U2000 monitor issue...

bongoben

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U2000 monitor issue... intermittently dropping greens

I have a question about a U2000 monitor.

Short version of issue...
This chassis was completely bulled-proofed by Chad @ Arcadecup a year ago. Now it is intermittently (but becoming more frequent) dropping all greens. I've checked the Jamma harness and the input pins on the chassis and they look okay. I have very little knowledge of working with monitors beyond a basic cap kit / replacing a flyback so I have no clue where to look next. Please help.

Longer version of issue...
This chassis is one that Chad @ Arcadecup fixed/rebuilt/bulletproofed about a year ago. Over the holidays as my brother in law was playing a soccer game on that cab the green grass turned completely black. Basically all of the greens dropped out of the picture. The first time this happened it lasted for about 5 minutes then went back to normal for a bit. It happened a few more times throughout the night with the final time happening for about 20 minutes before it went back. Since then when I turn that cab on (the one my Gamebox 450-in-1 is in) sometimes the monitor is fine for the duration but other times it switches from having a red hue (no greens) to being fine. In fact tonight I turned the cab on and it came up messed up and never went back to normal. I have checked out the wiring on the Jamma harness as well as at the input pins on the chassis and see no issues. Beyond that I'm stuck.

I hate monitors... hate working on them... hate trouble shooting them. But a lot of this hatred probably comes from my lack of knowledge about them. I'm really hoping this isn't a tube issue because I don't have the time/energy to search for a suitable 25" tube for a swap. If it really came down to it I'd probably sell the chassis or entire monitor for what I paid Chad for the repair and put that towards a new monitor for my game. Hell, I'd even consider going LCD for this cab since the games aren't of the classic era... and I hate working on CRT's. :)

Any pointers on where I should start to look would be awesome. I wrote Chad about the issues and he said it's probably either in the neckboard or a short in the tube. Situation just sucks because it's the one game my kids really love playing and the beautiful monitor is acting all crappy. Maybe that's why I'm leaning more towards pins recently... no monitors to deal with.
 
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surprised you didn't look at the more obvious spot: the neckboard. it's ok though, I understand your pain.

speaking as someone that's had this problem on a couple U5000s, the U2000 is more than likely plagued by the same exact problem: heat. the color drive transistors get very hot and generally start lifting traces on the neckboard. now you might even be lucky that it's just cold solder, but if Chad worked on it previously, I doubt that's the case.

I'd get the soldering iron out, maybe more-so a desoldering iron/pump, and basically remove the middle of the 3 transistors (they actually go in the same order as the bias trim pots on the top of the neckboard, should go red, green, blue when facing the back of the neckboard... it's been over a year, so it might be reversed too lol) and if you want to get very fancy, trade the green with the red one, solder them back in, and try again.

you SHOULDN'T need to discharge this monitor, I know the U5000s bleed off, and if the U2000 comes with that large white box on the anode, it will too. I guess try not to bump the back of the neckboard on the metal frame if you don't have the cardboard cover on it anymore.

I personally redid the thermal paste on all the drive transistors' heatsinks on one of the monitors I did. I use Arctic Silver Ceramique, you can find it at Radio Shack.

good luck
 
surprised you didn't look at the more obvious spot: the neckboard. it's ok though, I understand your pain.

speaking as someone that's had this problem on a couple U5000s, the U2000 is more than likely plagued by the same exact problem: heat. the color drive transistors get very hot and generally start lifting traces on the neckboard. now you might even be lucky that it's just cold solder, but if Chad worked on it previously, I doubt that's the case.

I'd get the soldering iron out, maybe more-so a desoldering iron/pump, and basically remove the middle of the 3 transistors (they actually go in the same order as the bias trim pots on the top of the neckboard, should go red, green, blue when facing the back of the neckboard... it's been over a year, so it might be reversed too lol) and if you want to get very fancy, trade the green with the red one, solder them back in, and try again.

you SHOULDN'T need to discharge this monitor, I know the U5000s bleed off, and if the U2000 comes with that large white box on the anode, it will too. I guess try not to bump the back of the neckboard on the metal frame if you don't have the cardboard cover on it anymore.

I personally redid the thermal paste on all the drive transistors' heatsinks on one of the monitors I did. I use Arctic Silver Ceramique, you can find it at Radio Shack.

good luck

Cold solder joints on the neckboard and at the video input connector header.

