HannStar Monitor

[PlainBill]

Re: HannStar Monitor

PlainBill I wish I had your eyes; I can barely make out F1 on the panel
Where do you see the IC501?

The identifier is on the lower right corner of the IC. If that doesn't help you, you should have no problem identifying IC302, it's the rectangular AD chip. Move in the 2 O'Clock direction (toward Q502).

PlainBill

[alexanna]

Re: HannStar Monitor

IC501 and associated components generate the voltages required for the LCD panel. I'd suggest looking up the datasheet for the IC and checking if it is generating voltages. A common failure is the not-so-small SMD caps short out. Also, near the left edge of the same picture is a point labeled VDD+9V. I'd look for more and check the voltage is present. For the sake of convenience, you might want to hook a computer to the signal card so you can make sure the power will always stay on.

PlainBill

PlainBill I wish I had your eyes; I can barely make out F1 on the panel
Where do you see the IC501?

[PlainBill]

Re: HannStar Monitor

Well thats a real small bugger and I'm glad I don't have to change it and yes it has contenuity.

IC501 and associated components generate the voltages required for the LCD panel. I'd suggest looking up the datasheet for the IC and checking if it is generating voltages. A common failure is the not-so-small SMD caps short out. Also, near the left edge of the same picture is a point labeled VDD+9V. I'd look for more and check the voltage is present. For the sake of convenience, you might want to hook a computer to the signal card so you can make sure the power will always stay on.

PlainBill

[rigeback]

Re: HannStar Monitor

Well thats a real small bugger and I'm glad I don't have to change it and yes it has contenuity.

[PlainBill]

Re: HannStar Monitor

OK, To be certain about getting power to ICI-501 I hooked up the CCFL lamps and the T-Con board gets the 5 volts @ the ICI-501 for short burst until the video card goes into standby. So this seems to romove the power source and video card from the problem??

Correct. A quick summary of how these work: The power supply takes line voltage and converts it to 5V (for the signal card) and 12V (for the inverter). The signal card checks it's last known state. If it was On, or in Standby, it turns on the LCD panel and the inverter, then starts looking for video signal. If it doesn't see a video signal within a few seconds, it puts up a 'No Signal' message, then turns off the LCD panel and the inverter.

Take a look at the second picture you posted; it shows the panel card (or more correctly, the tcon). Look at the connector from the signal card. The left pin goes to R57. The next three pins are all tied together, and to one end of F1.

PlainBill

[rigeback]

Re: HannStar Monitor

OK, To be certain about getting power to ICI-501 I hooked up the CCFL lamps and the T-Con board gets the 5 volts @ the ICI-501 for short burst until the video card goes into standby. So this seems to romove the power source and video card from the problem??

[rigeback]

Re: HannStar Monitor

Bill, I got the video board hooked up to the T-con board but the is no power entering the T-con, the CCFL lamps are disconected. Power is entering the video board 12, 5 & 3 Volts. I found the ICI-501 with no problem but I just don't see F-1, this was the first thing I looked for but can't find it!

[PlainBill]

Re: HannStar Monitor

Bill, This tells me a lot but whats the best course of action to get this monitor running?

It may not be possible. A white screen indicates a problem with the signal card, the cable from the signal card to the panel, or the panel itself. That's the first piece of bad news.

The second is that your methodology is wrong. You've been concentrating on the power supply / inverter; that is probably NOT the problem. You have a responsive signal card - granted, all that works is the power button, but that means a major part of the signal card is working.

The third is that while you have provided good pictures, you haven't provided a picture showing the dark lines. Specifically, are they a line of frozen pixels, or are they a smudge on the screen? Both are bad, frozen pixels are probably unrepairable.

The good news is that you HAVE provided pictures of the panel card. Perhaps I have missed it; have you checked F1? Have you checked for 5V on F1 while you have a white screen? Have you checked voltages around IC501? IC501 generates the voltages required by the LCD panel.

PlainBill

[rigeback]

Re: HannStar Monitor

Bill, This tells me a lot but whats the best course of action to get this monitor running?

[PlainBill]

Re: HannStar Monitor

Thanks Bill,
I take it these transistors need to be changed out for a higher voltage like 20-25 volts to energize the video board correctly?

No.

There are a number of considerations involved in choosing a transistor for a particular application. These parameters include voltage, current, gain, frequency, power dissipation. When choosing a replacement, it's best to go with the same part number. If you must substitute, try to match the original voltage.

