NEC Multisync 1830 XtraView - Dead inverter

[Scenic]

Re: NEC Multisync 1830 XtraView - Dead inverter

i fixed a lot of LCDs with "universal" inverters from ebay seller "KITSPART888"...

http://search.stores.ebay.com/KITSPA...274847QQsofpZ0

but its only useful if
- you can fit the inverter into your LCD (not always the case..esp. with the 4lamp one)
- the LCD is working fine otherwise

.. because its rather expensive.. so no go for let's say old 15" LCDs or so..

edit: replace the "Chang" caps if you're going to use one of those

[Toasty]

Re: NEC Multisync 1830 XtraView - Dead inverter

Just an inquiry to see if this ever was resolved or tested as I asked back in Post #8. Any resolution or conclusions?

[EGuevarae]

Re: NEC Multisync 1830 XtraView - Dead inverter

The most likely reason that the transistors(Q's) and caps are reading 0 (zero) ohms is that they are across the transformer coils. Tough to short those caps as they (from what I've read) are the ceramic chip type and in the in the picofarad range. (1uf = 1,000,000pF)

Also, try reversing the probes of your ohmmeter when you test a suspected component. Many meters present enough voltage/current when testing on the low ohms setting to forward bias (turn on) diodes and transistors. You get a reading one way, but when you reverse the probes, you get nothing or a different reading than the first one.

Are the fuses good?

If you power it up, does one transformer get warm and the other stays cold?

Toast

- Fuses Good.
- Probes reversed, same reading. Tried 3 different MM (even one Analog). Nothing
- The transformers are cold as ice. I tested the AC output of the "good side" of the inverter (between 500~600V as far as I remember), but the inverter shuts down so fast (1~2 secs at most) that I guess they have no time to get hot. None of them gets hot or varies the temp.
- Ordered a Universal 4 CCFLs inverter ($15 shipped) to test this, an X2Gen 17", a ToteVision 18" and my now defunct 172N 17"from another thread (the one with 3 10k Ohms resistors burned) that was found to have continuity - yes, I ran to the the ohmmeter - between the two sides, tested off board (while the other, tested off board too, does not).

I was messing with them like an hour ago. I can't beat them!!!!

[Toasty]

Re: NEC Multisync 1830 XtraView - Dead inverter

Try this again... quick post didn't work.

-Same as 172N - do the XFMR resistance checks

-voltage reading at cap ?? 12v ??

-bit about the 172N should have been posted in its forum, not here. I'd have seen it and not bothered with the circuit tracing pics.

[EGuevarae]

Re: NEC Multisync 1830 XtraView - Dead inverter

Try this again... quick post didn't work.

-Same as 172N - do the XFMR resistance checks

-voltage reading at cap ?? 12v ??

-bit about the 172N should have been posted in its forum, not here. I'd have seen it and not bothered with the circuit tracing pics.

????

[EGuevarae]

Re: NEC Multisync 1830 XtraView - Dead inverter

I'd have seen it and not bothered with the circuit tracing pics.

? Please can you explain?
I followed the traces, uploaded a better picture, and have answered all your questions as far and as good as I am able to. I am really interested (and grateful) in your interest and time (and in the other members' too), and even have a printout of your traces next to the place where the board is. I don't get it....

[Toasty]

Re: NEC Multisync 1830 XtraView - Dead inverter

Whoa! WTH?

This topic is about the NEC Multisync 1830. Not the 172N.

Your bit 3 posts ago -

...and my now defunct 172N 17" from another thread (the one with 3 10k Ohms resistors burned) that was found to have continuity - yes, I ran to the the ohmmeter...between the two sides, tested off board (while the other, tested off board too, does not)...

That response is for the 172N topic, not this one. I'm just saying that had I seen that on the 172N thread, I would not have bothered with the tracing, as that reveals the 172N transformer was bad.

Important to post in topic as well as on topic .

Now my questions for the NEC Multisync 1830 are:

1) Have you done the XFMR checks on the 1830 like you did to the 173N - out of circuit?

2) What voltage are you getting at the cap? Any? It's marked 16v but probably only receiving 12v or less.

[EGuevarae]

Re: NEC Multisync 1830 XtraView - Dead inverter

Whoa! WTH?

This topic is about the NEC Multisync 1830. Not the 172N.

Your bit 3 posts ago - That response is for the 172N topic, not this one. I'm just saying that had I seen that on the 172N thread, I would not have bothered with the tracing, as that reveals the 172N transformer was bad.

Important to post in topic as well as on topic .

