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Soldering Problem

philadelphia1

Jun 25, 2016
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Hello,

I'm currently working on my televisions IC convergence board and can't get the solder to stick to Pin #3. I don't know if there was a pad there or not? Or if its just oxidized. I did try to lightly sand it with a fine nail file and then cleaned it ups with some isopropyl alcohol and got the same results....solder wont stick. Have a look at the attached picture, it's the 3rd pin I'm having trouble with. It's circled in red. Hope I remedy this situation cause I really like this TV.

Any help you guys can provide is greatly appreciated!

Regards,

-Shawn in Philly

Convergence ic pin #3.jpg
 

BobK

Jan 5, 2010
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Looks to me like the pad is gone. But the other pins nearby look like bad solder connections as well. What kind of solder are you using? Are you using extra flux?

Bob
 

philadelphia1

Jun 25, 2016
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Hello there Bob,

In the picture ONLY the 1st two pins are soldered, then when I hit the 3rd I had trouble and took the picture.

Later that evening, I was able to successfully solder all of the other pins, (which the picture does not show) It went quick.....nice and smooth.....no problems, just that darn 3rd pin wont take. I'm not sure how to use extra flux? If the pad is gone how can I remedy my problem?

Here are some pics of the tools I'm using....solder.jpg

solder desolder.jpg
 

73's de Edd

Aug 21, 2015
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Sir Shawn . . . . . . .

IC8001 and IC8002 . . . . .aka . . . . . STK392-560

How lucky can you get!

Seems like you don't . . .and won't . . .have to worry about pin 3, as it is totally not being involved in your convergence circuitrys scheme of operation.
That pin 3 just floats . . .unconnected !
Now if you were using this device in its DESIGNED function, it might be a factor, as it is a mute activation function.
Also . . . you DO realize that these high powered audio amplifiers are being repurposed . . . . . in this case . . . . . . of Sony using it for RGB hoz and vertical yoke drivers, in its convergence circuitry.

Associated Sony schema snippet:




2011-06-05_132415_untitled_-_5.jpg




73's de Edd
 
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(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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Wow.

Let me assume the pin was soldered when you removed the chip?

If so, you may have dodged a bullet.

However, I recommend you improve your technique somewhat before trying this again.
 

duke37

Jan 9, 2011
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Lead free solder needs a higher temperature than eutectic tin/lead solder.
 

philadelphia1

Jun 25, 2016
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Sir Shawn . . . . . . .

IC8001 and IC8002 . . . . .aka . . . . . STK392-560

How lucky can you get!

Seems like you don't . . .and won't . . .have to worry about pin 3, as it is totally not being involved in your convergence circuitrys scheme of operation.
That pin 3 just floats . . .unconnected !
Now if you were using this device in its DESIGNED function, it might be a factor, as it is a mute activation function.
Also . . . you DO realize that these high powered audio amplifiers are being repurposed . . . . . in this case . . . . . . of Sony using it for RGB hoz and vertical yoke drivers, in its convergence circuitry.

Associated Sony schema snippet:




2011-06-05_132415_untitled_-_5.jpg




73's de Edd

Hello there my friend from the GREAT BIG state of TEXAS! Thanks for the reply and your research. I was thinking the same thing by looking at the schematic but wasn't sure. I was indeed lucky! (but that was short lived.....i'll explain in a follow-up post.)

I'm a novice at best when it comes to this side of electronics (soldering and understanding schematics)... I'm a computer tech by trade. Nonetheless, I'm eager to learn form wizards like you and the others on this forum.

Very interesting, if I understand you correctly these stk's were originally designed for a completely different application then retroactively adapted for the convergence on projection screen televisions? Is that that a bad thing? I did not know this.

I also understand that these IC's fail quite often, the internet and various forums are littered with hundreds of posts mentioning these fail in projection screens. I'm suspecting that heat is taking most of them out more often than not.
 

philadelphia1

Jun 25, 2016
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Wow.

Let me assume the pin was soldered when you removed the chip?

If so, you may have dodged a bullet.

However, I recommend you improve your technique somewhat before trying this again.

Hi there Steve,

Pin #3 was soldered when I removed the chip. I did indeed dodge a bullet but the SOB turned around and hit me smack dab in the ass. (i'll explain in a follow-up post.) You're 100% correct I do need to vastly improve my technique before continuing this project. I have many old pcb's for junked electronic parts that I kept around for the capacitors etc, I will practice on them.
 
