Planar PE1700-BK monitor

[Tinbendr]

Rec'd three of these monitors. All have the same symptom. Flash of display, then black. Power LED is yellow all the time.

I only have a single power supply, but it appears to be working. Tested it with a small load (12v light bulbs) and voltage drop was 12.6 down to about 12.2v.

A word of warning. I an NOT a electronic technician. I am a aircraft mechanic by trade and can 'figure things out' when I set my mind to it. I know how to use a multimeter, but that's about it. While I understand most electronic concepts, I seem to struggle with how those concepts interact with one another.

I have been reading for a couple of days about bad caps. I have investigated the circuit boards, but have not been able to identify any suspect caps. I have searched the board for my model monitor, but have not seen boards like this one.

Are you up for a challenge?

David

[alexanna]

Re: Planar PE1700-BK monitor

What is the output rated amps on the power supply, and did your test lamp put a significant load on the power supply. An automotive 12v circuit tester/light may not.

[Tinbendr]

Re: Planar PE1700-BK monitor

What is the output rated amps on the power supply,

12 @ 3.33A

and did your test lamp put a significant load on the power supply. .

It was a towing trailer harness with bulb soldered in.

[PlainBill]

Re: Planar PE1700-BK monitor

If that's an 1157 type tail light, the total load is about 2.2 Amps if I recall correctly. I've got a similar jig and got burned when a power brick would supply enough current for the lamps, but would fail on the monitor. (Wasted a LOT of time with that one).

Check the voltage from one of the mounting screws to either end of F1 with everything hooked together.

PlainBill

[Tinbendr]

Re: Planar PE1700-BK monitor

If that's an 1157 type tail light,

Don't know. There's not a mark on it.

Check the voltage from one of the mounting screws to either end of F1 with everything hooked together.

12.6v

[alexanna]

Re: Planar PE1700-BK monitor

Don't know. There's not a mark on it.

12.6v

12 @ 3.33A

It was a towing trailer harness with bulb soldered in.

I have not been burned using Turn signal bulb YET. But knowing me it’s bound to happen.
I would think as long as you see above 12v under a load at the fuse when you try to turn the monitor on, you are OK.
I think it would be unusual for 3 monitors to have the same identical problem; really the only thing in common is the power supply.
However for right now try taking a load off the monitor, remove the flat cable from the logic board to the LCD panel. Is there any change in the behavior of the PLED or the backlights.
EDIT;I should add one thing I have very thick skin, and my feelings are not easily hurt.
So if anyone else has ideas goferit!

[Tinbendr]

Re: Planar PE1700-BK monitor

... for right now try taking a load off the monitor, remove the flat cable from the logic board to the LCD panel. Is there any change in the behavior of the PLED or the backlights.

With the ribbon cable disconnected, the screen flashes white, then off. The PLED did not change.

[alexanna]

Re: Planar PE1700-BK monitor

With the ribbon cable disconnected, the screen flashes white, then off. The PLED did not change.

You do have a signal with the VGA or DVI installed,correct?

[Tinbendr]

Re: Planar PE1700-BK monitor

You do have a signal with the VGA or DVI installed,correct?

Z-i-i-ing!! Did you hear that whiz over my head!!

Do you mean, "Do I have it connected to a VGA source?", then no, I do not.

[alexanna]

Re: Planar PE1700-BK monitor

Z-i-i-ing!! Did you hear that whiz over my head!!

Do you mean, "Do I have it connected to a VGA source?", then no, I do not.

Yes hook up a VGA source ,And describe what happens.
Have the ribbon installed to the pannel also.

[Tinbendr]

Re: Planar PE1700-BK monitor

Yes hook up a VGA source ,And describe what happens.
Have the ribbon installed to the panel also.

Ok. Connected the ribbon back to the monitor. Connected it to a laptop and I get the image of the laptop on the monitor for the same 1/2 second interval.

[alexanna]

Re: Planar PE1700-BK monitor

Well its what we call 2 seconds to black.
If you use the advanced search feature RetiredCaps has a very informative guide,I would suggest reading it particularly about CCFLs and substitution.
And after readsing you have questions pleas ask
Al.

[PlainBill]

Re: Planar PE1700-BK monitor

All of these tests are to be done with power off, and can be done without removing the components from the board.

On the inverter, check the resistance of F1 and F2. Also, on that connector pins 1 & 2 are power, pins 3&4 are Ground. What are the voltages on pins 5, 6, and 7? Try to get readings when the backlights are on, and when they are off.