Thanks guys... always appreciate the tips, especially when it relates to monitor work. I'll spend some quality time with the neckboard later this week to see what I can find.
 
Hi Ben, what we should do from this point is have you send just the neckboard back to me.. If it's not your tube then likely now it's an intermittent transistor. I have recently seen this in 2 differnent neckboards with perfect trace rework.. after the tranistor heats up it shuts down color drive.. So that could be your case. Ill cut you a very good deal on the rework.. x3 new NOS original transistors and trace rework. return shipping and a small fee.
 
Hi Ben, what we should do from this point is have you send just the neckboard back to me.. If it's not your tube then likely now it's an intermittent transistor. I have recently seen this in 2 differnent neckboards with perfect trace rework.. after the tranistor heats up it shuts down color drive.. So that could be your case. Ill cut you a very good deal on the rework.. x3 new NOS original transistors and trace rework. return shipping and a small fee.

Diddo Check or just replace the Green transistor-s on the Neck Board That is prob the issue.
 
That's the one... and also replace the 2n3904 in line with it if you have one... I highly doubt such a small signal transistor would be intermittent however you never know.
 
That's the one... and also replace the 2n3904 in line with it if you have one... I highly doubt such a small signal transistor would be intermittent however you never know.

I fired the game up for a bit tonight and the monitor looked great for the first 10 minutes. Well, I did pull off the neckboard to do a quick once-over to see what I could see then I replaced it on the tube and turned the game on. Anyways, after being on for 10 minutes I went upstairs for a minute and when I came back down... sure enough... it was all red again. And you see... that's the issue. I could very easily drop a few bucks on parts and shipping... solder them into the neckboard and test that out but honestly I wouldn't know where to go next if those don't work. The two scenarios that I'm dealing with (in my head)...

1-I hate the thought of putting in alot of time on trying to fix this myself because, as I said before, I hate working on monitors. I can hold my own with soldering and I know that the only way I'm going to learn more about testing different parts out is by getting in there myself and doing it but to be honest I also get frustrated with monitors really easily. And, from what I've been told, a U2000 isn't exactly a great learning chassis.
2-I would love to send the neckboard off to Chad because as far as I'm concerned, he's the best. But... my brain keeps tossing the "what if" around that this might not be the issue. I've already sunk $130 into the chassis to rebuild it from totally dead to actually working. I think of throwing more money into this monitor to hopefully take care of the color issue... but what if that doesn't fix it? What if it really is the tube? To be totally honest, with 3 kids I just don't have the ambition to take my time away from them to go out searching for a tube that might work with this chassis. That's why I say that I'd love to just say fuck it and pick up a nice lcd monitor but I don't have the cash for that either. And yes, I know $130 plus a bit more if I send the neckboard his way is nothing compared to some vector rebuilds so I shouldn't complain. :)

This stupid monitor just pisses me off. It's the one cab my kids REALLY get into because it's anything they could want to play all in one cab but the can't play it because the monitor is being dumb. And it looks so damn good when it is working correctly. The tube is beautiful. Okay, so Chad... if I do send this to you how would be best to disconnect the red and white wires that go from the flyback to the neckboard because they are soldered directly into the neckboard. Do I desolder them? Cut and wire nut?


(edit) before I send it off though I may try switching two of the transistors like mecha187 said. I figure it's an easy enough test before I even begin ordering parts.
 
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I fired the game up for a bit tonight and the monitor looked great for the first 10 minutes. Well, I did pull off the neckboard to do a quick once-over to see what I could see then I replaced it on the tube and turned the game on. Anyways, after being on for 10 minutes I went upstairs for a minute and when I came back down... sure enough... it was all red again. And you see... that's the issue. I could very easily drop a few bucks on parts and shipping... solder them into the neckboard and test that out but honestly I wouldn't know where to go next if those don't work. The two scenarios that I'm dealing with (in my head)...

