HP w1907 monitor blown(no power at all)

[lipyphil]

I recently moved to a new appartment and I connected my monitor directly to the AC supply on the wall(Totally forgot to use surge protector). the monitor blew immediately and turned off. There was sound and burning smell. I read few things on here so i decided to open up the monitor and checked the caps but all the caps looked fine. I have bought a new monitor because the blown monitor is already old. I want to fix the monitor on my own so i can learn something about electronics before i go back to school for electronics. Am switching my major from the boring biology to electronics. Since am a beginner please where do i start from to fix the monitor. Thank you very much for any help. Please be easy on my questions since am starting.

[retiredcaps]

Re: HP w1907 monitor blown(no power at all)

You will need a multimeter to check the following:

1) fuse - a good fuse should measure less than 1.0 ohms
2) bridge rectifier - see if it it shorted
3) power mosfet - see if it is shorted

I have written procedures for 2 and 3 above in prior posts.

[lipyphil]

Re: HP w1907 monitor blown(no power at all)

thanks retirecaps. Can you please recommend a good multimeter to me?

[retiredcaps]

Re: HP w1907 monitor blown(no power at all)

Can you please recommend a good multimeter to me?

What is your budget for a multimeter? If it is around $100 and want a Fluke, I just wrote this last night.

https://www.badcaps.net/forum/showpo...1&postcount=66

If your budget is otherwise and want a new one, I can make other suggestions.

[lipyphil]

Re: HP w1907 monitor blown(no power at all)

My budget is around $100 to $150 and i want with esr. Does it mean i dont need a different esr meter for caps?

[retiredcaps]

Re: HP w1907 monitor blown(no power at all)

My budget is around $100 to $150 and i want with esr. Does it mean i dont need a different esr meter for caps?

1) No multimeter can measure ESR. For that you need a standalone specialized ESR meter.

2) You can spend $100 for a multimeter and $50 for an ESR meter. For the ESR meter, there have been several discussions in the "Test Equipment Usage, Techniques, and Reviews forum"

https://www.badcaps.net/forum/forumdisplay.php?f=33

3) Dave Jones at eevblog.com has done a $100 multimeter shootout. It is a bit dated, but still gives you an idea on what to look for.

http://www.eevblog.com/2010/07/11/ee...i-t-part-1of2/

http://www.eevblog.com/2010/07/11/ee...i-t-part-2of2/

4) His site also has a ton of multimeter reviews.

5) Another alternative is to get two $50 multimeters because you may need to measure current and voltage at the same time. Dave's $50 shootout.

http://www.eevblog.com/2010/06/04/ee...eter-shootout/

6) Dave's multimeter buyer's guide.

http://www.eevblog.com/2010/04/14/ee...-buying-guide/

7) Again, ebay is a viable option for used multimeters, but obviously caveat emptor. Every multimeter I have at home is used.

[lipyphil]

Re: HP w1907 monitor blown(no power at all)

I went through most of the links and they seem little confusing. Ok i decided to buy two $50 multimeters but they are not true rms. Does it matter for am trying to do? I have decided on the extech ex330. Will the ex330 be ok for my purpose. Thanks

[retiredcaps]

Re: HP w1907 monitor blown(no power at all)

The $100 shootout reminded me of this current ebay deal. I don't have affiliation with the seller (gilco4020) or financial gain from this recommendation. I tried to buy this exact multimeter from the seller, but they have it setup not to even receive emails from non USA members.

http://www.ebay.com/sch/i.html?_from...4XR+Multimeter

The Meterman 34XR sells for $170 CDN at the local electronics store.

On ebay, you can EASILY get it (+ probes) for $10 as there is often only 1 bidder or no bidders. I suspect the seller bought surplus government multimeters and the government is undergoing a refresh cycle.

So for $10 + $15 shipping, you can get a true RMS multimeter. My first multimeter was a Meterman 15XP and it works great. If the seller would ship to Canada, I would have one or two of them.

In the shootout, Dave didn't like its

a) slow continuity speed
b) sound of the beeper ("it makes my stomach churn")
c) uA and A jack a bit loose

The slow continuity speed could be an issue if you needed to find a short in a circuit and had a lot of things to probe. Otherwise, I don't think it is a negative for your first multimeter.

