Samsung 2493 HM issue

[zulururu]

Re: Samsung 2493 HM issue

First of all, thank you very much for the explanation on the resistors, and the more I look at my 487 ohm resistor, the more I see an 4R7 ! So this one seems to be good !

I measured the resistance between the circled components, I labelled them from the lower left corner 1, then clockwise 2 is the to pin, 3 is the right one.

For the component circled at the top of the picture, I've found:

between pins 1 and 2: 21300 ohms
between pins 1 and 3: 4 ohms
between pins 2 and 3: 21300 ohms

For the component just under the first one

between pins 1 and 2: no reading (1 on the left of my DMM screen)
between pins 1 and 3: 9960 ohms
between pins 2 and 3: no reading (1 on the left of my DMM screen)

Unfortunately I don't see any letter on these components, however I don't have a magnifier :-(

[PlainBill]

Re: Samsung 2493 HM issue

First of all, thank you very much for the explanation on the resistors, and the more I look at my 487 ohm resistor, the more I see an 4R7 ! So this one seems to be good !

I measured the resistance between the circled components, I labelled them from the lower left corner 1, then clockwise 2 is the to pin, 3 is the right one.

For the component circled at the top of the picture, I've found:

between pins 1 and 2: 21300 ohms
between pins 1 and 3: 4 ohms
between pins 2 and 3: 21300 ohms

For the component just under the first one

between pins 1 and 2: no reading (1 on the left of my DMM screen)
between pins 1 and 3: 9960 ohms
between pins 2 and 3: no reading (1 on the left of my DMM screen)

Unfortunately I don't see any letter on these components, however I don't have a magnifier :-(

4 Ohms would mean a base-emitter short. That would indicate a problem, unless it's deliberate. More on that later.

I've looked at four pictures; in some of them I swear I can see letters, in others - nothing. I also cannot be sure just what the connections are; in some of them the lower transistor is the only one connected; in others both are. You know what that means, don't you.

Yes, I've marked up the picture again. Pin 11 is marked with a crudely drawn black arrow. There are two areas of interest.

To the right is an area circled in red. At the top of the circle I have placed a red dot on one point. Check if that point is connected (less than 5 ohms) to pin 11. If it is not, ignore that area.

Below pin 11 I have circled an area in blue. Looking at the upper of the two transistors, it appears there might be a connection between pins 1 and 3. Is that real, or is that my imagination? If it's real, we can stop looking. If it was my imagination, we (you) have more work ahead. I've marked the collector of the lower of the two transistors with a blue dot. Is that connected to pin 11? if it is, is there any connection between the two transistors?

Ignore the area circled in white. That was a momentary flight of fancy.

Your profile does not indicate where you are. If you are in the USA, Harbor Freight sells a good magnifying glass for $2.00

PlainBill

[zulururu]

Re: Samsung 2493 HM issue

I did my homework, First of all, I found a magnifying glass at work !!!

You are right (as usual ) there are letters on the 2 transistors, on the one on top, I can read "W5", on the bottom one, I think I read "P" or "1P".
Excuse my ignorance but no, I don't know what that mean when there are connections in some pictures and not on others !

I measured the resistance between the red point and pin 11 and it doesn't seems to be connected (1 on the left side of my DMM screen in every range mode)

I also do not find any connections between pins 1 and 3 of the upper transistor, however between the blue dot and pin 11, I found a resistance of 4 ohms.

Using the DMM again, I found a resistance of 4 ohms between pin 1 of the upper transistor and pin 1 of the lower transistor so somehow, there are connected together !

[PlainBill]

Re: Samsung 2493 HM issue

I did my homework, First of all, I found a magnifying glass at work !!!

You are right (as usual ) there are letters on the 2 transistors, on the one on top, I can read "W5", on the bottom one, I think I read "P" or "1P".
Excuse my ignorance but no, I don't know what that mean when there are connections in some pictures and not on others !

I measured the resistance between the red point and pin 11 and it doesn't seems to be connected (1 on the left side of my DMM screen in every range mode)

I also do not find any connections between pins 1 and 3 of the upper transistor, however between the blue dot and pin 11, I found a resistance of 4 ohms.

Using the DMM again, I found a resistance of 4 ohms between pin 1 of the upper transistor and pin 1 of the lower transistor so somehow, there are connected together !

I suspect your DMM leads have an unusually high resistance. Try shorting the probe tips together with the meter on the lowest resistance range and see what reading you get.

That is a peripheral issue, however. I've taken this as far as possible. I have been unable to even tentatively identify either of the transistors. Between the lack of a schematic and the inherent problems identifying semiconductors by their marking codes, I am at a dead end. I THINK the MC33067P has failed, but I can't be sure.

I see two possible approaches. An eBay seller in Malaysia has the MC33067P available for $8 + $6 shipping. Also, several sellers in China have the complete (used) power supplies for $54 with free shipping.

PlainBill

[pamr4]

Re: Samsung 2493 HM issue

Please measure the 3 resistors placed around the big cap (i think is 82micro 400-450V?). The resistors are supose to be noted on PCB something like RM801, bla bla. Post readings.

[zulururu]

Re: Samsung 2493 HM issue

I shorted my DMM probe and I read 0.4 ohm but I realised I made a mistake when I gave you some value of 4 ohms, it was a misreading and was actually 0.4 ohm ! Sorry about that !

I measured all the resistors around the big capacitor, here are the results:

RB801 reading 100060 OHMS vs colour code 10*10000 +/-5% OK
RB802 reading 97600 OHMS vs colour code 10*10000 +/-5% ok
RM801s reading 32.7 OHMS vs colour code 330 /10 ok
RM801 reading 0.6 OHMS vs colour code 228*0.1 problem ?
RB808 reading 2.4 OHMS vs colour code 2OHMS OK
RB803 reading 47.4 OHMS vs colour code 47 OHMS OK

Do you think the problem I have with RM801 is ue to my cheap DMM ?

