2 Seconds to Black - Gateway LE1936

[budm]

Re: 2 Seconds to Black - Gateway LE1936

From post 16 on this thread:
https://www.badcaps.net/forum/showthread.php?t=7777
It does look like you do have bad transformer. But do the lamp test first.

[tpearsall]

Re: 2 Seconds to Black - Gateway LE1936

I'm sure budm will help you figure it out. If it turns out to be an inverter transformer, you are in luck. I believe that part number is SPW-068.
http://www.ebay.com/sch/i.html?_trks...at=0&_from=R40
Except for my caps from Digikey; it seems like 99% of the parts I get nowadays are from China or Hong Kong.
I'm sure budm will help you track down the problem before you need to buy anything. Good luck. ~L-J-7~

That sure looks like it. Thanks!

[budm]

Re: 2 Seconds to Black - Gateway LE1936

You have to have all lamps connected, the circuit will shutdown if it does not detect the lamps or lamp is over loading the circuits.

[tpearsall]

Re: 2 Seconds to Black - Gateway LE1936

You have to have all lamps connected, the circuit will shutdown if it does not detect the lamps or lamp is over loading the circuits.

I had 3 CCFLs and the 1 test lamp connected. They all went on for 2 seconds then off. I didn't try the test lamp in place of each CCFL before I pulled the transformers which i think is what I was supposed to test.

Soldering the transformers back in to test all in 4 CCFLs spots.

Thanks!

[tpearsall]

Re: 2 Seconds to Black - Gateway LE1936

From post 16 on this thread:
https://www.badcaps.net/forum/showthread.php?t=7777
It does look like you do have bad transformer. But do the lamp test first.

I tested the CCFLs by plugging them into the inverter board one at a time. The CCFLs in T502 where bright. In T501, one did not light and other was dim. Next I plugged the "good" CCFLs from T502 into T501 they were dim/off and the CCFLs previously in T501 were bright in T502.

Is it save to assume CCFLs are probably good and T501 is bad and I should replace them both or is further testing needed?

T501
1 to 5: .5ohms
3 to 6: .5ohms
7 to 8: 679ohms
Rest were open

T502
1 to 5: .5ohms
3 to 6: .5ohms
7 to 8: 623ohms
Rest were open

Thanks.

[budm]

Re: 2 Seconds to Black - Gateway LE1936

On more test just to be sure so you do not have to order another part, we need to check the little blue ballast capacitors, all 4 of them, we will be looking for leakage resistance, no need to take them out, juts measure the resistance at the two legs.
It does look like T501 is bad.
So what did you use for the test lamp?

[tpearsall]

Re: 2 Seconds to Black - Gateway LE1936

On more test just to be sure so you do not have to order another part, we need to check the little blue ballast capacitors, all 4 of them, we will be looking for leakage resistance, no need to take them out, juts measure the resistance at the two legs.
It does look like T501 is bad.
So what did you use for the test lamp?

I bought a T5 4w but didn't use it. Before soldering/un-soldering all the connectors I did the "Alternatively, if you do not have a spare CCFL, then try this test." and tried each CCFL individually. When one did not light and one was dim on T501 I repeated the test putting those CCFLs on T502 and they where bright. In all cases they only light up for the 2 seconds. I didn't test with the test light, since everything out of T501 was bad.

To test the CCFLs for leakage resistance do I need to test at the legs or can I test from the connectors? I haven't opened it far enough to expose the CCFL posts. From the connectors they all read open.

Thanks!

[budm]

Re: 2 Seconds to Black - Gateway LE1936

Using one lamp at a time does work if the screen is not high contrast type, very hard to see unless you are in a dark room, that is why I like using test lamp. Poor connection at the lamp's end will still make the lamp light up for second also with normal brightness but will stop after warm up due to wire separation from the end of the lamp pin when everything expand when heat up.
So now you can order the two new transformers, just make sure to take the resistance reading to make sure they are OK.

[tpearsall]

Re: 2 Seconds to Black - Gateway LE1936

Using one lamp at a time does work if the screen is not high contrast type, very hard to see unless you are in a dark room, that is why I like using test lamp. Poor connection at the lamp's end will still make the lamp light up for second also with normal brightness but will stop after warm up due to wire separation from the end of the lamp pin when everything expand when heat up.
So now you can order the two new transformers, just make sure to take the resistance reading to make sure they are OK.

Makes sense. Thanks for your help, this has been a HUGE learning experience. I'll report back after the new transformers go in.

Thanks!

[tpearsall]

Re: 2 Seconds to Black - Gateway LE1936

New transformers came in and the monitor is back in business! (I have to admit I have 2 screws left over).

Thank you for all of your help and the education!

[budm]

Re: 2 Seconds to Black - Gateway LE1936

Thanks for the feedback on the repair.

[Lumberjack777]

Re: 2 Seconds to Black - Gateway LE1936

New transformers came in and the monitor is back in business! (I have to admit I have 2 screws left over).

Thank you for all of your help and the education!

We got really lucky those inverters tranformers were available. Thanks Budm for all your help out here.

So, you had 2 screws left over eh? Is that ALL?