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(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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desoldering components is a skill. If you are just removing them to replace them, clipping off the leads from the component then removing the pins one by one is an easier technique.

However if you want to reuse the component and not damage the board, you need to practice and possibly get told to assist you.

If you're using solder braid, get a good brand. It makes more difference than you would believe.

a vacuum desoldering tool can help, but it's no panacea, you still need practice. These tools can lead to damaged boards I'd not used with care.

for general use I would use tin/lead solder because it's easier.
 

73's de Edd

Aug 21, 2015
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Sir philadelphia1 . . . . .


I am just hoarding my "60/40" solder, in case the " no lead advocates " make it harder . . .and more expensive . . . . to get in the future.


I'm suspecting that heat is taking most of them out more often than not.

My multi decades of experience and failure analysis reveals:

A vehicle of silicone oil or / and silicone grease mixed with a solid oxide agent is being the heat transfer medium used between the semiconductors heat sink tabs/plate and the MASSIVE heat sink associated with it.
With time, the very center of the semis heat sink plate receives the least cooling and the silicone migrates laterally outward.
That leaves a deposit of minimally wetted oxide powder, that extra heat drives the silicone component even further away from the central region.The central region ends up as a minimally heat conducting dry oxide area.
Finally that overheated central area of the semi is subject to thermal induced failure..

If you are heavily involved in the "puter design aspect, you will find the same situation involved with the main CPU and its cooling.
An infrared spectrometry of the device and its heatsinking along with increased run temperature will reveal the same onset of reliability issues as well as some real "squirrely " side effects showing up.
They are a bit more involved in the heat paste formulation, with it advancing up to to a silver "dust" heat carrying medium.

Thassssit . . . .


73's de Edd
 
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philadelphia1

Jun 25, 2016
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So, after thinking I dodged a bullet... a second one was fired and struck me straight in the ass...lol. (please excuse my French, I apologize, not proper)

The problem I have now is closely related to the original, this time with the power supply board. When the convergence IC's failed, it took out a 5 amp pico fuse and a 1000 μF capacitor.

While desoldering the pico fuse (PS5001) once again, I think I stripped a pad on ps5001? I'm not sure? Please see photo at the bottom of this post.

When I try to solder ps5001 the solder flows upward toward another solder point on the board and I'm not sure if its supposed to do that? I don't think so though. Perhaps someone can tell by looking at the schematic and the picture of my post? I'm almost sure they were separate. Again not sure though.

I appreciate your time and patience with this NEWBIE.

Like I mentioned in earlier posts, I'm barely a novice and very eager to learn.... also thankful that you folks have the patience and time to work with me. It's appreciated!

I uploaded a schematic picture pertaining to the power board and ps5001.

Also, a link to the service manual. The power board is on page 57. http://www.manualslib.com/manual/695529/Sony-Kp-51ws510.html

Thanks so much for your help guys!

-Shawn in Pa

power damage.jpg

DSC00731.JPG
upload_2016-6-28_0-21-47.png
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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You're probably leaving the soldering iron on the joint too long, or digging with it. This can lead to pads being removed.
 

73's de Edd

Aug 21, 2015
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Sir Philadelphia 1 . . . . . . .


You do know that you are working with a probably "UNOBTANIUM " / NLA circuit board . . .don't you ?

After looking at your component extraction prowess . . . . I believe that EVERY foil pad on the board is quaking and saying . . . . .
Get the hell out of here ! . . . "der TERMINATOR isht comink ! ! ! "

The fail path layout is given on the large layout while the VERY bottom schema relates to the assigned color coding of the involved foil paths of the fuse.
We have a given that the MINUS 22VDC supply is first filtered by C5018 and has to make an inclusive circuit path from its NEGATIVE terminal over to the NEGATIVE terminal of C5027.
So take ohmmeter in hand and spike one probe into C5018 negative and work down the foil trail that I have marked in PURPLE, with its lowest point looking like it connects to one lead of the fuse.
The other lead of the fuse looks like it goes down to L5008 via the LIME GREEN path until it reaches the very end that I have stopped at.
Go to the other C5027 caps negative terminal and see it routed up the BLUE path until it reaches its uppermost position.

Now somewhere in this LOUSY layout drawing which SONY has given us, there should be a JUMPER WIRE connecting those two routes . . .End of the BLUE line at its top to the bottom of the LIME GREEN line .
Ohm between the two to confirm, if they are being connected together, if so all is well.

