Sceptre X9G-Komodo II* blinking power light

[hennegan]

Re: Sceptre X9G-Komodo II* blinking power light

Thank you Jetadm123! I guess symptoms would help--can't believe I neglected to post those too.

When the screen is powered on with a signal (VGA or DVI), The screen displays for a half second, then goes black. The power LED remains on after the panel goes black. If the screen is turned off/on, the screen comes on again for a half second. I don't believe it is [just?] the CCFLs, as I can see nothing on the panel under a bright light source when on. When this first started, I found that if I power-cycled it enough, it would eventually stay on as long as my PC never turned off the displays. This worked for days at a time until I could get a good used 5:4 ratio 19" replacement.

No blinking power light though; I still posted here though because I'm guessing the problem roots around the same LM004 power board all these LCDs share.

The first thing I checked was fuse F1, hoping it was something simple. Good continuity there though.

Will check connectors and filter cap voltage and report back, though may take a week or so.

[jetadm123]

Re: Sceptre X9G-Komodo II* blinking power light

Thank you RetiredCaps. My apologies for hastily jumping in with nothing to work from.

Some starter pics attached. These were re-sized from 3000x2000 (Nikon D80), so please let me know if larger samples would help.

The large cap has some leakage around one post. It reads "PS(M)105°C (C)04052"

On a side note, I thought it would be worth a shot to e-mail Sceptre directly to inquire about a replacement part. The replied "...we will need a serial number off the power board. It should start with 3404...or 3405.... It is printed on a barcode sticker." I can see no such thing.

Also, I have an identical working model of this LCD. I'm tempted to dismantle it to see if it has any identifications this one does not. Lastly, for full disclosure's sake, I believe I have sent both of these screens in for repair once during their lifetime (I didn't investigate much, but probably for the same problem here). Almost as frustrating as the few dozen Dell Optiplex GX270s I had to fix after their capacitor fiasco. I don't think I'll ever go Sceptre again, but if this can be fixed for less than their steep repair price, it's worth the adventure.

Welcome to the forum! Can you please give us a description of what the trouble is? Is the power led flashing? No picture? Flash of light, then black screen?

One of the first things to do is check for output voltages. Assuming you're in the USA, the voltage across the main filter cap should be approx: 165VDC

Generally, you have outputs of 5V for the logic card and LCD panel and 12V for the inverter circuit. Hard to tell from the photos if the circuit board connectors are silk screened with the voltage values. Make sure everything is hooked up before you measure for these values. Also check fuse F1.

[hennegan]

Re: Sceptre X9G-Komodo II* blinking power light

Thank you RetiredCaps. My apologies for hastily jumping in with nothing to work from.

Some starter pics attached. These were re-sized from 3000x2000 (Nikon D80), so please let me know if larger samples would help.

The large cap has some leakage around one post. It reads "PS(M)105°C (C)04052"

On a side note, I thought it would be worth a shot to e-mail Sceptre directly to inquire about a replacement part. The replied "...we will need a serial number off the power board. It should start with 3404...or 3405.... It is printed on a barcode sticker." I can see no such thing.

Also, I have an identical working model of this LCD. I'm tempted to dismantle it to see if it has any identifications this one does not. Lastly, for full disclosure's sake, I believe I have sent both of these screens in for repair once during their lifetime (I didn't investigate much, but probably for the same problem here). Almost as frustrating as the few dozen Dell Optiplex GX270s I had to fix after their capacitor fiasco. I don't think I'll ever go Sceptre again, but if this can be fixed for less than their steep repair price, it's worth the adventure.

[retiredcaps]

Re: Sceptre X9G-Komodo II* blinking power light

I'm tempted to just start with the big cap on the board (the only one i can *see* is damaged), then going from there.

A pic of the big cap would be interesting to see.

Post clear focused pictures AFTER reading

https://www.badcaps.net/forum/showthread.php?t=1868

Please do not post pictures inline.

Take your boards to a window on a sunny day, turn flash off, and use macro mode. Take a top down view of all your boards (front and back). Make sure the photo is legible so that we can read the PCB printing clearly. A shutter speed of 1/125 or faster will produce nice clear focus pictures. Try to get a photo that is 2000x2000 resolution or as close as possible.

