IBM L170 17" monitor "2 second on then black"

[jetadm123]

Re: IBM L170 17" monitor "2 second on then black"

According to the BIT3105 spec sheet, the minumum voltage for pin 15 and 18 is 4V. You have over 8V and with the jumper in place, the ccfl's should be fully lit.

Hold on a sec. Reviewing your inverter transformer secondary readings, post # 28, you have 1043 versus 1111. This seems way out of sync and could be the source of your problem. They should be within approx. 3% of each other.

[ilikesteel]

Re: IBM L170 17" monitor "2 second on then black"

budm-adm123,

I'll check later this evening for the backlight and screen light after dark.

123adm, you think one of the transformers may be bad by the resistance readings?

I'll have to find out about checking the lamps.

thanks again....

[jetadm123]

Re: IBM L170 17" monitor "2 second on then black"

Since they're identical model transformers, you would expect the secondary resistance readings to be very close to each other. On this forum, the generally accepted tolerance between the two should be no more than 3%. Resistance readings are not the most accurate way to test a transformer, but at least provide some insight.

Without the jumper, when the monitor goes through it's cycling, did you notice if all 4 of the ccfl's light up?

[ilikesteel]

Re: IBM L170 17" monitor "2 second on then black"

adm123-budm,

I'll try tonight without the jumper and look for the 4 ccfl's to light or flash. a stand alone ccfl checker would be nice. just plucc the ccfl in and see if it lights.

will report back.

[ilikesteel]

Re: IBM L170 17" monitor "2 second on then black"

was able to some checking in a dark area of my basement. this is what I found.

JUMPER IN:
power connected to monitor, interface connected, pc power is off.

every 4-5 seconds screen backlight comes completely on, back lighting the whole screen and flashes. no logo appears.

JUMPER REMOVED:

power connected to monitor, interface connected, pc power off.

IBM LOGO appears when the screen flashes. green led on, 1 second later screen flashes logo. led goes off, screen goes blank, 8-9 seconds later, led goes green, LOGO flashes on screen, led goes off. this is a repeating cycle.


Now I turn the PC on:

same symptoms as above.

Then I checked the voltages as this was going on.

power to monitor, interface connected, pc is off, jumper still removed.
The 13V leg measured 16.29V when the green led was on and the screen flashed. it dropped to 11.60 when the led went off. again, these measurements repeated for the cycling of the led and the logo flashing on and off.

the 5V leg measured 5.14 when led was green and screen flash, then dropped down to .7V when screen was blank and led off.

any thing make sense? I'm willing to do more testing and isolation.

thanks a bunch.... frank

[budm]

Re: IBM L170 17" monitor "2 second on then black"

So if jumper in place, then when you turn on the PC and monitor you should see logo.
"power connected to monitor, interface connected, pc power is off.no logo appears"
The reason you do not see logo because when the PC in not on, there will be no signal to turn on the T-CON board. But regardless, with the jumper in place we are forcing the inverter to on no matter if you have the signal from PC or not, the backligts should stay on the minute you apply the power to the monitor without hitting the power switch. You do need to use test lamp at this point, otherwise we cannot be 1005 sure that your lamps are good or not.

[ilikesteel]

Re: IBM L170 17" monitor "2 second on then black"

budm,

trying to understand how the lamps and inverter work. with the jumper in you said the inverters should have lit the lamps instantly. the power supply also has the inverter built into it.

if one lamp is defective, will that keep the other three from lighting up?

can I disconnect all 4 lamps, then try them indiviually on the inverter? will a good lamp light by it's self with the inverter if the voltage is correct?

can I check for ac high voltage using the meter and where are the outputs to the lamps coming from?

thanks for the help...... not sure about this one ....

[budm]

Re: IBM L170 17" monitor "2 second on then black"

When the PWM IC detects fault such as over current, or lamp dose not fire up and stay on after 3 seconds, then its output drive to the Gate of the MOSFET will be shutdown and stays in shutdown, it will be reset when the power is removed, then it will try again. The sensing circuits looks at all the lamps, so one bad one will shutdown the whole circuits.
You can hook up one lamp at a time to see if each one will flash on for a second, but the problem is that if it has loose wire at the end of the lamp, the voltage can jump over the connection and will cause the lamp will fire up for seconds also. That test wil only tell you if you have completely dead lamp but not loose wires.
You cannot use your meter on the output because the out put can be as high as 2000V during fire up sequence,m then it will drop down to about 800~1000V range, your meter input circuits will be destroyed.

