Samsung CRT no power and ticking noise


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Samsung CRT no power and ticking noise

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imperatormk
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Nov 11, 2011, 7:20 PM

Post #1 of 110 (14753 views)
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Samsung CRT no power and ticking noise	Can't Post

Hello,

My Samsung CRT TV all of the sudden refuses to power up: it constantly makes ticking noise and the LED won`t power up. I`ve opened the TV and made some really basic measurements, but I have no idea where to search. Also the noise SEEMS to be coming from the SMPS transformer, but I might be wrong.

Any suggestions would be appreciated. :)

techchris
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Nov 11, 2011, 8:00 PM

Post #2 of 110 (14740 views)
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Re: [imperatormk] Samsung CRT no power and ticking noise [In reply to]	Can't Post

suggestion 1:

model number

jts1957
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Nov 11, 2011, 9:49 PM

Post #3 of 110 (14733 views)
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Re: [imperatormk] Samsung CRT no power and ticking noise [In reply to]	Can't Post

Check the Horizontal Output?
The Power Supply?
The Flux Capacitor?

-------------------------
Location: Far, Far Away

(This post was edited by jts1957 on Nov 11, 2011, 9:50 PM)

imperatormk
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Nov 12, 2011, 4:25 PM

Post #4 of 110 (14711 views)
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Re: [jts1957] Samsung CRT no power and ticking noise [In reply to]	Can't Post

I can`t seem to find the model number, but will search again later as the TV is not at my place. Until then - can you be a *little* more specific? I don`t know what the correct voltages & resistance should be, so I can`t find a problem. I`m suspecting at the chopper and flyback transformers. Do you have an idea how to test those parts? The chopper transformer has several pins that show low resistance, but it can be because of the low coil resistance, and not necessarily a problem. Can you give me some idea, because I am not too experienced in stuff like this, and yet I believe I can fix the set, with someones help :) 

(This post was edited by imperatormk on Nov 12, 2011, 4:29 PM)

techchris
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Nov 13, 2011, 11:59 AM

Post #5 of 110 (14695 views)
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Re: [imperatormk] Samsung CRT no power and ticking noise [In reply to]	Can't Post

unsolder the centre pin of the horizontal out transistor,then switch on and check for about 120volts on the board where the centre pin was connected to. if the voltage is ok then the power supply is probably ok and the fault lies in the flyback tx circuit most likely the transistor you unsoldered is short circuit .

imperatormk
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Nov 13, 2011, 12:33 PM

Post #6 of 110 (14694 views)
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Re: [techchris] Samsung CRT no power and ticking noise [In reply to]	Can't Post

So, I connect the red probe on the board where the centre pin was connected to, but what about the black probe? I guess on the 0V connection on the diode bridge? Sorry for my ignorance...

Ron.M
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Nov 13, 2011, 9:42 PM

Post #7 of 110 (14665 views)
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Re: [imperatormk] Samsung CRT no power and ticking noise [In reply to]	Can't Post

imperatormk;.....

Since techchris is a bit slow responding , I'll jump in & help out....

The "black" probe goes to chassis ground...
Usually the best place to get that is the tuner cover or the coax fitting on the tuner....
Be sure that the center pin is COMPLETELY separated from the board when you turn the TV on...

The 0V connection on the diode bridge may be at "HOT" ground potential & would give you an erroneous reading...

IF you get the 120 volts that techchris said , turn the TV off & unplug it...
Using a jumper , short the center pin connection ON the board to ground...
There will be a spark....
Then set your meter to ohms...
Set the range to Rx100....
Leave the "black" probe connected to chassis ground/tuner & connect the red probe to the center pin on the horizontal out transistor ...
You should get infinity for a reading...
That is to say your meter should not read anything...

The model number should be on a label on the back cover...
It may be needed later on.....

Good luck...

Later...Ron.M..... Cool

...
Veteran & Retired TV technician

(This post was edited by Ron.M on Nov 13, 2011, 9:54 PM)

imperatormk
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Nov 14, 2011, 3:55 PM

Post #8 of 110 (14646 views)
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Re: [Ron.M] Samsung CRT no power and ticking noise [In reply to]	Can't Post

OK, I made some measurements. The voltage between the points you mentioned turns out to be 100V when set on AC voltage. However, if the voltage is DC, I guess it would be ~50V because my multimeter multiplies the DC by 2 when set on AC. Should I be looking for AC or DC voltage? After you confirm that it`s DC, I`ll repeat the measurement and see if it`s really 50V (DC).