Then you just need to go back to the Fuse area and see the two foil paths that the fuse needs to be connected between . . . . less its NOW destructed original pad.

I would now like to castigate you on your poor / destructive parts extraction expertise . . . .to which you reply . . ."BUT . . .won't that HURT ?" . . . . .to which I reply . . .no . . .I said . . . . . c a s t i g a t e !

When you were pulling that defective . . .. e.g. . . sacrificial . . .STK unit . . . .you should have loosened it from the heat sink and flexed it to its limits for 148 and 'leben nineteenths times, until metal fatigue had then popped all of its 18 connector pins.
( CUZ . . . .even micro-mini dikes don't get into that cramped area too well !)
THEN add a drop of fresh solder to a pins solder pad, for enhanced thermal transfer, and then pull out the pin from the other side, with a pair of needlenose . . . only 17 left to go !.

If that was a leaded / pigtail fuse you should have had a small pocket or jewelers screwdriver under one of its leads, close to the feed thru hole on the component side of the board.
The screwdriver tip is against the pcb so you basically have a controllable lever to lift the lead out . . .AFTER . . . you place that one drop of fresh thermal enhancing solder to the pad
Then the whole blob just liquefies . . .and you lever out the lead.
Straighten the lead and then you brace a closed fist against the boards component side while the finger and thumb pull the lead out, after solder melting its foil pad.

Good thing that we did not have to see much below our involved area, as Sony has made an unreadable double overlay on the very bottom of the page.

Thasssit . . . . .

Techno Referencing:

KJZgVad.png



73's de Edd
 
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philadelphia1

Jun 25, 2016
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DSC00731111111.jpg Wow, this is way out of my league...if you want to duck and run now it's ok. Like I had mentioned I wouldn't even call myself a novice. lol. I have to take baby steps.

Being that there is currently no fuse in ps 5001 shall I still test with the DMM? If so shall I set the meter to Ohms and test while the power is off right? What will the meter read while doing so? I have a new pico but when I try to solder ps5001 the solder flows upward toward another solder point on the board and I'm not sure if its supposed to do that?
 
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philadelphia1

Jun 25, 2016
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Hello there Mr. 73's de Edd,
You do know that you are working with a probably "UNOBTANIUM " / NLA circuit board . . .don't you ?

After looking at your component extraction prowess . . . . I believe that EVERY foil pad on the board is quaking and saying . . . . .
Get the hell out of here ! . . . "der TERMINATOR isht comink ! ! ! "

I got a good laugh from this, I like your sense of humor coupled with that dash of sarcasm.

Thanks for the soldering tips concerning the future removal of my stk's! Excellent idea. See.....I'm learning? I think?
 

73's de Edd

Aug 21, 2015
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Sir philadelphia1. . . . . . .

O.K. then maybe we can dumben my prior info down a bit . . . possibly then being one level up from:
"I do not like green eggs and ham. I do not like them, Sam-I-Am."

Referring to your photo just above, lets just see if that top portion circular foil land that is being seen within the RED circle is being
another viable position for the top connection of the fuse.
Its for sure, that you only see traces of copper left, where the old foil circle used to be.

You can see the marking for C5017 up above and should be able to see the foil path pass down and get close to that circle or that
foil land within the top of the RED circle, actually might be a direct connect.

No power to the unit . . .take ohmmeter in hand and switch to its LOWEST ohms scale . Look at the display . . .that's what an OPEN circuit reads as.
Short the test leads probes together thats what a short or very low resistance connection looks like.

Place one test prod to the C5017 negative connection . . . . .place the other prod to our connection, within the top of the RED circle.
If that is passing the "shorted" test that will be the top connection of the fuse.If not you will have to seek out the PURPLE LINE path.

Move down to C5027 negative terminal and either visually trace the foil path up to as close as it goes to the RED circle, or confirm by the use of
your ohmmeter.
That should constitute of the BLUE and LIME GREEN path with a wire jumper joining them.
That uppermost point that has a solder blob will be the other connection point for the bottom lead of the fuse.
Considering that you have a full lead length fuse, tin its leads up from the ends stopping 1/3 of an inch from its body to prevent any heat damage.
As per your fuses bottom land . . . . . you may already know where its solder pad and associated hole is . . . if it wasn't damaged ?
If so it will just be standard replacement procedure on the bottom fuse lead, using same hole and solder land.
The top fuse lead will require a pass thru the hole and then a slight extension of the lead with a right angle bend to permit the lead to reach up to another substitute solder pad, that makes the same circuit path.
Then, that joint is reflow soldered.