My point was that the specifications of the part - especially the maximum allowed voltage - will be much greater than the actual conditions. In your specific example - Gate source should -+25 Volts and the drain source 60 Volts - This means that the transistor should never be used in a design where the gate - source voltage is greater than 25 volts, nor where the drain - source voltage is greater than 60 volts. The specs say (almost) NOTHING about the voltage you expect to see in the actual circuit.

PlainBill

[rigeback]

Re: HannStar Monitor

Thanks Bill,
I take it these transistors need to be changed out for a higher voltage like 20-25 volts to energize the video board correctly?

[PlainBill]

Re: HannStar Monitor

According to the data sheet for this trasistor the Gate source should -+25 Volts and the drain source 60 Volts http://www.datasheetarchive.com/AP99...datasheet.html

Those are the MAXIMUM voltages. If you have a 12V source and are switching a non-inductive load, you would want a transistor rated for at last 12V; 25V would be better. If there is an inductive component, a higher voltage would be much better.

Something similar applies to capacitors - you want a significant overvoltage for a filter capacitor. 25 volts for a 12 volt supply would be typical.

PlainBill

[rigeback]

Re: HannStar Monitor

Okay did a powered on test of the transistors and on both I get 12.1 Volts between the D-G & D-S

[rigeback]

Re: HannStar Monitor

According to the data sheet for this trasistor the Gate source should -+25 Volts and the drain source 60 Volts http://www.datasheetarchive.com/AP99...datasheet.html

[rigeback]

Re: HannStar Monitor

Yes the transistor centre pad shows contenuity to the place where it should have been soldered.
Yes the screen is completly white when powered on although it receives the suspend and wakeup from the video card ok, I just check all the flex ribbon at the board terminals for contenuity and they are okay, the ribbon was slightly crushed.
Will have to reassembble to check the voltages!

[alexanna]

Re: HannStar Monitor

I am having a hard time seeing how on a loose flex ribbon from the T-con to the panel is causing a white screen; I have noticed what I will describe as thin colored racing stripes through the picture when ONE flex cable has loosened. If there is the problem with the bonding you will have to replace the panel.
The pink and white wires soldered to the board are probably factory; they just needed to extend the connection to the CCFLs on that half of the panel. To verify the transistors are installed correctly, check to see if the solder pad that the center tab is soldered to shows continuity to the pad where you think the middle leg would be soldered to.
From what you describe you have a predominately white screen? Is that correct?
Dose the flex ribbon cable from the signal card to the panel look damaged in any way?
Is the voltage going to the signal card good?
Dose the panel have voltage going to it?
And do you notice any common voltages on the signal card [5v-3.3v-2.5v or 1.8 volts]?

[rigeback]

Re: HannStar Monitor

Did some measuring and I only get a reading between G-D 133.6 @ 200 S-D & S-G rest 1

[killian6pk]

Re: HannStar Monitor

What I read said to identify the area of the screen in relation to the TCP and to take the aluminum cover off the TCP and take a thin small 3/4" square (my guess) piece of foam rubber maybe 1/4 to 1/2" thick and put over the area on top of the TCP then replace the aluminum cover and tighten the screws as tight as you can without stripping them. This was supposed to put some pressure on the weak connection which was what the person said was causing the problem in the first place. He also commented that the TCP was very fragile and could not be repaired by regular means so be carefull.

On the other parts, if you are talking about the two black bodied parts sort of in the middle of the board those are transistors it looks like and they are only supposed to have two legs soldered along with the large joint on the top. If you want to test them take your Digital Multi Meter on the Ohms setting and check the following: Orient the long solder joint to the top and the lower left leg is the Gate the right leg is the Source and the Top area is the Drain. Using your DMM probes check between S-G, S-D and G-D and record all of your reading for both transistors. Someone better than I should be able to interpret your reading as to whether these are good or bad transistors. Try to google the part numbers to find a Data Sheet on them so you can check on spare parts and have info at hand.

[rigeback]

Re: HannStar Monitor

Here is a pic of the bottom side of the power board and one can see that
Q104 and Q105 are modified parts without the middle leg not being soldered, problem will be understand what replacement is required!
The current parts are numbered with 9977GH 50542

[rigeback]

Re: HannStar Monitor

Yep you're right it seems someone has been here before, I too wondered why the CCFL connections were not the same, however on the back there is other component replacement that are soldered in an odd way, will put some pictures on shortly.
As for the carrier tape N-5 it seems okay, N-7 is the line that has a slight problem durring start up, I would be interested in hearing what you read about the tape carrier though.
Thanks