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

[budm]

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

Are you using the new lamp driver board to drive the lamps and running it off the external supply and have every thing else hooked up?

[ilikesteel]

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

budm,

I only hooked up the inverter and power supply to the LAMPS only, the rest of the monitor was not connected and powered on. I thought about doing that but wasn't sure if the monitor power supply would prevent the monitor signal from being sent.

you want me to hook up the monitor to the pc fully connected, but using the new inverter board and 12V power supply to supply the voltage for the lamps?

thanks....frank

[budm]

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

Yes, we want to drive the lamps with your new lamp driver, and the existing power supply will still be connected to the main board as before without having the lamp driven by your old board, then apply the video signal from PC to drive the main board. All we are doing is using your new board to drive the lamp so the screen will have the light source for you to see the screen.In other word, you are replacing the bad inverter circuit with your new inverter board to test the main board function.

[ilikesteel]

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

Budm,

SUCCESS. Yes, the monitor worked properly with me powering the lamps with the new inverter board. so now what, got to be the inverter section of the power supply, right?

what is the next logical step to isolate the bad area? there may be available a used power supply on ebay. is it worth troubleshooting the bad supply?

Thanks budm and everyone who has contributed toward resolving this problem. the 4 lamp inverter board went a long way to help isolate the problem.

frank

[budm]

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

Yes, the inverter section is bad that we will need to look further to find out which component is bad.
So one option is to go back and troubleshoot the inverter circuits down to component level.
Second option is to use this new inverter board inside the unit, you can disconnect the power to the old inverter section and use that B+ to feed your inverter board. We can also trace out the on/off control pin of the old board and use that signal to turn the new inverter board on/offf, second signal will be the dimming signal so you can dim the new board.

[ilikesteel]

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

Budm,

Ok, which troubleshooting method would you suggest I try? I' game for any one of them. how would I install new inverter board with the old PS?

How can we isolate bad components on the inverter side of the PS?

frank

[budm]

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

I rather go with using your new board, it is the cheapest way. First, do think you have room for this board to sit inside the monitor?

[ilikesteel]

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

budm,

I tried to fit the new inverter inside the monitor. just can't make it fit properly. the best area I found was on top of the original power supply on the side where the two transformers are. it fits tightly when the outer metal assembly is attached. it does have plastic all around the inverter. I'm afraid that if it's pushed down against the transformers under the metal assembly on the original power supply it could cause a problem. what do you think? what would be the next course of action?

Thanks.... frank

[ilikesteel]

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

Budm & company,

Since I know the inverter part of the PS board is bad, I found a replacement on eaby from china. It's a new board for 16.00 including shipping. it will take a few weeks to get here, but that's ok. thanks for all who made suggestions to repair this monitor.

The new 4 lamp inverter board I bought proved the lamps were ok.

using the new inverter board and the monitor connected to a pc, the monitor worked. I now know the logic board in the monitor is also working, leaving just the inverter part of the PS as the problem.

Thanks again to everyone who contributed especially to Budm for his hand holding me along the way.

frank

[Lumberjack777]

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

I believe those two pins are fed off the 13V rail and now we need to find out why the 13V is not reaching the inverter section. The power supply is made by Samsung and used in several models. Some versions of this power supply did use a fuse between the 13V output and the inverter section. And in most cases they hid the fuse using white silicon adhesive. In your second photo, lower right side, above the wiring harness with the blue wire, there are two caps and a inductor with white adhesive between them. Carefully, remove some of that adhesive to see if there's a fuse there. It should be green in color.

I had replaced the caps in this model and tested just about every component I could see. I had to put this one aside for awhile and came back to give it another try. I saw what jetadm123 had posted and decided to go back and take a 2nd look. I normally just trim the adhesive away from the capacitors and replace them. I started to trim away the adhesive. And sure enough, there is was! That little green hidden picofuse! And sure enough the fuse tested open. I replaced the fuse and the monitor fired right up. Thanks jetadmin123!

[retiredcaps]

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

That little green hidden picofuse! And sure enough the fuse tested open.

There is where silkscreening both sides of the board would help. You would have found the fuse from the pcb designation on the backside.