Here is an example of the pictures we want.

https://www.badcaps.net/forum/showpos...94&postcount=1

[hennegan]

Re: Sceptre X9G-Komodo II* blinking power light

I have replaced all caps,resolder all bad/suspect solder joints, and replaced Q6 and Q7 with similar ones, after that monitor works. After I removed Q6 form board I tested it and it was shorten. Q7 was ok, but I replaced it just in case.

Mistery, congrats on the fix!
I have the same problem with my LM004 board, and this will be my first attempt at a circuit board repair. Would you be able to list all the parts you replaced? I'm having trouble tracing the various paths this thread has taken. I'm tempted to just start with the big cap on the board (the only one i can *see* is damaged), then going from there.

Hello to all! I think I'll be keeping this thread alive for the next few weeks until I fix this thing, or destroy it while trying.

-Will

[mistery]

Re: Sceptre X9G-Komodo II* blinking power light

I have replaced all caps,resolder all bad/suspect solder joints, and replaced Q6 and Q7 with similar ones, after that monitor works. After I removed Q6 form board I tested it and it was shorten. Q7 was ok, but I replaced it just in case.

[alexanna]

Re: Sceptre X9G-Komodo II* blinking power light

Well I am going to have to replace a diode I dammaged lifting it up to measure
here is a pitcure of it. the marking on it are s4 3b.
if i could find the spec i would use an axiel lead if need be.
Any ideas?
Al.

Well this is getting intresting.I have found a replacement for the diode I damaged
I have replaced the poly cap on the effected circuit and changed positions of the inverter coils,Replaced
Q6 and Q7 and they continue to short .
Measuring the two circuits there was a difference in the voltage drop of the zener diodes I felt I should try to replace zd1. Well the Q6 and Q7 are no longer failing but-----
I have no idea what happened but some how the over and or under voltage protection has been disabled the 2 ccfls at the bottom of the board light up an stay on and the top ccfls are not working.
There is a TL1451a controller used in this circuit similar to some of the benq boards.
I am open to suggestions on what else I should check
Al

[hoadle]

Re: Sceptre X9G-Komodo II* blinking power light

I had Sceptre X9G Komodo IV same problem, when monitor had power the powerlight blinking about 5min & monitor turn on ok long the had 110 VAC hook up the monitor, if I'm disconnect power had go same steps above again
I open can't find any caps bad but replace all but still same problem (maybe some transitor bad?)
any one know how to fix this problem?
Thanks

Finally find cold solder at 2 pins on quickdiconnection to VGA card, resolder is working final
Thanks for all you help me out

[retiredcaps]

Re: Sceptre X9G-Komodo II* blinking power light

wow that helps

I wonder how we will id components in the future when they get so small that there is no room for writing or color bands on them. Especially when some manufacturers seem loathe to publish schematics.

[alexanna]

Re: Sceptre X9G-Komodo II* blinking power light

I had Sceptre X9G Komodo IV same problem, when monitor had power the powerlight blinking about 5min & monitor turn on ok long the had 110 VAC hook up the monitor, if I'm disconnect power had go same steps above again
I open can't find any caps bad but replace all but still same problem (maybe some transitor bad?)
any one know how to fix this problem?
Thanks

There is another thred going now DCLCD19".
With a blinking pled .To me these look the same.You might whant to follow it
If your board is the same
Al.

[alexanna]

Re: Sceptre X9G-Komodo II* blinking power light

Try the smd codebook?

http://www.marsport.org.uk/smd/codeintro.htm

wow that helps ,Thanks.
I stoped by or local electronic supply here, Gateway electronics ,Before I read your poast and they thought it might be a high speed schotty.
Looks like the site you suggested conferms it.
I will keep everyone informed of what happens
Thanks again Al

[retiredcaps]

Re: Sceptre X9G-Komodo II* blinking power light

I had Sceptre X9G Komodo IV same problem, when monitor had power the powerlight blinking about 5min & monitor turn on ok long the had 110 VAC hook up the monitor, if I'm disconnect power had go same steps above again

Clear focused pictures of all your boards (top down, both sides) would help. Post after reading

https://www.badcaps.net/forum/showthread.php?t=1868

Check for bad/suspect solder joints. As the monitor warms up, the solder joints could move around and finally make contact so that the monitor works.

edit: And if the IV is significantly different from the II, start a new thread so we can keep track of things. It would be too confusing to have 2 different monitors in one thread.

