3PL, and that same ebay link! I ended up ordering some of those and payed a few bucks more for faster shipping. It's still going to take about a month, so our little adventure here will have to pause for a bit. TO BE CONTINUED...

[lilshawn]

typically the cut to fit silicone pads like what you had linked are for filling space between a device and a heatskinking material like the back cover case of a device... where you want to remove excess heat, but not real concerned about how much.

you quite often see them in TV's where the main video processor has a pad that makes it so there is contact with the metal backing of the LCD panel. it sucks out SOME heat...but not a real lot.

you also see them on VRMs and ram  chips for video cards to get some heat out to the heatsink.

more of a space filler than anything else.

[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.