# Solved: Philips TV 21 PT5437- DEAD- not turn on, please help me!



## zeetbear (Feb 21, 2012)

Philips TV 21 PT5437- DEAD- not turn on, please help me!

Hi to all, my tv doesnot turn on, do nothing dead, i have good analog meter & i can sold any ic or transistor but i am unsure which part is broken or faulty, any expert here to help me, i am very sad because it doesnot turn on :-( tell me how to check & which component can be faulty,,, thanks

*i have written ic numbers or transistor numbers present on the circuit board--> *

1) STRW6554A ic601

2) TDA4864AJ VF36YOB

3) D5023 707C II

4) L 7808 CV GKOVB VB

5) TFA9842AJ N7K2F616

6) TDA9370PS/N3/A CH7296 70701600

*
ORIGINAL PICTURES OF MY TV BOARD here--> please visit link 
*
http://tinypic.com/useralbum.php?ua=QzsZVILTtvoSd%2FtMVqz49w%3D%3D&type=images


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## ARTETUREN (Dec 2, 2007)

Do you have schematic diagram?

*First rule!*

Looking carefully at first. /several times/ without power!!!!!!!!!!

*All measurments without power, just instrument!!!!!!!!*

The main

Primary circle!

check

Input switch power supply!

main switch, fuse, resistor (few Watts, few ohms), input diodes, safety resistor or change smps ic STRW6554A

Secondary circle!

High voltage circuit (horizontal deflection)

transistor/fet, high voltage transformator /very often/, diodes around.

IC-s very rarely goes to the Manitou 
Do you hear any sound after turn on the Tv set, or smell?


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## zeetbear (Feb 21, 2012)

Thanks 4 your help,

My Tv real model number is--> Philips TV 21PT5437/94 SK4.0A CA

i have already replaced IC STRW6554A & i dont have schematic service manual of my tv board,

i heard nothing when i press powerbutton, tried several times..

yeah your are right--> i am going to change Hot transistor D5023 attached with heatsink

tell me how to check high voltage transformer? i dont know where it is, you can check images of my board

My Tv board high resolution pictures of circuit print side for closer look---> 

https://rapidshare.com/files/3612750504/Philips_21_PT5437-94.rar


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## ARTETUREN (Dec 2, 2007)

If you don`t hear anysound in the moment when push on the button it means no charge C609 100µF/400V or any impuls over input transformer (electronics break in the STR6554). In some case this capacitor can be weak.

http://www.eserviceinfo.com/download.php?fileid=50328
please download it. - four part just 5 MB

This is a link for manual and schematics diagram for Philips TV 21PT5437/94 SK4.0A CA. But I saw on other forum that you had said no relay. (page 13, 7. cicuit and pwb layout). 
It`s not important because i am supousing that optocoupler IC 602 makes stand by.

*ALL WITHOUT POWER!!!!!!!!!!*

At first check with ohmmeter main power switch sw 601. (Must be zero ohms when push on the button)

fuse F601 - at your picture looks good but check

D605-608 (? do you know about semicoductors - it dependes about polarity check)

R 603 - few ohms (5Ω ) - If is fuse ok this is the first one on the list.

R 607 - 22 ohms
D 603 - dioda 
change capacitor C610 - 10µF/ 50V (or any voltage over)

This is for begining.

The problem can be on the secondary circle of the power supply R616-620 (must be short connect) or diodes D610-614.

I`ll download your rar 145 MB .

For high voltage transformator you have static and dynamic probe. But quick way - if the Q303 - (fet) is a live hvt is ok.

How your tv stop the work?


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## zeetbear (Feb 21, 2012)

Thanks alot ARTETUREN,

Your knowledge is great, i hope you can understand my problem,

i have checked the voltages around my C609 it gives me reading 290 Volts DC, & 680 Volts AC, in my country voltage standard is 220/230 Volts,

Do you think optocoupler IC 602 can be faulty here, because of that tv is dead?

How can i check it?

I checked with ohmmeter main power switch sw 601 working good,

fuse F601 is fine,

D605-608 (show reading only in one direction that means its not shorted)

other components i will check them, as your said, 

Do you think HOT Q302 D5023 can be faulty? i am buying new D5023 very soon, 

I am very thankful to you


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## ARTETUREN (Dec 2, 2007)

Very good for trying. 
I forgot something *cold soldered joint *- in the most cases this is a reason of malfunction.
Yellow area - you can see some of them. 
Use solder.