Bad lamp assemblies:
http://s807.photobucket.com/albums/y...klight%20lamp/

[ilikesteel]

Re: IBM L170 17" monitor "2 second on then black"

budm,

if I put the jumper back in place, and try each lamp by itself, would that prove anything? I don't have a lamp tester on hand but may want to get one or build one.

can one lamp be used and have the inverter work properly? If one inverter is working properly will it light a good lamp.

since there are only two transformers, does each transformer supply voltage to two lamps?

thanks again ....

[budm]

Re: IBM L170 17" monitor "2 second on then black"

You have four lamps, one per connector (4 connectors total). If you only have one lamp hookup, the lamp will flash on and then the Inverter circuits will go into shutdown as explained in post68.
Yes, each transformer will drive two lamps.

[ilikesteel]

Re: IBM L170 17" monitor "2 second on then black"

budm,

ok, looks like I need to get at least one lamp for testing.

if I use a spare lamp and eliminate one lamp at a time, would that be suffiecient to eliminate or condemn that one lamp is bad?

if the other three light up with the spare, then a bad lamp.

if spare lamp doens't show a bad lamp and symptoms remain the same, can I assume the ps/inverter board is bad?

thanks again... frank

[selldoor]

Re: IBM L170 17" monitor "2 second on then black"

budm,

ok, looks like I need to get at least one lamp for testing.

if I use a spare lamp and eliminate one lamp at a time, would that be suffiecient to eliminate or condemn that one lamp is bad?

if the other three light up with the spare, then a bad lamp.

if spare lamp doens't show a bad lamp and symptoms remain the same, can I assume the ps/inverter board is bad?

thanks again... frank

That would be ok unless you have 2 or more bad lamps. If the wires to the lamps are long enough try swapping them over to see if it makes any difference.

You could do the lamp tests as in here
https://www.badcaps.net/forum/showthread.php?t=10419 see post19

[budm]

Re: IBM L170 17" monitor "2 second on then black"

"if the other three light up with the spare, then a bad lamp." That is correct.
"if spare lamp doens't show a bad lamp and symptoms remain the same, can I assume the ps/inverter board is bad?" That is correct.

The bad part about using just one lamp for testing is that you may have more than one bad lamp.

[ilikesteel]

Re: IBM L170 17" monitor "2 second on then black"

budm,

ok, thanks. I''ll start looking for some lamps.

frank

[Rtech]

Re: IBM L170 17" monitor "2 second on then black"

The 'test' ones dont have to be 17",.....15" would do and possibly 19" as well dependant on the Inverter.

[ilikesteel]

Re: IBM L170 17" monitor "2 second on then black"

Rtech,

ok Rtech, I'll keep that in mind. again thanks to EVERYONE for all the input and advice. you guys are incredible.

frank

[budm]

Re: IBM L170 17" monitor "2 second on then black"

ilikesteel, thank you for finding this inverter.

[killian6pk]

Re: IBM L170 17" monitor "2 second on then black"

ilikesteel, thank you for finding this inverter.

Bud check this one out.

http://www.ebay.com/itm/220807798195...84.m1423.l2649

Of course I think you have made your own, haven't you?

[budm]

Re: IBM L170 17" monitor "2 second on then black"

Thanks, yes I saw that one, ilikesteel sent me the link also, but the one for $9 that will drive 4 lamps is ar real good deal for DIY repair.
Yes, I made my one using old guts from broken monitor.

[ilikesteel]

Re: IBM L170 17" monitor "2 second on then black -UPDATE"

hello again. for budm and all the guys who previously replied with suggestions to my problem with this monitor.

I ordered a stand alone 4 lamp inverter board and a 12V tiny power supply board. I had the ac to dc 12V wall wart for power. when I plugged all four lamps into the inverter board and switched the power on, the whole screen lit up with equal brightness all accross the screen.

So I'll assume the lamps are good, correct?

so I tried testing the monitor again. reconnected the lamps, added power to the monitor and turned it on. I still only see the flashing IMB logo with the THINKVISON under the logo. can see the lamps flash on then off.

so then I connected the monitor to a pc, cabled the interface to the pc and powered on the pc. I only receive the flashing IBM logo and THINKVISION. Shouldn't I see the boot process, like starting windows, and finally my desktop.

I don't get anything you would normally see upon booting, just the flashing IBM logo. It appears the monitor and PC do not see each other. could it be the interface board and not the power supply board. perhaps it's not generatiing the signal to the power supply that it's really there.


What's next?????? Again, thanks for all the help. the inverter board took awhile to get here from China!

frnak