I was referring to the NEC, and said that I ordered ONE universal inverter to test FOUR (mostly, to see if it fits and what has to be done to fit them) LCDs. And I mentioned the 172N because I was messing with them all and after that I posted the reply. I'm not mixing the posts, it was just a comment saying that I can't beat that 4 damn LCDs.... YET

1) Have you done the XFMR checks on the 1830 like you did to the 173N - out of circuit?

Not yet. Messing with wife's computer at the moment, but it has been noted in the "SHIT TO DO" list. Will post results as soon as I can.

2) What voltage are you getting at the cap? Any? It's marked 16v but probably only receiving 12v or less.

They receive 12v (12.03v to be exact). They are rated at 16v.

[EGuevarae]

Re: NEC Multisync 1830 XtraView - Dead inverter

1) Have you done the XFMR checks on the 1830 like you did to the 173N - out of circuit?

I desoldered the two transformers and tested them off circuit.

top part has 4 pins (not visible), and bottom has 5.
Naming top pins A..D, and numbering bottom 1..5, this is what I got:

• On the primary, there's continuity between 1 & 5.They do not cross any other pin on either this side or the other (secondary) side.
• Pins 2,3 & 4 have continuity also between them, but not with any other on either side.
• Between B & D there's no connection,either between them or with anything. They are "orphan".
• Between A & C there's connection,with a resistance of 354 Ohms, between them, but not to any other pin.

Conclusions :

• 1/5 & 2/3/4 are the transformer input on the primary, and A & C the output on the secondary.
• The transformers are not shorted (the two have the same readings).

It is correct my list of conclusions?

Also, the transformer(s) is/are not the same as the 172N ones, so they can't be used there......
And finally, C11 & C12, the caps I said were shorted, are , as you said, across transformer contacts (2 & 4 in this case)

[Wizard]

Re: NEC Multisync 1830 XtraView - Dead inverter

These two transformers are same, if readings differs, one of them is bad.

Cheers, Wizard

[EGuevarae]

Re: NEC Multisync 1830 XtraView - Dead inverter

These two transformers are same, if readings differs, one of them is bad.

Cheers, Wizard

Same reading on both Ts.
But I have another question.
Using this chematic , I traced the 12.29v that get to the inverter up to this IC, labeled 5102. It is a 8 pin (4/4) Ic. I can't find a datasheet for it (I only found 10 pins versions and I don't know if it is the same).
Here is a section of the schematic showing only the IC and its surrounding components.


This is the internal schematic/diagram of the IC in question, according to the schematic:

There's Voltage reaching pins 1~3.I tested with an ohmeter, and there is no resistance between them, as the picture suggests.
12v reach pin 4 too, but come from another source (Q2 output).
BUT NOTHING COMES OUT OF 5~8. No voltage reaches L1, so no voltage reaches the Transformer(s) and no backlights.
May I conclude that the IC is bad because there's no output?
That is a MOSFET but with 8 pins instead of 3 (1~3 - 1st Pin, 4=2nd pin, and 5~8=3rd pin).
Also, in case this is damaged, where can I find a replacement if I can't find a datasheet? The last pic is of the IC under suspicion. It has only 5102 , and two more characters that I cant see if they are DL, 01, or something like that.

[Toasty]

Re: NEC Multisync 1830 XtraView - Dead inverter

Check transistors Q2, Q10, and diode D1 with ohmmeter.

Conclusion correct. Transformers match and are fine.

>>May I conclude that the IC is bad because there's no output?<<
No. You can only conclude there is no output.

After (if) transistors and diode check out, then hook it back together with tubes in place. Turn it on and with DMM give me voltages ACROSS the following resistors:
R1 (-) probe to R1-R2 junction
R2 (-) probe to R1-R2-Q5 collector junction
R31 (-) probe to Q10 emitter
R32 (-) probe to Ground (+) to Q10 collector

[NxB]

Re: NEC Multisync 1830 XtraView - Dead inverter

Its one of those mosfets like on motherboards maybe. Like one of these:

http://www.st.com/stonline/products/...sts4c3f30l.htm

[EGuevarae]

Re: NEC Multisync 1830 XtraView - Dead inverter

Check transistors Q2, Q10, and diode D1 with ohmmeter.

Conclusion correct. Transformers match and are fine.

>>May I conclude that the IC is bad because there's no output?<<
No. You can only conclude there is no output.