You are from Nederland, I presume.
Yes .. around 300 V dc is correct on the C610. It`s peak value of sinusoidal (effective) voltage 230 V. 
Multiply by √2 (square root of 2)
AC value isn`t correct if you measure on this way. There is no alternating current(voltage) .. only ripple (few %) 
You have old analog instrument and it was calibrated for show that value but it is not true.

For diode yeaa ... one way - infinite, other way about 130 to 700 mV or ohms (on analog instrument) In your case around 550.

In the next post i will show you several solutions and explanations for check parts
For the D5032, similar like a diode /reason integrated diode in it/, one way very big. other polarity small. (direct check on the board ) Hold wires of instruments few seconds on the joint colector and emiter.

Be careful with voltage on C610. Several minutes after you turn off will be high voltage on him.


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## zeetbear (Feb 21, 2012)

thanks,

i will resoldered those *cold soldered joints* you mention in the picture,

in last reply i said i have checked *C609(450 VOLTS 220 UF) *
not C610--> you said replaced C610, tell me how to check C610?

one thing i want to mention here that when i select RX1, my MULTIMETER was not touch zero ohms when i touch negative & positive leads together, inspite of adjust knob adjusting still shows 3 ohms not zero, may be due to weak battery, is it a problem in my previous test readings? should i replaced battery of my multimeter?

i have checked Q302 Hot D5023 attached with heatsink-->

Multimeter with selector set to X1 150mA,
*perform following tests: *

1) touch RED PIN to 1st Pin(base) & BLACK to middle(collector) gets Infinite(no reading)

2) touch RED PIN to 1stPin(base) & BLACK to 3rd right(emitter) gets 55 OHMS reading (meter not set to 0 ohms)

3) touch RED PIN to 2nd(collector) & BLACK to 3rd right(emitter) gets 7 OHMS reading (meter not set to 0 ohms)

4) touch RED PIN to 2nd(collector) & BLACK to 1st(base) gets 7 OHMS again reading (meter not set to 0 ohms)

5) touch BLACK PIN to 2nd(collector) & RED to 3rd(emitter) gets infinite(NO READING)

on the other forum there is a guy MEL, he help me alot, he said your Q302 (D5023) is faulty, You should replace it with new one, i am looking the original replacement, will arrive in 2 days,

IF YOU WANT TO SEE MORE CLOSER CAMERA PICTURES OF MY TV BOARD FROM UPSIDE, i will upload them 4 better understanding,

or VIDEO OF TESTING ANY PART WITH MULTIMETER, i will upload on youtube,
tell me i will show them to you,
thanks again


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## ARTETUREN (Dec 2, 2007)

UUU my very long post eaten by a server ..

You have another cold joints!!

*all yellow area *

and check red area 
I `ll write again ..


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## ARTETUREN (Dec 2, 2007)

zeetbear said:


> thanks,
> 
> i will resoldered those *cold soldered joints* you mention in the picture,
> 
> ...


you welcome

C610 - 10 uF is supply for STR. You need osciloscope, or pull out then need capacitance meter. 
But price for brand new is few cents.
And yes little mistake by me, I meant on charged C 609 



zeetbear said:


> one thing i want to mention here that when i select RX1, my MULTIMETER was not touch zero ohms when i touch negative & positive leads together, inspite of adjust knob adjusting still shows 3 ohms not zero, may be due to weak battery, is it a problem in my previous test readings? should i replaced battery of my multimeter?


You need just relative position of pointer. Yes the reason is an old (weak) battery. Maximum current from instrument is at short leads (cords)



zeetbear said:


> i have checked Q302 Hot D5023 attached with heatsink-->
> 
> Multimeter with selector set to X1 150mA,
> *perform following tests: *
> ...


Yes, it is bad - this is 2SD 5032.

http://www.ic-on-line.cn/view_online.php?id=1486885&file=0244\3dd5032_5047576.pdf

You see this is transistor with integrated resistor 50 ohm between base and emiter ...
Rest of text will be soon ... 



zeetbear said:


> IF YOU WANT TO SEE MORE CLOSER CAMERA PICTURES OF MY TV BOARD FROM UPSIDE, i will upload them 4 better understanding,
> 
> or VIDEO OF TESTING ANY PART WITH MULTIMETER, i will upload on youtube,
> tell me i will show them to you,
> thanks again


No need for it, your writeing is enough :top:


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## ARTETUREN (Dec 2, 2007)

Check for Flyback = high voltage transformer

Just between pins 1, 2 & 10 short circuit. 
One cord on pin 1 (it doesn`t matter black or red), another around pin by pin of HVT.