..and what should I do if that voltage is so low? Should I be looking for a short/open in the power (SMPS) section?

(This post was edited by imperatormk on Nov 14, 2011, 5:08 PM)

Ron.M
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Nov 14, 2011, 6:27 PM

Post #9 of 110 (14620 views)
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Re: [imperatormk] Samsung CRT no power and ticking noise [In reply to]	Can't Post

imperatormk;....

You should read about 120 volts DC ....
What kind of meter do you have that doubles "DC" when set on "AC" ????
Never heard of that before....

Quote

Should I be looking for a short/open in the power (SMPS) section?

NO , it's time to get the model/chassis number so I can try to get a manual...

Check that Horizontal output transistor for shorts just to be sure it's OK....

Later...Ron.M.... Cool

....
Veteran & Retired TV technician

imperatormk
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Nov 14, 2011, 6:39 PM

Post #10 of 110 (14618 views)
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Re: [Ron.M] Samsung CRT no power and ticking noise [In reply to]	Can't Post

Quote

What kind of meter do you have that doubles "DC" when set on "AC" ????
Never heard of that before....

I am not sure why does it happen, but never mind.

Quote

Check that Horizontal output transistor for shorts just to be sure it's OK....

There seems to be a short between C-E, but the transistor is OK when out of the circuit. I don`t think that this is normal, but I can`t seem to find the problem. That`s why I am here :)

Quote

NO , it's time to get the model/chassis number so I can try to get a manual...

So far, this is the best I could find (printed out on the CRT tube): A51 EER 131X78 and Telesan 21 STXB-2P That`s all I could find so far......

Ron.M
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Nov 14, 2011, 6:55 PM

Post #11 of 110 (14615 views)
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Re: [imperatormk] Samsung CRT no power and ticking noise [In reply to]	Can't Post

imperatormk;....

IF you are reading a "short" between C & E OUT of circuit , the transistor IS bad...Can NOT be OK !!!
I'm saying it's bad IF ALL pins are disconnected from the board & you take the reading...
Clarify please....

IF you are reading a "short" with C & E (Along with B) connected , then you have a short elsewhere...
"B" usually reads short to ground...
That is due to the horiz driver transformer being hooked up to "B"...

Look around the sidewalls inside the set & on the back cover for a white label with some other info on it ...
You might look on the chassis for some info...

Later..Ron.M.... Cool

....
Veteran & Retired TV technician

imperatormk
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Nov 14, 2011, 7:07 PM

Post #12 of 110 (14612 views)
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Re: [Ron.M] Samsung CRT no power and ticking noise [In reply to]	Can't Post

Well, there seems to be a misunderstanding. Actually, the transistor is OK (no short) when out of circuit, which means the short is on the board and not on the transistor itself, and that makes ALL output pins of the SMPS transformer to become shorted too.......

All the info I gave you are from the chassis along with the sticker on the CRT tube, but there might be written something else inside......

(This post was edited by imperatormk on Nov 14, 2011, 7:08 PM)

Ron.M
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Nov 14, 2011, 7:13 PM

Post #13 of 110 (14607 views)
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Re: [imperatormk] Samsung CRT no power and ticking noise [In reply to]	Can't Post

imperatormk;....

What about the voltage ???
Did you get 50 VDC or 120 VDC ???
FIRST read the ohms from the center pin of the Horiz out transistor ON the board to chassis ground , BEFORE you turn the set on & give me both readings...
Thanks.... Sly

...

Later...Ron.M..... Cool

....
Veteran & Retired TV technician

imperatormk
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Nov 14, 2011, 7:17 PM

Post #14 of 110 (14605 views)
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Re: [Ron.M] Samsung CRT no power and ticking noise [In reply to]	Can't Post

OK, I`ll give you the results ASAP!

imperatormk
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Nov 15, 2011, 4:29 PM

Post #15 of 110 (14586 views)
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Re: [imperatormk] Samsung CRT no power and ticking noise [In reply to]	Can't Post

So, I took the suggested measurements:

The voltage on the center pin ON the board turns out to be ~47VDC...