After (if) transistors and diode check out, then hook it back together with tubes in place. Turn it on and with DMM give me voltages ACROSS the following resistors:
R1 (-) probe to R1-R2 junction
R2 (-) probe to R1-R2-Q5 collector junction
R31 (-) probe to Q10 emitter
R32 (-) probe to Ground (+) to Q10 collector

You sound like me when I was teaching Delphi to a girl I left in my job when I moved here to the States.
She:"So, this database can only be modified as a flat table?"
Me:"No. Only you can modify it ONLY as a flat table. See the comments in the code I left you, and after reviewing the code and the comments, give me the SQL sentences needed to alter it using SQL server ACROSS the VPN link to Accounting"........ Karma exists. But she learned that way, and I hope I'll learn too.
I'll make that notes and post back the result of the test. But now I have another question.
So far, the transformers are ok, there's input on pins 1~3, and in pin 4 too, and all are 12v (12.29v), but no output.

[Toasty]

Re: NEC Multisync 1830 XtraView - Dead inverter

All that time typing that you could've been measuring voltages.. *sigh*




...and the question is...???

[EGuevarae]

Re: NEC Multisync 1830 XtraView - Dead inverter

All that time typing that you could've been measuring voltages.. *sigh*



...and the question is...???

I WAS measuring. Just was interrupted while posting...
The question is : if there's input, why there's no output?
I don't disagree with your conclusion that I cannot conclude it is bad, just I don't understand it. But well.....

1.- I tested the diode (off circuit). In Diode Test Mode (DMM) it shows 158 in one way and nothing the other way.
3.- As references to R1,R2,R31 & R32 I checked them to see if the values were equal to the ones specified in the schematic, and they were (R2 & R31:10K, and R2 & R32 : 2K) - Not asked for, but I was there anyway.
2.- Q2 & Q10 are too small, so I took another board with similar components and tried desoldering them and then putting them back: I can't, so the readings are IN circuit
Q10:

• E-C+ : 400 ohms
• E+C- : 400 ohms
• B+E- : 10,000 ohms
• B+C- : 20,000 ohms

Q2:

• E-C+ : 10,000 ohms
• E+C- : 400 ohms
• B+E- : 400 ohms
• B+C- : 1500 ohms

Voltages:

• Q2 has 12v in all 3 contacts (11.99~12.06)
• Q10 has 11.91v in C and 12.03v in E, and B is GND (???)
• R1,R2 & R31 had 12v. R32 has no V applied to it
• (+) on V input of the inverter and (-) on D1,I get 12v.
• (+) on V input of the inverter and (-) on 5102 pins 5~8,I get 12v.
• (+) 5102 pins 1~4 and (-) on 5102 pins 5~8,I get 12v.
• (-) Probe on R2, I get -12v on Q5 C & E & R31 had 12v. R32 has no V applied to it

Between Q10 base and GND there's no resistance (or too low to measure).
I tried to do what you asked, just remember I'm a software developer, not an EE, and I'm trying to keep up with you guys....
And as for the 5 inverters lot you saw on eBay, the lady has like 70~80 dead inverters, so maybe I'll invest $20 on getting 5 of those, or I can invest the same $20 to get a VL150 4 outputs inverter from her, adapt it and get the 1830 going.

[Toasty]

Re: NEC Multisync 1830 XtraView - Dead inverter

Okay, I am not getting through. I have to think of another way to get you to measure the voltages ACROSS the components.

The diode check looks good and the 2 transistors do too.

[EGuevarae]

Re: NEC Multisync 1830 XtraView - Dead inverter

Okay, I am not getting through. I have to think of another way to get you to measure the voltages ACROSS the components.

Just waiting for instructions. Sorry to be a PITA

[Toasty]

Re: NEC Multisync 1830 XtraView - Dead inverter

Completely back together, all hooked up, and powered on.

See the attached pic. Read voltages as shown with your DMM.

Voltages ACROSS the following resistors:

1) R1 (-) probe to R1-R2-Q5 collector junction
2) R2 (-) probe to R1-R2-Q5 collector junction
3) R31 (-) probe to Q10 emitter
4) R32 (-) probe to Ground (+) to Q10 collector

Voltages:

1 =
2 =
3 =
4 =

LMK

[EGuevarae]

Re: NEC Multisync 1830 XtraView - Dead inverter

Completely back together, all hooked up, and powered on.

See the attached pic. Read voltages as shown with your DMM.

Voltages ACROSS the following resistors:

1) R1 (-) probe to R1-R2-Q5 collector junction
2) R2 (-) probe to R1-R2-Q5 collector junction
3) R31 (-) probe to Q10 emitter
4) R32 (-) probe to Ground (+) to Q10 collector

Voltages:

1 =
2 =
3 =
4 =

LMK

I guess got the idea the first time. The problem was finding that damn junctions in the circuit : everything is so small. 1st Round was a draw cause at least I got the readings for the diode & the Qs. I want to win the 2nd.
ILYK