*All without power!!!!!!!*

Check safety resistor (must be short circuit) R314. 

Also check 
R 616 617, 618, 620 (must be short circuit)
and D 611, 612, 613, 614 

btw if you need substitute for D5032 i can found it or you can made it very simply.

also you have two knobs on HVT, focus and screen, gently few angles left or right for better picture after all.


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## zeetbear (Feb 21, 2012)

thanks ARTETUREN,

i don't understand the meaning ---> (must be short circuit) ??? please clear what do you mean exactly, you mean that part is bad? or no show reading?

You said Q302 HOT Transistor is 2SD 5032,
but on transistor wrote D5023 707C II 

ok, i will check all parts as you said, & tell me what is the replacement of HOT TRANSISTOR D5023?

i am very thankful to you,


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## ARTETUREN (Dec 2, 2007)

zeetbear said:


> thanks ARTETUREN,
> 
> i don't understand the meaning ---> (must be short circuit) ??? please clear what do you mean exactly, you mean that part is bad? or no show reading?


Safety resistors have very low resistance, under one ohm. This is a practical short circuit by instrument. They are like a fuses.

But your transistor isn`t just bad, burnt is the better word.



zeetbear said:


> You said Q302 HOT Transistor is 2SD 5032,
> but on transistor wrote D5023 707C II












You make mistake this is definite 5032 not 5023!. Japanese mark like a prefiks is 2S (american 2N) 
It mean 2SD xxxx = D xxxx, or in some cases for specifics DD xxxx (integrated diode). 
2S "gone" with time from the elements. Electronics men knew that. 
Yes, you have just D5032 but the full name is above.

2SA - pnp high freq transistors
2SB - pnp low freq transistors
2SC - npn high freq transistors
2SD - npn low freq transistors

707C II is factory marks for temperatury range, purpos .. etc.



zeetbear said:


> ok, i will check all parts as you said, & tell me what is the replacement of HOT TRANSISTOR D5023?
> 
> i am very thankful to you,


http://www.datasheetcatalog.org/datasheet/philips/BU2508DF_2.pdf

*BU 2508 DF* - direct replacement. DF is important

Put some silicone warm paste between transistor case and heatsink.


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## zeetbear (Feb 21, 2012)

Hi ARTETUREN,

why you don't believe me its D5023 i can show you closer pictures of this, anyways,

unable to get this & BU 2508DF tried alot :-(

but i have got BU 2527 DX 

tell me this could be possible replacement for Q302 Hot transistor?

if yes i will try this, may be it can work in this circuit :-S

yeah i will put some thermal paste between transistor & heatsink, thanks


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## ARTETUREN (Dec 2, 2007)

zeetbear said:


> ..
> 
> but i have got BU 2527 DX
> 
> ...


Excellent choice. *Yes*, this is better part then you need. If all around are ok, *it must work*. 
Have a good time.


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## zeetbear (Feb 21, 2012)

Hi ARTETUREN,

How are you buddy! 

i have replaced BU 2527 DX, but nothing still dead :-(

very sad, because as you said that will work with this board but the others components are not good around it, how can i check other components that can be faulty?

may be my tv will fix someday, thanks 4 your help


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## ARTETUREN (Dec 2, 2007)

zeetbear said:


> Hi ARTETUREN,
> 
> How are you buddy!
> 
> ...


Don`t give up. Tv is a "mankind" product . How your tv stop working? Do you heard any sound when you turn on tv with new transistor? Check the new part .. It will gone just like that, in few miliseconds.

Step by step.

Do you downladed schematics? Do you recoknize parts?

check parts at your picture - P2230263, between transformator and capacitors (diodes and safety resistors with ohmmeter) as I wrote.

In the power supply around STR - check parts too.


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## zeetbear (Feb 21, 2012)

THANKS ALOT ARTETUREN, 

i am very happy my tv is now working perfectly, as you said earlier check the resistors between transformers & capacitors---> i changed them & now my tv is working great, 

You're a nice person & i am very thankful to you,

GOD BLESS YOU


i thing i want to know here, i have one faulty chinese generator 1KW, its engine has a problem, mechanical problem, can you tell me where i can get help for that generator i want to repair engine, parts replacement...


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## ARTETUREN (Dec 2, 2007)

Thank You too.

You`re doing good job.

Also I`m happy because you are good thinker and finder.

We can try with generator on the new thread.


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