electronics, repairs, service manuals and datasheets discussion community for the repairs professionals and technicians
FAQSearchMembersGroupsRegisterProfilePM'sLogin/Out
LCD (CCFL) Inverter Repair

 
Post new topic   Reply to topic    Electronic equipment repair and service manual search discussion Forum Index -> Computer and office equipment repairs
View previous topic :: View next topic  
Author Message
devil_evoxxx
Guest





PostPosted: Sat Sep 05, 2009 8:56 am    Post subject: LCD (CCFL) Inverter Repair Reply with quote

Hi All,

I'm trying to repair a CCFL Inverter of a FlyBook PC with no success. Can someone have a schematic or some tips to troubleshoot this?

The Controller Chip is a Monolithic Power Systems - MP1010BEF.


Thanks

David
Back to top
vtech



Joined: 08 May 2006
Posts: 1264
Location: USA

PostPosted: Sat Sep 05, 2009 11:13 pm    Post subject: Reply with quote

Doubt if you could find the specific schematic for the flybook. The alternative would be to look at the data for the controller IC from the manufacturer MPS to get a general schematic of the device's application and start checking for the basics.
Back to top
View user's profile Send private message
devil_evoxxx
Guest





PostPosted: Sun Sep 06, 2009 9:45 am    Post subject: Reply with quote

Thanks for the reply vtech.

I've already downloaded datasheet of MP1010BEF from the IC manufacter site.

I have tested with scope the signal coming from Notebook and all it's ok. After, i try to look the signal on pin 10 (one of the output connected to the primary coil of the transformer) but there are only 0.65v DC, no waveform. If i disconnect the trasnformer from the pcb i can see a small square wave of 1.25Vpp.

Any Idea?

Whath should i see on the two pin of the primary coil? A signal like a PWM?


Thanks

David
Back to top
vtech



Joined: 08 May 2006
Posts: 1264
Location: USA

PostPosted: Sun Sep 06, 2009 4:56 pm    Post subject: Reply with quote

Can't tell what is suppose to look like but you need to be able to see some sort of a pulse. Remember, in general for a transformer to operate, you'd need to have as close to a sine wave as possible. In this case, either side of the primary is above the main ground by means of the bleeder resistor and although you should be able to see either half from ground, if you want to scope the full output, you should be looking across the input coil without having to disconnect the txformer. If you can not see a pulse, you need to investigate further as the IC may be in shut down mode? In looking at the schematic, there are many possibilities that could shut down the IC. Pins 2.3.5.16.17.18.19 all of which are designed for some means of control. Re-read the data sheet and monitor each pin. Also any thing from an open lamp or shorted SMD cap along the way can trigger the shut down.
Back to top
View user's profile Send private message
SZASZ



Joined: 27 Apr 2007
Posts: 69
Location: TIMISOARA

PostPosted: Wed Sep 30, 2009 6:46 am    Post subject: Reply with quote

Are you shure thet the transformer is ok.
I have the same case replace the transformer and it's ok.
The transformer has two coils one is about 2-3 Ohms, and the second has about 700Ohms, that in my case is faulty.

The transformer has just one pin conected on the side of ccfl lamp connector.
Back to top
View user's profile Send private message
devil_evoxxx
Guest





PostPosted: Mon Oct 05, 2009 8:56 pm    Post subject: Reply with quote

No, the transformer is not ok, but i can't find any reseller for the transformer. Where you buy your transformer?

By

David
Back to top
Display posts from previous:   
Post new topic   Reply to topic    Electronic equipment repair and service manual search discussion Forum Index -> Computer and office equipment repairs All times are GMT
Page 1 of 1

 
Jump to:  
You can post new topics in this forum
You can reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Електроника София - Service Manuals Free Download - Prikachi - Service Diagrams

Free TV Schematics Download - HARDW.net - Pinout Master - Jabse Search - Jabse.InK  - Pulsator

Connector Pinout Forum - Новини - SnimkiOt.com - безплатен DNS - Whois разузнаване - Poblizo.com : пътешествия