On the plus side, you get

a) true RMS
b) ability to measure capacitance up to 4000uF (more than enough for TV/lcd troubleshooting), but NOT ESR
c) name brand company
d) micro and milli amps (good for electronics)
e) temperature
f) frequency
g) ruggedness (it won't die when you drop it)
h) backlight
i) generally good quality probes
j) min/max
k) $10!!!!! (get 2)
l) $10!!!

Just put in a bid for $12.12 and you should win it for that or less.

True RMS may be required in your future school studies so it would be good to get.

PS. True RMS

http://en.wikipedia.org/wiki/True_RMS_converter

[lipyphil]

Re: HP w1907 monitor blown(no power at all)

thanks i put in a bid and am waiting if i will win. hope i do.

[retiredcaps]

Re: HP w1907 monitor blown(no power at all)

thanks i put in a bid and am waiting if i will win. hope i do.

Congratulations. You won. I'm super jealous. Like I said, if the seller would ship to Canada, I would have a more than one.

You won't find another True RMS multimeter for $10 from a name brand company.

BTW, the probes in the auction look like Fluke TL71 probes. If I'm correct, they sell for $25 brand new. They are nice probes made out of silicon and have a nice feel in the hands.

[lipyphil]

Re: HP w1907 monitor blown(no power at all)

I can't wait to see my first meter haha. BTW how do i find your post on
1) fuse - a good fuse should measure less than 1.0 ohms
2) bridge rectifier - see if it it shorted
3) power mosfet - see if it is shorted

[retiredcaps]

Re: HP w1907 monitor blown(no power at all)

I can't wait to see my first meter haha. BTW how do i find your post on
1) fuse - a good fuse should measure less than 1.0 ohms
2) bridge rectifier - see if it it shorted
3) power mosfet - see if it is shorted

Search function.

[lipyphil]

Re: HP w1907 monitor blown(no power at all)

I got the meterman but there is no croc or aligator clip so i have orederd one. I have already taken out the main fuse close to where the AC plugs into the board but i was unable to test it with just the test leads without clips. And i have also ordered the blue esr. So I am still waiting to gather my tools. Am i right to check resistance of the fuse out of circuit?

[retiredcaps]

Re: HP w1907 monitor blown(no power at all)

Am i right to check resistance of the fuse out of circuit?

For fuses you can test them in circuit and get an accurate reading. It is one of the few things that you can accurately measure resistance "in circuit".

PS. You don't need clips do any of the resistance measurements. Clips are useful if you are measuring on the hotside as voltages can be as high as 400V DC. Clips reduce the likelihood of you getting hurt on the hot side, but it doesn't replace knowledge and common sense.

[lipyphil]

Re: HP w1907 monitor blown(no power at all)

I measured two fuses, F801 which is close to the AC source and F802. Both FB01 and F802 measures 0.4ohms so thinking the fuses are ok. Are there anymore fuses am missing on the board that needs to be checked?? I am yet to check on the mosfet. Can you please show me which ones are/is the mosfet? I am thinking is the three pin thing on the heatsink. I have posted pictures of my board.

[Jasgriff]

Re: HP w1907 monitor blown(no power at all)

Cant see the pictures of your board as of yet.

Here is a link to the service manual for your monitor too.

http://www.eserviceinfo.com/download...HP_wf1907.html

[lipyphil]

Re: HP w1907 monitor blown(no power at all)

Try uploading pictures but failed. Keep getting this message:

Your submission could not be processed because a security token was missing.

If this occurred unexpectedly, please inform the administrator and describe the action you performed before you received this error.

[Jasgriff]

Re: HP w1907 monitor blown(no power at all)

What size are they?

[lipyphil]

Re: HP w1907 monitor blown(no power at all)

Range from 1.21mb to 1.47mb each and there are about 5 images

[retiredcaps]

Re: HP w1907 monitor blown(no power at all)

Range from 1.21mb to 1.47mb each and there are about 5 images

See post #2. Follow the instructions EXACTLY.