Sorry to ask you guys a computer question again...

[karmaman]

I will check if Fry's has it tomorrow. I just got home, and according to the schematic, Q901 is responsible for HV REG OUT and Q902 is responsible for HV OUT. Would that be directly related to deflection? They are both on a heatsink next to the flyback.

[Eric H]

HV would probably be High Voltage, since you have a line across the screen you have high voltage and the horizontal is working. a flat line scross the screen means your vertical isn't working, could be a bad cap, transistor, IC or solder joint.

[karmaman]

Horizontal is not working, I get a vertical line going down the screen. Or at least, I did for a few seconds before I shut off the monitor. Now, it degausses and then the power light starts blinking.

EDIT: BTW, Q901 and Q902 don't look burned or damaged in any way.

[karmaman]

Bad news.... found some bad caps and swapped them, also did a lot of cleaning to the neck board, there was a load of brown crap all over the place (dried flux I believe). Now, when I try to power on the monitor, I get no degauss, no HV, and no heater voltage. The power light turns green and starts blinking. I'm positive I got all the wires hooked up right.

Help? I knocked a SMT resistor off the board by accident, the value was 0.01MF, 50V. Surface Mount pisses me off, that thing was smaller than a crumb. I was unable to get it back on, then I lost it, so I bridged the two connections with solder. Could that be it? This was on the neck board.

[radiotvnut]

Originally Posted by karmaman

Bad news.... found some bad caps and swapped them, also did a lot of cleaning to the neck board, there was a load of brown crap all over the place (dried flux I believe). Now, when I try to power on the monitor, I get no degauss, no HV, and no heater voltage. The power light turns green and starts blinking. I'm positive I got all the wires hooked up right.

Help? I knocked a SMT resistor off the board by accident, the value was 0.01MF, 50V. Surface Mount pisses me off, that thing was smaller than a crumb. I was unable to get it back on, then I lost it, so I bridged the two connections with solder. Could that be it? This was on the neck board.

That surface mount part is actually a capacitor rated at .01 uF @50 volts. You can replace it with a standard .01 uf cap rated with a voltage rating of at least 50 volts. When you bridged the connection, that created a short that could very well be causing your new problem. Maybe you'll get lucky and it didn't take anything else with it.

You're not the only one that gets PO'd at SMT devices. A great deal of consumer electronics is 95% (or more) SMT. The only economical way for repair is a new board. I recently repaired a newer JVC TV that had two open SMD resistors on the neck board. These resistors were, IMHO, too small for their task. I just took two through hole standard resistors and tacked them to the PC board and it worked fine. IMHO, SMT technology has no place in high voltage, high current, or high temperature applications.

[karmaman]

aargh!

The capacitor was indeed making the monitor act funky. I replaced it with a normal through-board one and the monitor now degausses and I get HV. BUT that was not the problem. It's now doing the same thing it was before: degausses, then the power light starts blinking yellow (because horizontal collapsed). I feel like crying (metaphorically, not literally). I replaced 6 caps in there, 3 were borderline and 3 were way off the correct readings. One was bad on the neck board, two were bad on the chassis, two more on the chassis were borderline, and one on the neck board was borderline. These are all quality caps too, there were mostly Rubycons and Nichicons in there. Nothing looks burnt or damaged in there, trust me I looked. I've become quite familiar with this monitor (literally spent all weekend working on it). I still haven't checked ALL the caps in there, probably half maybe. All HV caps (there were only 3 brown caps in there) checked out fine. So did the huge filter cap.

Q902 and Q901, both are three pin devices on a heatsink, don't look burnt or damaged in any way. Should I rule these out, or could they be bad anyway?

I will try and test the rest of the caps in there today. Any suggestions? You guys are my only hope. I really don't want to pitch this monitor, I really like it and it's got dual inputs, one VGA in the front. It comes in handy all the time because my friend regularly brings his Xbox 360 over and we play on xbox live. I doubt I'll find another computer monitor with a front input, let alone one that's also a Trinitron.

[MRX37]

Like I said before: Don't give up.

Bad caps alone won't cause the horizontal to fail to my knowledge. it's usually a bad cap that makes whatever controls the horizontal fail.