My goal if possible is to find the exact faulty component so I guess I will order a MP33067P, I found one here:

http://www.futurlec.com/cgi-bin/sear...earch=MC33067P

for 2$ + 4$ shipping, can you confirm that's the right one ??
If yes, I will order it, the shipping will take 2 weeks !!

Thanks you all for your help

[PlainBill]

Re: Samsung 2493 HM issue

I shorted my DMM probe and I read 0.4 ohm but I realised I made a mistake when I gave you some value of 4 ohms, it was a misreading and was actually 0.4 ohm ! Sorry about that !

I measured all the resistors around the big capacitor, here are the results:

RB801 reading 100060 OHMS vs colour code 10*10000 +/-5% OK
RB802 reading 97600 OHMS vs colour code 10*10000 +/-5% ok
RM801s reading 32.7 OHMS vs colour code 330 /10 ok
RM801 reading 0.6 OHMS vs colour code 228*0.1 problem ?
RB808 reading 2.4 OHMS vs colour code 2OHMS OK
RB803 reading 47.4 OHMS vs colour code 47 OHMS OK

Do you think the problem I have with RM801 is ue to my cheap DMM ?

My goal if possible is to find the exact faulty component so I guess I will order a MP33067P, I found one here:

http://www.futurlec.com/cgi-bin/sear...earch=MC33067P

for 2$ + 4$ shipping, can you confirm that's the right one ??
If yes, I will order it, the shipping will take 2 weeks !!

Thanks you all for your help

That's the one. Congratulations on finding it at a very reasonable price.

PlainBill

[zulururu]

Re: Samsung 2493 HM issue

Excellent ! I just ordered it for 5.8USD postage include !
I will let you know if that fixed it !
Thanks you again !

Gilles

[pamr4]

Re: Samsung 2493 HM issue

Please confirm that the big cap is 82micro. If it is, measure the voltage across the legs of the cap (10 sec) and post reading.

[PlainBill]

Re: Samsung 2493 HM issue

Please confirm that the big cap is 82micro. If it is, measure the voltage across the legs of the cap (10 sec) and post reading.

Already done. Note the results in post 21.

PlainBill

[pamr4]

Re: Samsung 2493 HM issue

Sorry for missing that PlainBill.

[PlainBill]

Re: Samsung 2493 HM issue

Sorry for missing that PlainBill.

'De Nada.'

Now could you explain what you were referring to in your post #45? I've been going round and round these supplies, and between the lack of a schematic, obscured traces, inadequate test gear, and obtuse datasheets, it's been difficult to figure out where the actual failure lies.

PlainBill

[pamr4]

Re: Samsung 2493 HM issue

'De Nada.'

Now could you explain what you were referring to in your post #45? I've been going round and round these supplies, and between the lack of a schematic, obscured traces, inadequate test gear, and obtuse datasheets, it's been difficult to figure out where the actual failure lies.

PlainBill

Analogy with common power supply failure like 245BW. (when you don't figure it out, excalate the problem, search document findings, etc.

[PlainBill]

Re: Samsung 2493 HM issue

Analogy with common power supply failure like 245BW. (when you don't figure it out, excalate the problem, search document findings, etc.

You were referring to the BN44-0173A power supply. This is a BN44-00195A supply. The standby SMPS controller in the BN44-0173A derives startup power through a series of resistors. The standby SMPS controller in the BN44-00195A is an integrated design, and is connected directly to the rectified mains voltage; it derives startup power internally. What is more, it is working, and the main SMPS controller is receiving power.

PlainBill

[zulururu]

Re: Samsung 2493 HM issue

Hello all,

Just to let you know that I still didn't receive my SMPS controller, so taht's why I didn't update that post yet ! It should arrive soon hopefully !

[PlainBill]

Re: Samsung 2493 HM issue

Hello all,

Just to let you know that I still didn't receive my SMPS controller, so taht's why I didn't update that post yet ! It should arrive soon hopefully !

Thanks for the information. We're waiting to find out if that will fix it.

On a related subject, what is printed on the cap labeled 'Long Blue Cap' in the attached picture?

PlainBill

[zulururu]

Re: Samsung 2493 HM issue

On mine it's written on the top:
12 NJ 630v
some kind of a reversed "C" 4 MMKP
On the side of it I can read:
PILKOR
WK0747

I hope this help !

[PlainBill]

Re: Samsung 2493 HM issue

On mine it's written on the top:
12 NJ 630v
some kind of a reversed "C" 4 MMKP
On the side of it I can read:
PILKOR
WK0747

I hope this help !

Yes, it does. Thank you. Pilkor is the manufacturer, it's a 12nF, 630V, 5% cap.

Now, the $64 question: Does your DMM have a capacitance range? This cap has an equivalent in the BN44-0173A power supply, and is known to fail.

PlainBill

[alexanna]

Re: Samsung 2493 HM issue

The monitor I had where that capacitor failed was the BN44-0173 Board, there was no obvious bloating or burning on the outside of the cap. After removal from the board there was some very slight discoloration of one of the pins where it went into the plastic, it was very hard to see.
If your meter does not have a capacitance reading ability, and buying a new meter is out of the question.
There would be nothing wrong with having someone checking it for you, any heating air condition technician, or if you have small local hardware store ask them to help you out, I would suspect the cost to be minimal if any.

[zulururu]

Re: Samsung 2493 HM issue

Is it a question for me ?? if yes, my DMM doesn't have a capacitor range .....sorry !