47 ohm resistor not working???


	FORUM HOME	SEARCH POSTS	WHO'S ONLINE	LOG IN	RULES F.A.Q.

TV Forums: TV Equipment: Projection TV Forum:
47 ohm resistor not working???

1 2

View All

Print Thread

InuGoku
New User

Sep 26, 2010, 10:59 PM

Post #1 of 27 (4396 views)
Shortcut

47 ohm resistor not working???	Can't Post

Hi, Im trying to repair a Hitachi Projection TV with a convergence problem. I found a couple of resistors that were bad and switched them out along with the IC chips.

The problem is the 47 ohm resistor gives me a proper reading out of the board but when i solder it into the board it gives me 0 ohms.

All other components give me a proper reading except for this one resistor.

Any ideas what is going on here?

jts1957
Veteran

Sep 27, 2010, 2:00 AM

Post #2 of 27 (4393 views)
Shortcut

Re: [InuGoku] 47 ohm resistor not working??? [In reply to]	Can't Post

Something's in parallel with it. Convergence yoke winding immediately comes to mind, but could be many other things.

Model & resistor location number and I can probably look them up. Unimpressed

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

InuGoku
New User

Sep 27, 2010, 3:15 AM

Post #3 of 27 (4391 views)
Shortcut

Re: [jts1957] 47 ohm resistor not working??? [In reply to]	Can't Post

I found out it was a inductor that was parallel to it but now a 33k resistor is giving me only 4-5k ohms. There are only a few transistors and diodes that are around it.

Could a transistor cause the same problem as the inductor?

Also would radio shack or home depot have replacement inductors? 120k

Here is the model of tv Hitachi 50ex20b

Thanks for any help. Smile

jts1957
Veteran

Sep 27, 2010, 5:21 AM

Post #4 of 27 (4389 views)
Shortcut

Re: [InuGoku] 47 ohm resistor not working??? [In reply to]	Can't Post

Inductors seldom go bad. In the good old days of 30 plus years ago, "maybe" RS would have stocked "some" inductors. Inductors unit of measurement is the henry (nh; mh; uh).

Pulled schematic, but you're going to have to report which circuit / LOCATION numbers of part(s) for me to find. It's like you saying a convergence amp is out. Which amp? There are three ICs each containing two amps (IK04? IK05? or IK06?).

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

(This post was edited by jts1957 on Sep 27, 2010, 5:26 AM)

InuGoku
New User

Sep 27, 2010, 6:01 AM

Post #5 of 27 (4384 views)
Shortcut

Re: [jts1957] 47 ohm resistor not working??? [In reply to]	Can't Post

Where did you get a schematic for the tv? I looked for it everywhere online and couldnt find one. Do you think you could email me a copy of it? Angelic

Ok, R 713 was the resistor that was giving me problems to begin with it was giving me 0 ohms. Then when i removed L709 (inductor) the resistor gave me its proper reading of 47 ohms. Leading me to believe that the inductor L709 was bad.

Later i found out that RF 38 a 33k ohm resistor only gives me 4-5k ohms. Which leads me to believe that some other component is causing the problem for RF38 the same way L709 did for R713. I looked at the things that are around RF38 and i only see a capacitor, some transistors, a few diodes, and more resistors. So im not sure what could be causing the problem. Crazy

If your looking at the board from the back to the front of the TV then these components are right at the beginning of the back of the board before the flyback transformer.

Thanks again for your help.

jts1957
Veteran

Sep 27, 2010, 7:16 AM

Post #6 of 27 (4382 views)
Shortcut

Re: [InuGoku] 47 ohm resistor not working??? [In reply to]	Can't Post

Try searching by the chassis number. Many different model numbers may use the same chassis number.

If you have a convergence problem, what are you doing in the CRT heater and high-voltage feedback circuits?

Convergence ICs, bias resistors (changed value/open) and +/- VCC (open pico fuses) to the ICs, are the usual causes.

Don't mess with the do-dads on the CRT necks nor the settings of ANY control on the "Board 'O Pots" (convergence correction PCB). IF no one's been messing with the TV, when you've replaced ALL the defective parts, it should ONLY require CUSTOMER convergence adjustments.

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

(This post was edited by jts1957 on Sep 27, 2010, 5:25 PM)

InuGoku
New User

Sep 27, 2010, 8:14 AM

Post #7 of 27 (4378 views)
Shortcut

Re: [jts1957] 47 ohm resistor not working??? [In reply to]	Can't Post

Well, after i replaced the resistors and the IC that were on the heatsink i put everything back together and i had no picture. I pressed the menu button to see if i could see anything and i couldnt see a thing. So i searched online and i found out that the flyback transformer solder points could have been cracked due to the fact that the solder they used had no lead in it.

After resoldering the points i checked the resistors just to make sure nothing was wrong and that is when i noticed that something was wrong with the resistors values when installed on the board.

jts1957
Veteran

Sep 27, 2010, 8:42 AM

Post #8 of 27 (4377 views)
Shortcut

Re: [InuGoku] 47 ohm resistor not working??? [In reply to]	Can't Post

If your original problem was the set would run but had a "3-D" picture and after replacing the parts you listed now it does not fire up, something went wrong.
Anything from a solder "splash" to a solder bridge, damaged foil traces, plugs left unplugged, plugs plugged into the wrong socket, pin(s) of a socket bent, etc.

