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Equipment Repairs => LCD TV forum => Topic started by: Turnip on September 10, 2015,10:02:41

Title: Hitachi 42HXT12U - Vestel 17IPS20
Post by: Turnip on September 10, 2015,10:02:41

Hi folks,

Have one in where cust suspected lightning strike, but sort'a doubt it. Checked primary side of PS and all seems well, normal'ish voltages on all FETs - Secondary sides - Nothing at all, anywhere. Thought usual diodes S/C but no problem there.

Was looking about for a S/by PS but couldn't find one - Wonder where s/by supply comes from ?

Have shematic from Elektrotanya for 17IPS20-5p which looks a little different as don't seem to have a relay on my board.

Note 'Ohms' do a repair kit, but suspect it's a for primary pop, which I don't have this time.

Any thoughts ? - Thanks - Chris.

Title: Re: Hitachi 42HXT12U - Vestel 17IPS20
Post by: Keith on September 10, 2015,10:09:38

Hi Chris,

If it has 17MB9x main board 99% of the time the firmware is corrupt, replacement main board is the usual way.
 
Will check my notes
Keith

Title: Re: Hitachi 42HXT12U - Vestel 17IPS20
Post by: Turnip on September 10, 2015,10:40:49

Thanks Keith,

Those Vestel Main boards keep us solvent, if can find the right one on the Flea, with all screen maker and size variations.

Wonder if there's a check list anywhere, as have found that some with slightly different code numbers, work in a particular set.

Some folks like 'Emos' give suggestions if they know them, other folks just remove from smashed screen sets without noting screen size of maker.

Still wonder where the S/by supply comes from - Thanks - Chris.

Title: Re: Hitachi 42HXT12U - Vestel 17IPS20
Post by: michael first on September 10, 2015,18:38:53

hi,I have exactly the same problem with a 17IPS20(mounted on a 50inch Toshiba);no way to find the right

schematic as U202 is different from the one on the available schematics;anyway,it's U202 to drive the stage that

delivers the +12V from which the +5V stby voltage is derived;I don't know yet why it stands still!as

Bruce writes,I keep trying.

Title: Re: Hitachi 42HXT12U - Vestel 17IPS20
Post by: Keith on September 11, 2015,03:21:08

Vestel circuit diagrams are not easy to read. They seem to use one diagram for multiple versions, the diagram will show links and components which may or may not be present, making the circuit flow difficult to follow.

+5V stby is from Q212 via +12VCC_S. pin 3 of CN4 is power on

Title: Re: Hitachi 42HXT12U - Vestel 17IPS20
Post by: Turnip on September 11, 2015,12:39:19

Thanks Mike and Keith,

Was expecting the usual S/by supply with a small chip and trannie. Had a good look at the diagram and note  S/by supply derived from 12vcc, but of course I have no 12vcc for some reason.

Thought easiest option might be both Power and Main from the Flea - Hitachi 42HXT12U though gather this model has both Vestel and LG screens - Mine is Vestel without the T-con panel - Chris.

Later - Power board did the job, main board OK this time.

Title: Re: Hitachi 42HXT12U - Vestel 17IPS20
Post by: michael first on June 03, 2019,05:55:05

Hi Keith,the Vestel schematics are not only difficult to read but straightforward incorrect and approximate in some cases.well

we have to deal with no matter how frustrating it is.