And last (for now), if either F1 or F2 is open (more than 10 ohms), check the transistors Q8, Q9, Q15, and Q16 for shorts.

Yeah, our old friend the Royer oscillator.

Oh, and the pictures of the inverter are superb - I can even tell the transistors are Rohm 2SC4672.

PlainBill

[alexanna]

Re: Planar PE1700-BK monitor

On the inverter, check the resistance of F1 and F2.

PlainBill

Thank you

[Tinbendr]

Re: Planar PE1700-BK monitor

On the inverter, check the resistance of F1 and F2.

Both are about .6

Also, on that connector pins 1 & 2 are power, pins 3&4 are Ground. What are the voltages on pins 5, 6, and 7? Try to get readings when the backlights are on, and when they are off.

I do have 12v on 1 & 2.

5 is about .1 vbc anytime and 6, 7 don't read anything.

Oh, and the pictures of the inverter are superb - I can even tell the transistors are Rohm 2SC4672.l

I even went back to look for the transistors because it's easier.

If I need to check the Q's, you'll have to instruct me on that.

[alexanna]

Re: Planar PE1700-BK monitor

A reading of .6 of the fuses seems a little strange to me.
You say you see a flash of the back lamps, so at least one of the fuses has to be good.
You are also able to see an image on the screen for ½ of a second, so unless this particular monitor is doing something different that we usually see I would think we should see a backlight on signal and a dim signal for at least the ½ second that you can see an image, I would guess these voltages should be somewhere between 3 and 5 volts.
Would you recheck for these voltages? You will need to power off and on the monitor each time with the [front power switch], and the DMM probe attached to each pin.

[Tinbendr]

Re: Planar PE1700-BK monitor

A reading of .6 of the fuses seems a little strange to me.

It actually starts out about 1.0 then falls to .6 over about 5 secs.

and the DMM probe attached to each pin.

Between each pin and chassis ground, correct?

[PlainBill]

Re: Planar PE1700-BK monitor

It actually starts out about 1.0 then falls to .6 over about 5 secs.


Between each pin and chassis ground, correct?

OK, let's go back to the basics on this. Unplug power from the monitor. Set your DMM to the lowest resistance range, usually 200 ohms. Touch the probes together. What reading do you get? Now place 1 probe firmly on each end of F1. What reading do you get? Now place 1 probe firmly on each end of F2. What reading do you get?

The difference between the reading across each fuse and the reading with the probes touching is the actual resistance of the fuse, and should be less than 1 ohm for each fuse.

Now switch the DMM to the 20VDC range. Plug in the monitor and have it hooked to a computer displaying a desktop or something similar. Hold one probe on pins 3 or 4, and the other probe on pin 5. Press the power button several times at 3 to 5 second intervals. I would expect to see 0 volts when the power LED is off, and some voltage (typically 3-5 volts) when the power led is on. Move the probe from pin 5 to pin 6 and repeat. And again, to pin 7 and repeat. Also, do you get a flash of the display every time you push the power button and the power led comes on?

Very briefly, I suspect what you are seeing is 'Two Seconds to black'. With that problem the signal board is turning the inverter on, the inverter controller detects a fault condition, and turns the CCFLs off. The inverter receives two signals from the signal board - On/Off and Brightness. Each should have some voltage over 2 volts, and be stable while the power LED is on.

One more thing - what is the history of these monitors? Obviously we would be looking for different problems if they all failed at the same time as opposed to their being found in a firm's 'bad monitor closet'.

PlainBill

[Tinbendr]

Re: Planar PE1700-BK monitor

OK, let's go back to the basics on this. ...Now place 1 probe firmly on each end of F1...What reading do you get?

I'll check again when I get home.

Hold one probe on pins 3 or 4, and the other probe on pin 5.

OK, I was checking this wrong.

what is the history of these monitors?

Yep. a firm's leftovers. History unknown, but all three exhibit the same symptoms.

And I do realize that they all may suffer different problems, but let's just take one at a time for now.

[PlainBill]

Re: Planar PE1700-BK monitor

I'll check again when I get home.


OK, I was checking this wrong.


Yep. a firm's leftovers. History unknown, but all three exhibit the same symptoms.

And I do realize that they all may suffer different problems, but let's just take one at a time for now.

The operative word is 'may'. Certain brands have common failures. 'Mix and Match' until you get one working is a valid troubleshooting technique. Then you can say "I know the signal card, LCD panel, and power supply are good, so it must be the inverter".

PlainBill