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Equipment Repairs => CRT TV forum => Topic started by: dboy23 on February 06, 2008,10:59:46

Title: Need help Sharp 21V-K200S wont turn on
Post by: dboy23 on February 06, 2008,10:59:46

Hello TV experts,
My TV wont turn on (stby only). When I turned ON the main power botton, the led is on red (standby) and when I turned ON the power on the remote, the led is green for a few seconds only and then it goes back to standby (led red). I need to turned off and on the main power button before I can change the led to green (but for a few seconds only). I checked the board, I found out that the vertical IC have cold solder, I resoldered it and still the prob occurs. Pls help what other parts/components to check. Thanks in advance!
Note: when the led is on green (few seconds only), no picture on the screen and sound.
Anyone have diagram with this model? Thanks!

Title: Re: Need help Sharp 21V-K200S wont turn on
Post by: P.R.Gore on February 13, 2008,09:00:33

Such model is not known to me. If you mention chassis no. perhaps I can help you. Green light indicates EHT generates but some kind of protection acts & set goes into stand by. If possible check SCL, SDA bus. Chassis no. is generally written near FBT. If you can not find chassis no. mention the IC’s used in it!   ::)

Title: Re: Need help Sharp 21V-K200S wont turn on
Post by: dboy23 on February 13, 2008,20:17:34

ok thanks for replying!
I will look at chassis no.  later after my work.
The IC used in power supply is TEA2261.

Title: Re: Need help Sharp 21V-K200S wont turn on
Post by: dboy23 on February 14, 2008,11:12:29

during standby, there's a humming sound on the transformer.

Here are the numbers I saw on the pcb. I am not sure which one is the chassis no.:

21V-K200S
08080297
PCB name --> DUNTK9428WE
QPWBF9428PEN3

Title: Re: Need help Sharp 21V-K200S wont turn on
Post by: nhoy_mags on February 22, 2008,10:12:36

check the hot output...it may shorted

Title: Re: Need help Sharp 21V-K200S wont turn on
Post by: dboy23 on February 29, 2008,04:45:51

I already have TV diagram (pls see attachments, power supply only). And I found out that R511 (1.5 ohms near FBT to 24V Vcc of Vertical IC) was open. After replacing this resistor, then turning on the TV, this resistor burned. I tried to remove the vertical IC and replace again the R511 resistor and check the 24V Vcc line of this IC and I measure around 30V instead of 24V (note: CRT is detached to the board when measuring). Anyone could explain why I measure 30V instead of 24V when vertical IC was removed?  Does vertical IC influenced the FBT input? And also 185V (YBN1) is only 100V.  Pls advise.

Note: 115V and 12VA on the 1st page are already ok. IC751 input and output are also ok.

Title: Re: Need help Sharp 21V-K200S wont turn on
Post by: nhoy_mags on February 29, 2008,21:13:30

hi,replace the vertical IC..this IC is shorted.reason  why the resistor keeps blowing.don't woryy the 30 volts,its normal since there is no load(vertical ic).

Title: Re: Need help Sharp 21V-K200S wont turn on
Post by: dboy23 on February 29, 2008,22:17:58

Thanks nhoy_mags!
I will buy and replace this vertical IC.
Do you have an idea about the 100V instead of 185V on YBN1?

Title: Re: Need help Sharp 21V-K200S wont turn on
Post by: nhoy_mags on March 03, 2008,18:58:33

check feedback IC(SE115 or 120).or check any capacitor rated .47uf.around the regulator IC.

Title: Re: Need help Sharp 21V-K200S wont turn on
Post by: dboy23 on March 06, 2008,22:45:57

after replacing the vertical IC and R511, the TV is now OK.
YBN1 voltage is now 185V when the board is connected to the CRT (if not connected, it is still 100V).

Thanks to nhoy_mags and to this site!

Title: Re: Need help Sharp 21V-K200S wont turn on
Post by: nhoy_mags on March 08, 2008,00:12:35

it's my pleasure to help and to be helped.hehe..
btw, where you from sir dboy23?

Title: Re: Need help Sharp 21V-K200S wont turn on
Post by: dboy23 on March 08, 2008,01:10:41

I'm from Manila :)

Title: Re: Need help Sharp 21V-K200S wont turn on
Post by: nhoy_mags on March 08, 2008,01:41:45

haha.ako sa laguna.add mo ko sa ym..nhoy_mags@yahoo.com

Title: Re: Need help Sharp 21V-K200S wont turn on
Post by: dboy23 on March 28, 2008,11:32:17

Hello again,
I noticed that the picture is slightly stretch.  The bottom part of the picture is missing (1/4 inch).  How can I adjust the picture? There is no vertical adjustment.  What is the possible problem?
Pls advise.
Thanks in advance!