I kinda didn`t understand whether should I measure the resistance between the chassis and center pin ON the board or the disconnected center pin of the transistor BUT, I did the both, so use the one you actually need. Also, I got somewhat different readings when switching the probes:

Code

Black probe to chassis, red probe to center pin on the board: 47.5 KOhm  
  
Black probe to chassis, red probe to center pin of the transistor: INFINITY  
  
Red probe to chassis, black probe to center pin on the board: 47.5 KOhm  
  
Red probe to chassis, black probe to center pin of the transistor: 138KOhm when set on the 200K range, 968KOhm when set on the 2M range.

...and yes; I still can`t find the model number, it just seems not to be written anywhere on the chassis/inside...

What now??

(This post was edited by imperatormk on Nov 15, 2011, 6:28 PM)

Ron.M
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Nov 15, 2011, 8:28 PM

Post #16 of 110 (14516 views)
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Re: [imperatormk] Samsung CRT no power and ticking noise [In reply to]	Can't Post

imperatormk;.....

Two more questions;....
1)...What voltage are you getting at the center pin of the horiz output transistor connection ON the board with the TV OFF ????
2)...Does that voltage change when you turn the TV on , OR stay the same ????
(Meaning the 47 volts comes up..)

THANKS.... Smile

....

Later...Ron.M.... Cool

....
Veteran & Retired TV technician

imperatormk
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Nov 15, 2011, 8:32 PM

Post #17 of 110 (14513 views)
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Re: [Ron.M] Samsung CRT no power and ticking noise [In reply to]	Can't Post

When I turn off the TV, the voltage decreases very quickly and becomes 0V in 5 seconds. (I get 47V as long as the TV is on).

Does that voltage change

It turns out that we are now talking about the (above mentioned) already reached 0V voltage in 5 sec after turning the TV off, which of course goes up to 47V when I turn the TV on. :)

Ron.M
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Nov 15, 2011, 8:44 PM

Post #18 of 110 (14510 views)
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Re: [imperatormk] Samsung CRT no power and ticking noise [In reply to]	Can't Post

imperatormk;.....

Well , good news & bad news....

The good (?) news is that I'm 95% certain you have a power supply problem....
The bad news is that I need a manual to go any further...
Impossible to get without a model number...

Sorry , I can not be of any more help.... Unsure

....

Maybe someone else will come along that has more experience with Samsung TVs.... Unimpressed

...
Good Luck.... Sly

...

Later...Ron.M.... Cool

....
Veteran & Retired TV technician

imperatormk
New User

Nov 15, 2011, 9:01 PM

Post #19 of 110 (14507 views)
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Re: [Ron.M] Samsung CRT no power and ticking noise [In reply to]	Can't Post

The good (?) news

Well, it`s of course some sort of good news Laugh

I`ll do something (everything) of the following:

Try to find the manual;
Replace the capacitors which might cause the problem (have a bunch lying around);
Unsolder the flyback transformer and other major parts and check for
short between C-E;

I read somewhere that bad caps can cause a problem like this (clicking & no power), voltage lower than expected can be caused by shorted parts which increase draw and also clicking can mean that the power supply tries to start, but 'detects' a short, shuts down and then tries to start again...(I am not sure why the SMPS transformer clicks though)

Long story short, I`ll post again when I (according to me) have some valuable data. ...and now I have an opportunity to thank you for helping me to this point..........

P.S. Is the voltage I measured actually B+?

Ron.M
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Nov 15, 2011, 9:15 PM

Post #20 of 110 (14502 views)
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Re: [imperatormk] Samsung CRT no power and ticking noise [In reply to]	Can't Post

imperatormk;....

Quote

Unsolder the flyback transformer and other major parts and check for short between C-E;

Did you find a "short" between "C" & "E" ???
Thought we had that cleared up ???

Do you hear the "Clicking noise" with the horiz out transistor disconnected ???

Quote

P.S. Is the voltage I measured actually B+?