1-I hate the thought of putting in alot of time on trying to fix this myself because, as I said before, I hate working on monitors. I can hold my own with soldering and I know that the only way I'm going to learn more about testing different parts out is by getting in there myself and doing it but to be honest I also get frustrated with monitors really easily. And, from what I've been told, a U2000 isn't exactly a great learning chassis.
2-I would love to send the neckboard off to Chad because as far as I'm concerned, he's the best. But... my brain keeps tossing the "what if" around that this might not be the issue. I've already sunk $130 into the chassis to rebuild it from totally dead to actually working. I think of throwing more money into this monitor to hopefully take care of the color issue... but what if that doesn't fix it? What if it really is the tube? To be totally honest, with 3 kids I just don't have the ambition to take my time away from them to go out searching for a tube that might work with this chassis. That's why I say that I'd love to just say fuck it and pick up a nice lcd monitor but I don't have the cash for that either. And yes, I know $130 plus a bit more if I send the neckboard his way is nothing compared to some vector rebuilds so I shouldn't complain. :)

This stupid monitor just pisses me off. It's the one cab my kids REALLY get into because it's anything they could want to play all in one cab but the can't play it because the monitor is being dumb. And it looks so damn good when it is working correctly. The tube is beautiful. Okay, so Chad... if I do send this to you how would be best to disconnect the red and white wires that go from the flyback to the neckboard because they are soldered directly into the neckboard. Do I desolder them? Cut and wire nut?


(edit) before I send it off though I may try switching two of the transistors like mecha187 said. I figure it's an easy enough test before I even begin ordering parts.

the G2 wire is probably soldered in cause the flyback was replaced (replacement flybacks for whatever reason lack the OEM connector that you use to plug it in). make note of this with a picture if you want to (the empty solder hole from where you pulled it out will be the obvious point, but just in case :)), and desolder it. the other white wire is the focus wire, it connects into the neck socket. just lift open the lid on that (pull the side of it to unlock it), unhook the wire from the retaining clip, and pull it out. I'm guessing you already know how to unplug the black CRT ground wire.

if I'm not mistaken, tubes can go to a certain tint when they're warmed up. this of course is a case of whichever gun in the tube being shorted, and can only be fixed with a rejuvenator. so do the transistor swap to be sure.

good luck
 
Drop the few bucks on the transistors and if that doesn't do it bring it down next time and I can check it with a rejuvenator. I'll bet it the transistors though. Very easy fix. You can meter them out also before you order them just check the known good colors then compare those readings to the ones you suspect.
 
Drop the few bucks on the transistors and if that doesn't do it bring it down next time and I can check it with a rejuvenator. I'll bet it the transistors though. Very easy fix. You can meter them out also before you order them just check the known good colors then compare those readings to the ones you suspect.

Right on. I was having an "overly tired I hate working on games" moment lastnight. I'll pick up the transistors as swapping one (or all) of those out shouldn't take more than a few minutes.
 
Anybody bought from electronix.com before? Mouser and GPE don't have the transistor I'll need.

(edit)

Hold on... I just found a link elsewhere on KLOV to this site:
http://nte01.nteinc.com/nte/NTExRefSemiProd.nsf/$$Search?OpenForm

So is the 2SC3782 the same as the NTE2507 seen here?:
http://www.mouser.com/ProductDetail/NTE/NTE2507/?qs=2AaWgLtd6/1dWafxXRu3Fg==

If so, what would be the difference between that one on mouser @ $5.79 vs the one in the below electronix.com link @ $1.69?
http://www.electronix.com/semiconductor-2sc3782-p-15900.html
 
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did you order these yet?.. ill just ship you a pair free if you would like.
 
did you order these yet?.. ill just ship you a pair free if you would like.

Nope, not yet. Been too busy with the kiddies in my home to even think about working on this monitor. I was planning on putting it all together this weekend. But wow, if you wanted to send them to me I couldn't turn that offer down. PM Sent.
 
did you order these yet?.. ill just ship you a pair free if you would like.


For the record... I got these parts from Chad in less than 24 hours after he put them in the mail. Thank you very much Chad. I hope I can get the repair done this weekend.
 
often times the pads/traces will lift on those transistors, so be extra careful when you do them. might be in your best interest to leave the legs on the transistors long in case you have to scrape the traces and solder the legs to them if the pads are burned up.

this happens cause the transistors get so hot, even with the heatsinks. make sure you use thermal paste when you install the new ones. I think I mentioned already, Arctic Silver Ceramique (from the shack) is what I use.
 
Just wanted to follow up to this. I finally got a chance to deal with this monitor tonight. Replaced the two transistors on the Green line on the neckboard (that Chad sent me for free... thank you Chad) and poof. It looks beautiful. I had to run a couple wires to deal with lifted pads/traces but they should hold nice and strong for awhile.

KLOV HELP FOR THE WIN!!!

Thanks guys.
 
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