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

InuGoku
New User

Sep 27, 2010, 5:08 PM

Post #9 of 27 (4373 views)
Shortcut

Re: [jts1957] 47 ohm resistor not working??? [In reply to]	Can't Post

Yeah the original problem was the 3-D picture. I guess i messed up somewhere.

What do you recommend i should do? Finding the problem with the resistor will not fix my problem?

jts1957
Veteran

Sep 27, 2010, 5:22 PM

Post #10 of 27 (4372 views)
Shortcut

Re: [InuGoku] 47 ohm resistor not working??? [In reply to]	Can't Post

Recheck your work. Use a magnifier of some kind. Examine the WHOLE board. Remember molten solder will drip DOWNWARD.

Quote

the 47 ohm resistor gives me a proper reading out of the board

WHAT resistor problem?

If you put a wire across both leads of a two-legged part, you WILL "read" the WIRE!

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

InuGoku
New User

Sep 27, 2010, 9:14 PM

Post #11 of 27 (4366 views)
Shortcut

Re: [jts1957] 47 ohm resistor not working??? [In reply to]	Can't Post

Sorry for my misuse of words and unfamiliarity with certain things. I guess its not a "resistor" problem since the resistor is good.

I cant find anything physically wrong with the board. Im just going to buy the inductor and put it on to see what happens.

What if I were to put a higher rated resistor like 100+k so that it reaches the appropriate 33k?

jts1957
Veteran

Sep 28, 2010, 2:31 AM

Post #12 of 27 (4362 views)
Shortcut

Re: [InuGoku] 47 ohm resistor not working??? [In reply to]	Can't Post

May as well connect one end of the inductor to one side of AC plug and the second end of the inductor to the other side of AC plug. Crazy

Bobby pin in the electric socket - blows breaker / burns down home.

I'd highly recommend taking the set in to a qualified servicer.

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

InuGoku
New User

Sep 30, 2010, 11:31 PM

Post #13 of 27 (4343 views)
Shortcut

Re: [jts1957] 47 ohm resistor not working??? [In reply to]	Can't Post

Hey, I got the tv to work but it still has the convergence problem. I ordered this IC http://tigerdirect.partsearch.com/Part/Hitachi+Ltd/Hitachi/50EX20B/Hitachi+Ltd/Hitachi/2373343/New.aspx
but i guess i have to replace the other one next to it too.

I looked all over the internet trying to find the other IC but had no luck. I dont even have the part number.

Would it be too much to ask if you could get the part number from your schematic? I tried to call Hitachi and TigerDirect for information but had no luck with that either.

jts1957
Veteran

Sep 30, 2010, 11:49 PM

Post #14 of 27 (4341 views)
Shortcut

Re: [InuGoku] 47 ohm resistor not working??? [In reply to]	Can't Post

http://www.mcmelectronics.com/product/STRM6511

What is the "location number" of "IC?"

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

InuGoku
New User

Oct 1, 2010, 12:00 AM

Post #15 of 27 (4339 views)
Shortcut

Re: [jts1957] 47 ohm resistor not working??? [In reply to]	Can't Post

Wow! thanks! I believe its D901. It seems weird because i thought D was for Diode but that is the only number i see on the board that would respond the IC.

It is right in the middle of C904, C905, C906, and D902.

Its a 4 pin chip and it has these letters and numbers on it.

(the "S" isnt really an S the middle section of the S is a straight line.)

S D3SBA60 6N

(the 6 has a line on top of it and the N has a line under it.)

jts1957
Veteran

Oct 1, 2010, 12:54 AM

Post #16 of 27 (4332 views)
Shortcut

Re: [InuGoku] 47 ohm resistor not working??? [In reply to]	Can't Post

It is NOT involved in your problem. Wink

D901 2342061 D3SB(A)60

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

InuGoku
New User

Oct 8, 2010, 2:08 AM

Post #17 of 27 (4312 views)
Shortcut

Re: [jts1957] 47 ohm resistor not working??? [In reply to]	Can't Post

Hey, I finally got the part from UPS today and swapped the IC, but the tv still has the convergence problem. I cant even control the red + in the convergence menu.

Could it be a resistor that blew out that needs to be changed? Just to make sure does this TV only have1 convergence IC? What do you think could be causing this now?

Im gonna double check it now but i wanted to get some extra help from a more knowledgeable source.

jts1957
Veteran

Oct 8, 2010, 3:01 AM

Post #18 of 27 (4309 views)
Shortcut

Re: [InuGoku] 47 ohm resistor not working??? [In reply to]	Can't Post

So far your efforts seem to be concentrated in a non-defective power supply. Are you any kin of "DummyDerrick" (no offense intended)?

Quote

Which amp? There are three ICs each containing two amps (IK04? IK05? or IK06?).