The 47 vdc you measured is for the horiz out B+....
That voltage is for the high voltage to come on...(Flyback)..
There may be a feedback from the HV transformer (Flyback) back to the SMPS to kick the 47 vdc up to about 120 vdc...
There may be other B+ voltages from the SMPS for other circuits to work...
Without a manual , this is all speculation on my part...

MY pleasure to try to help....You are VERY welcome... Smile

...

Later...Ron.M.... Cool

...
Veteran & Retired TV technician

imperatormk
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Nov 15, 2011, 9:33 PM

Post #21 of 110 (14501 views)
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Re: [Ron.M] Samsung CRT no power and ticking noise [In reply to]	Can't Post

Quote

Did you find a "short" between "C" & "E" ???
Thought we had that cleared up ???

Only when measuring the transistor while in circuit. Otherwise the transistor is completely OK, as I stated above - which means we probably have it cleared up. Removing the transistor probably wouldn't change anything (will try though), but surely I`ll find some other clue, so you or someone else can help me again :)

(This post was edited by imperatormk on Nov 15, 2011, 9:37 PM)

Ron.M
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Nov 15, 2011, 10:08 PM

Post #22 of 110 (14485 views)
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Re: [imperatormk] Samsung CRT no power and ticking noise [In reply to]	Can't Post

imperatormk;....

I got an idea.... Shocked

.....

I presume you have the original remote, right ????
IF so , look on the outside of the remote or inside the battery cover for a number...
Measure the screen size (in inches) diagonally & post info...
Give me some time to check it out as I have to go offline for awhile...

Quote

Removing the transistor probably wouldn't change anything

In this case , that is correct...

&

Quote

Do you hear the "Clicking noise" with the horiz out transistor disconnected ???

Answer appreciated...

Quote

Only when measuring the transistor while in circuit.

This is confusing me....
What is the ohms reading when the transistor IS connected ???

I should be back online in about 1~ 1 1/2 hours...

Later...Ron.M.... Cool

....
Veteran & Retired TV technician

(This post was edited by Ron.M on Nov 15, 2011, 10:13 PM)

imperatormk
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Nov 15, 2011, 10:32 PM

Post #23 of 110 (14476 views)
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Re: [Ron.M] Samsung CRT no power and ticking noise [In reply to]	Can't Post

Quote

I got an idea.... Shocked

.....

I am not surprised!

Quote

This is confusing me....
What is the ohms reading when the transistor IS connected ???

So, with no matter if the transistor is in or out, there is а dead short between C-E pins on the board. The transistor doesn`t seem to be playing any role here. Anyway, I`ll surely try the thing without the transistor and see if the clicking noise occurs again, and post the result along with the other info you requested. I`ll need some time though - probably you`ll have an answer by tomorrow. Wink

Ron.M
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Nov 16, 2011, 12:13 AM

Post #24 of 110 (14460 views)
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Re: [imperatormk] Samsung CRT no power and ticking noise [In reply to]	Can't Post

imperatormk;.....

Post #15;...

Quote

Black probe to chassis, red probe to center pin >on < the board: >47.5< KOhm
Red probe to chassis, black probe to center pin >on < the board: >47.5<KOhm

Post #19...

Quote

Unsolder the flyback transformer and other major parts and check for short between >C-E;<

Todays post #23...

Quote

So, with no matter if the transistor is in or out, there is а dead short between C-E pins >on < the board.

And you wonder WHY some of us TV guys drink a LOT !!!!.... Tongue

...
Has to be one or the other...
Dead short OR 47.5 Kohms....
Which is it ????
What is this;=>...""&#1072" ???

Furthermore;....
IF there IS a dead short from C-E ON the board , you can NOT get 47 vdc on that pin...
So something is not adding up here...
Care to esplain ??
You are using the tuner cover or the coax fitting for ground , right ???..(black probe)...

See you tommorrow...
I got to find some Prozac !!!.. Wink

...

Later...Ron.M.... Cool

....
Veteran & Retired TV technician

(This post was edited by Ron.M on Nov 16, 2011, 4:21 AM)

jts1957
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Nov 16, 2011, 1:01 AM

Post #25 of 110 (14455 views)
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What is the nomenclature "on" the horizontal output transistor? Unimpressed

-------------------------
Location: Far, Far Away

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