You're also lucky to actually have access to a FREE service manual. Most times you don't get that lucky.

If you're getting frustrated, stop working on the monitor for a day or two.

If you can find replacements, it wouldn't hurt to replace Q901 and Q902. Replacing them won't hurt anything as long as they're replaced with the same part, and at the very least, you can rule them out.

[karmaman]

Hey guys, there's a pretty big transistor, Q505, that shares a heatsink with Q901 and Q902. According to my multimeter it is shorted, now I haven't taken it off the PCB to test for sure, but every other transistor gave me correct readings without taking it off the PCB (won't have time to fully test it until tomorrow). According to the schematic, Q505 is responsible for H OUT. I'm very hopeful that this is the problem. Fixing this monitor has engulfed me for the last 5 days, it's all I do with my spare time, and I have finals this week :/ probably not very good to be working on a monitor instead of studying. Anyway, if Q505 IS shorted, and it's responsible for H OUT, it would probably be causing the problems I am having right now, amirite?

EDIT: According to the service manual, Q505 is a 2SC5530-01, a Hitachi part. There is no NTE cross for it. I know for a fact Radio Shack won't have it (they never have anything) and I don't think Fry's has it either. Can you guys recommend a replacement that will work? It is a Bipolar NPN transistor, not sure of voltages or anything. I also have a 15" Trinitron in the attic, any chances it might have the same part and I can pull it off there? Will check tomorrow and let you guys know. I'm feeling hopeful right now! There's no way I can pitch this monitor now, I've put about $14 worth of new capacitors in it!

BTW MRX37, thanks a million for the link to the repair manual. Without that, I would have pitched it by now.

[MRX37]

Originally Posted by karmaman

Hey guys, there's a pretty big transistor, Q505, that shares a heatsink with Q901 and Q902. According to my multimeter it is shorted, now I haven't taken it off the PCB to test for sure, but every other transistor gave me correct readings without taking it off the PCB (won't have time to fully test it until tomorrow). According to the schematic, Q505 is responsible for H OUT. I'm very hopeful that this is the problem. Fixing this monitor has engulfed me for the last 5 days, it's all I do with my spare time, and I have finals this week :/ probably not very good to be working on a monitor instead of studying. Anyway, if Q505 IS shorted, and it's responsible for H OUT, it would probably be causing the problems I am having right now, amirite?

EDIT: According to the service manual, Q505 is a 2SC5530-01, a Hitachi part. There is no NTE cross for it. I know for a fact Radio Shack won't have it (they never have anything) and I don't think Fry's has it either. Can you guys recommend a replacement that will work? It is a Bipolar NPN transistor, not sure of voltages or anything. I also have a 15" Trinitron in the attic, any chances it might have the same part and I can pull it off there? Will check tomorrow and let you guys know. I'm feeling hopeful right now! There's no way I can pitch this monitor now, I've put about $14 worth of new capacitors in it!

BTW MRX37, thanks a million for the link to the repair manual. Without that, I would have pitched it by now.

Q505 sounds like it's VERY likely to be your problem.

Input the part number into google and see if you can order it online.

The 15" trinitron is unlikely to have that specific transistor in it. It might, but don't get your hopes up.

If you can get a replacement, test the resistors and caps around that transistor. It's likely that a bad resistior or cap made the transistor fail, and you wouldn't want to put in a new one just to watch it fail 5 minutes after you power the monitor up.

EDIT: you're welcome, and I'm glad I could help.

Being the owner of a 19 inch Viewsonic flat screen CRT monitor that had intermittant HV failure when I first found it, I know fixing a monitor is not fun, but it's damn rewarding when you fix it.

EDIT 2: I think this is your part.

[karmaman]

That is indeed the part. Thanks MR37. For some reason, I was unable to find it just by googling. We're leaving on vacation in a few days and won't be back for two weeks, so sadly it'll have to wait until next year. I'm just going to try and get it out of my mind for a while, otherwise for the entire two weeks it'll be eating away at me. I will definitely order the part from bluestar if I don't find one in the 15" Trinitron (which, like you said, seems unlikely, but I will check anyway).