The usual course of action is to get the three ICs. While the ICs are removed and floating one end, if necessary, the value of each bias resistor is checked to be sure it is in tolerance. Any found out of range are replaced. Finally the three new ICs are installed being sure there is sufficient heat transfer compound and that each soldered pin is not bridged accidentally to its neighbor.

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

(This post was edited by jts1957 on Oct 8, 2010, 3:05 AM)

InuGoku
New User

Oct 8, 2010, 3:22 AM

Post #19 of 27 (4303 views)
Shortcut

Re: [jts1957] 47 ohm resistor not working??? [In reply to]	Can't Post

umm... im not sure what DummyDerrick is. I only ordered one IC "I901" http://www.mcmelectronics.com/product/STRM6511 the one you helped me find a cheaper price on. I didnt know that there was more than one Convergence IC. Do you know what other ones i need to get?

(This post was edited by InuGoku on Oct 8, 2010, 3:30 AM)

jts1957
Veteran

Oct 8, 2010, 3:32 AM

Post #20 of 27 (4301 views)
Shortcut

Re: [jts1957] 47 ohm resistor not working??? [In reply to]	Can't Post

In Reply To

So far your efforts seem to be concentrated in a non-defective power supply. Are you any kin of "DummyDerrick" (no offense intended)?

Quote

Which amp? There are three ICs each containing two amps (IK04? IK05? or IK06?).

DummyDerrick:http://www.tv-forums.com/...gence_repair_P60484/ Pg. 2 onward

Location # Part # Description
IK04 2003191 STK4274
IK05 2003191 STK4274
IK06 2003191 STK4274

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

(This post was edited by jts1957 on Oct 8, 2010, 3:46 AM)

InuGoku
New User

Oct 8, 2010, 3:47 AM

Post #21 of 27 (4294 views)
Shortcut

Re: [jts1957] 47 ohm resistor not working??? [In reply to]	Can't Post

Man, I feel like such an idiot. There was no need to buy

http://www.mcmelectronics.com/product/STRM6511

You were telling me from the beginning that it was something else. I saw these 3 big chips that were on the side of the board. Its STK 4274.

AHHHHHHHGGGGGGGGHHHHHHHHHH!!!!!!!!!!!!!!!! Mad

I hope i can return the other part that i got and get credit for the 3 new IC's that im gonna order.

I actually received 2 of the STR M6511. I think they gave me 2 by accident. They dont come in pairs of 2 right? will they take my item back?

jts1957
Veteran

Oct 8, 2010, 4:10 AM

Post #22 of 27 (4290 views)
Shortcut

Re: [InuGoku] 47 ohm resistor not working??? [In reply to]	Can't Post

In the 1st post of this thread you stated: "Hi, Im trying to repair a Hitachi Projection TV with a convergence problem. I found a couple of resistors that were bad and switched them out along with the IC chips."

If you don't tell us anything to the contrary, we'll presume you know what you are talking about. Wink

Can't hurt to ask. Probably the one you did NOT solder in/use can be returned. Check the invoice for quantities/return policy.

You may want to recap:
Starting symptom...
Action taken...
Symptom now.

Can action taken be reversed?

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

(This post was edited by jts1957 on Oct 8, 2010, 4:20 AM)

InuGoku
New User

Oct 8, 2010, 4:23 AM

Post #23 of 27 (4284 views)
Shortcut

Re: [jts1957] 47 ohm resistor not working??? [In reply to]	Can't Post

Yeah i kind of messed up from the beginning.

Here is the order information.

Order Line Items
1 STRM6511 - SANKEN IC 7-PIN ZIP SMPS CNTRLLR VOLTAGE MODE
$11.29
$11.29

It says "order 1"

and here

http://www.mcmelectronics.com/product/STRM6511

It says "Qty 1"

Right? or am i missing something.

One thing I DO KNOW is that when i opened the package, There were "2" STK M6511 chips that were stuck together.

Anyway THANK YOU!!!!!!! for all of your help. I learned a lot trying to fix this thing and now that i saw what i really needed I am confident i will be able to fix it. Ill keep you updated when i get the parts and put them in. Smile

jts1957
Veteran

Oct 8, 2010, 4:32 AM

Post #24 of 27 (4282 views)
Shortcut

Re: [InuGoku] 47 ohm resistor not working??? [In reply to]	Can't Post

You got a free one. Smile

You may want to recap:
Starting symptom...
Action taken...
Symptom now.

Can action taken be reversed?

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

(This post was edited by jts1957 on Oct 8, 2010, 4:32 AM)

InuGoku
New User

Oct 13, 2010, 1:25 AM

Post #25 of 27 (4265 views)
Shortcut

Re: [jts1957] 47 ohm resistor not working??? [In reply to]	Can't Post

Edit #3

It WORKS!!!!! HOORAY!!!! i just needed to let it warm up.

Thanks again jts1957. Thank you soooo much for being patient with me. I could not have done it without you. Smile

(This post was edited by InuGoku on Oct 13, 2010, 2:32 AM)

1 2

View All

Print Thread

Search for (options)

- Page loaded in: 0.19 s on (CGI/1.1)