[retiredcaps]

Re: Sceptre X9G-Komodo II* blinking power light

the marking on it are s4 3b.

Try the smd codebook?

http://www.marsport.org.uk/smd/codeintro.htm

[hoadle]

Re: Sceptre X9G-Komodo II* blinking power light

I had Sceptre X9G Komodo IV same problem, when monitor had power the powerlight blinking about 5min & monitor turn on ok long the had 110 VAC hook up the monitor, if I'm disconnect power had go same steps above again
I open can't find any caps bad but replace all but still same problem (maybe some transitor bad?)
any one know how to fix this problem?
Thanks

[alexanna]

Re: Sceptre X9G-Komodo II* blinking power light

Well I am going to have to replace a diode I dammaged lifting it up to measure
here is a pitcure of it. the marking on it are s4 3b.
if i could find the spec i would use an axiel lead if need be.
Any ideas?
Al.

[jetadm123]

Re: Sceptre X9G-Komodo II* blinking power light

Sure, it's a possibility that the cap is still bad. The only way to find out is to replace it. Others may have a different approach to this problem and may be able to provide additional testing/insight that I may have overlooked.

As for D1, I suggest you contact Bstock72, since he is the originator of this thread and has a board identical to yours and can provide more accurate info on D1.

[alexanna]

Re: Sceptre X9G-Komodo II* blinking power light

jetadm 123 Thanks for the reply.
the poly cap is measuring 101nf ,Can a poly cap fail and still be within spec?
also in some of my testing I have damaged D1 markings on it are s4 3b any ideas on a replacement for it?
Al.

[jetadm123]

Re: Sceptre X9G-Komodo II* blinking power light

The grey poly cap has markings on it
.1 and 250
and it is conected to the center thrminals of 2sc4672, Q6 and Q7

Okay, from the 2SC4672 spec sheet, it looks like the center lead is for the collector terminal. The center lead of Q6 and Q7 should each also be connected to a leg of the inverter transformer (please verify this). If correct, this inverter circuit is somewhat similar to some viewsonics and dells (as PlainBill mentioned in POST #9). Now, since the poly cap is connected across both collectors and rated at 250 volts, I'm thinking it might be used for voltage transient/noise suppression from the transformer. If this cap has failed, then it might be allowing excess voltage to reach Q6 and Q7 (2SC4672 is rated @ 50V), thus shorting them out. Make sense? Anyone else feel free to chime in.

[alexanna]

Re: Sceptre X9G-Komodo II* blinking power light

Hello! Can you please provide the capacitance value and voltage of the grey polycap. And can you verify if this polycap is across the collector leads of Q6 and Q7. Thanks!

The grey poly cap has markings on it
.1 and 250
and it is conected to the center thrminals of 2sc4672, Q6 and Q7

[jetadm123]

Re: Sceptre X9G-Komodo II* blinking power light

This monitor Gives a very brief flash of the back lamps on power up.the desktop is there after back lamps go out.
Q6 and 7 showed a short between pins.These have been replaced,
With a single ccfl hooked up one at a time there is a normal 2sec bright flash of the lamps on the two ccfl connectors at the bottom of the board near the A.C. plug.On the top of the board the conector near the edge of the board there is a very brief dim flash. And at that point q6 and 7 show shorted again
On my initial visual inspection of the board the area of C10, the grey polycap and L1 had bad solder joints,I have removed measured these, along with the T1 coil,And comparied the readings to the out of circuit readings of T2 L2 and C21 These readings are almost exactly the same.These have been resolderd back into the board.
I have replaced the two caps for the inverter section. c2 was replaced with a panisonic fm series.Due to a mix up [capacitors packaged wrong ]I had to use a nichion audio grade cap for testing proposes for c4.The correct part is on the way.
I need to have some help figuring out why Q6anQ7 are faling?
Al.

Hello! Can you please provide the capacitance value and voltage of the grey polycap. And can you verify if this polycap is across the collector leads of Q6 and Q7. Thanks!