EDIT: I have to order at least two, bringing the total price to $10, and then the shipping is $9 (!). For something that could easily be mailed in an envelope?! There's no way my parents will let me buy this, they'll me to toss the monitor Better start searching locally, or call bluestar and see if they can take a money order so my parents won't find out how much I paid.

[MRX37]

Yeah. Leave it be for a couple weeks. Also, tell your parents that the monitor means a lot to you, hence why you've put so much time and effort into fixing it. If you're calm and offer to compromise by throwing out something else you can bear to part with, or working off the cost of the parts, they might help you out.

Best of luck to you. Hopefully you'll get it fixed, and it'll serve you well. My flatscreen's served me well, especally since the lighting in my computer room makes a non flat screen reflect light like crazy.

[radiotvnut]

When you replace the transistor, resolder all the connections around the transistor. If there is a small transformer (not the flyback) connected to this transistor, resolder that. That little transformer is the horizontal drive transformer and these were bad to have loose connections and blow the HOT in Sony TV's of the period.

I know what you mean about having to order two parts and pay $9 shipping! Most of the places I order from have at least a $25 minimum order with at least $8 shipping. I usually have to order more than I really need just to get one $4 part! The good thing is that you'll have a spare in case the first one blows or if you need another one later.

Anyway, do well on those exams and have a Merry Christmas and a safe vacation!

[radiotvnut]

Originally Posted by karmaman

The main problem I'm having right now is that the monitor lost Horizontal. I was using it earlier today when the screen kinda flinched a few times and then it turned into a very bright, vertical line going down the middle. I said a few choice words, then instantly hit the power button to avoid burn-in. Can you guys tell me what causes a loss of Horizontal, and where to start/what to check? I really want to get this monitor going again. When I turn on the monitor, it degausses and then the power light starts blinking yellow.

After re-reading everything, I'd be willing to bet the horizontal drive transformer has loose connections that caused the picture to flinch and then collapse to a vertical line and then blow the HOT. Like I said before, this was a very common problem on Sony TV's. Look on the schematic and trace the base pin of the horizontal output transformer back to a coil winding. That will be the secondary winding of the horizontal driver transformer. Resolder it's connections even if they look good.

If that IC on the neckboard is mounted on a heatsink, resolder it. Those get hot and are also bad about having loose connections.

[karmaman]

Will do. Thanks Radiotvnut, Merry Christmas to you too! I'm leaving this monitor alone until I come back. Just looking at the chassis gives me a headache.

Someone else on another forum (not nearly as good as this one) said the HOT probably blew because of bad soldering on the Horizontal Drive transformer and/or a shorted FET near the HOT. Radiotvnut, you said bad soldering on the H Drive was typical in Sony TV's of this era. I forgot to mention this is monitor was manufactured December 1999. Don't know if that helps. Anyway, I will check that out when I get back, I'm printing all this and leaving is on my desk so I'll know where I left off when I get back.


Merry Christmas everyone, talk to you next year.

[karmaman]

Hey everyone, thought I'd do a followup on this.

After some heated arguments, I ended up giving the Trinitron to a friend who's going to fix it once he gets enough $$$. My dad told me to toss it when he found out it would take $20 to get a part that isn't even guaranteed to solve the problem (someone on another forum told me there might be a shorted FET on there too).

I got a 19" LG Flatron LCD. So far, I've been loving it. The clarity is astounding, the brightness is great, and the colors are pretty good. Sometimes I miss my Trinitron for it's black levels and viewing angles, but overall I much prefer my new LG over the Trinitron. I was pleasantly surprised to find out that LCD's are crisp and sharp beyond my wildest dreams, something I didn't anticipate when I grudgingly accepted that I would have to get an LCD. I swear, most CRT monitors looks kinda blurry to me now. I guess I was just too stubborn on sticking with CRT's for computer monitors. Nothing will ever beat them for TV though.

BTW, if anyone on here has a high rez (>1280x1024) LCD and is running it on VGA, please do yourself a favor and get a DVI cable. My new LG runs at 1440x900 and when running on VGA, things look kinda fuzzy and shadowy and just not that great. With DVI, the clarity is second to none and the colors are more vibrant. The difference was so huge, even my mom noticed it from across the room as she walked in after I got a DVI cable.