73's de Edd
 
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skenn_ie

Sep 7, 2009
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For flux, with corroded pins/pads, I use a white paste called Powerflow, by FRY. I have never come across a more effective flux. It works well at cleaning soldering iron tips too, just apply solder immediately after use.. However, I can't comment on possible corrosive effects over time, so clean well after use.
 

73's de Edd

Aug 21, 2015
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In that products endeavor in disguise within its MSDS postings info.
I am HEAVILY in suspect if it's white coloring aspect, as being content
of my earlier mentioned ammonium chloride.

It has been used for the facilitating of cleaning soldering irons w..a..y
back, starting in the 1920's.
It was known to the layman . . . .non chemist . . . .as Sal ammoniac.


73's de Edd
 
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philadelphia1

Jun 25, 2016
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Hello there 73's de Edd & others on this great forum,

I want to apologize for a prolonged absence since my last post. I've been so unbelievably busy at work and with family, I haven’t had a minute to work on my home project; that you folks have been so kind and generous to offer your time and wisdom to help me. Please KNOW that it's APPRECIATED !

I spent some time reflecting on the previous posts and realized what 73's de Edd was instructing me to do wasn't that complicated after all.

At first, I was a little intimidated and overwhelmed as per the instructions and how to proceed, (keep in mind that I'm a NEWBIE) but the more I contemplated what it was that you wanted me to do, a light bulb went "ON" (although DIMLY lit) I proceeded. I appreciate that you took the time to color code the exact foil path and procedure to follow. That helped so much !

So.... I laughed my ass off at this:

"O.K. then maybe we can dumben my prior info down a bit . . . possibly then being one level up from:

"I do not like green eggs and ham. I do not like them, Sam-I-Am."


-That was a good one... very clever,, had a good laugh...and the revision helped too!


Here's what I did:

So being there was what appeared to be less than a quarter of the foil pad left at PS5001's damaged section I decided to solder

(most would say..."der TERMINATOR HAS ARRIVITH".. and HE cometh wit thy ARC WELD)

and it traced to another component of which I’m not sure if they are supposed to be bridged? So I decided to go with it anyway to see what happens. It appears as if the quarter pad left at PS5001 is being shared with another component located at L5008? It's difficult to tell by looking at the schematic in the service manual but I have an idea these two paths are linked either by foil (now damaged) or NOW by my excellent soldering skills resulting in a bridged connection.

bridged.jpg bridged to.jpg

Nevertheless, the 5 amp pico has been holding for over a week now and I’m assuming if that connection WASN'T supposed to be bridged it would of blown the fuse relatively quickly?

As per 73's ed Edds initial instructions.... I busted out my digital multi-meter and traced the foil path from the negative terminal at capacitor C5018 down to the lead of the 5 amp pico (PS5001) and got no resistance. Then I tested from the opposite lead of the pico down to the negative terminal of the capacitor located at C5027 and too got no resistance. I also tested for continuity and for those got beeps. All good signs?


The next thing I did is test the direct current voltage and I’m getting -22.25 at Pico PS5001 and +21.83 at PS5002, both good signs so far I assume? Just to be sure I decided to check the connections on the convergence board located at CN8013 and here is what I got:

Pin # 1 = -17.7 vdc
Pin # 2 = GND
Pin # 3 = 16.3 vdc
Pin # 4 = -22.2 vdc
Pin # 5 = GND
Pin # 6 = +21.7 vdc
Pin # 7 = GND
Pin # 8 = NC
Pin # 9 = 134.5 vdc


I'm hoping these numbers are encouraging?


Although the convergence is still out, as I was expecting it might be, at least now I know the IC's are getting power. After letting the television run for little over an hour I decided to do a thermal test and put the thermal probe where the IC meets the heatsink. IC8001 came back at a barely warm 100 degrees while IC8002 was a much hotter 121 degrees. Is this indicative of anything? What is an expected somewhat normal operating temp?

I thinking the next step is to replace both convergence IC's? Is there anything else I should test? What are your thoughts and concerns? Thanks again !

-Shawn in Pa
 
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