These tv sets are at work in a corner so i dont have the model numbers
but i`m sure some of you would have seen these by now .
Last years model . The cabinets are totaly plastic , the set is not very
tall .
I have 9 of these sets saved and all have severe convergence distortion
on the picture .
The convergence module on these hangs on the metal support that holds
the 3 tubes .
the module has 2 large STK chips on them that i suspect is the problem .

Is there a reason so many , perhaps ALL of these sets have this problem
? is there a hidden KNOWN problem on these making it a waste of time
ordering that many STK chips ?
The sets belong to a salvage store where i work on the electronics . I
am not an expert but can replace such parts . They dont want to spend
hundreds getting these fixed so a service shop is out .

Thanks.

I went looking on the net for these pieces of crap and cant find any .
They may be 2 or 3 years old ?? They are still coming in as store
returns so ??

First of all, use lateral thinking, later it will lead you to
omnidirectional thinking. Change the chips on ONE board and run it
through all the sets, one at a time. Make sure to check everything that
even looks fusible, and of course see it work in at least one set. Once
it works transfer the board from set to set. All the ones it works in,
order chips for them, and get one extra set for a board you keep, to
fix the rest.

You don't even have to screw the board in, just plug them in. The ones
that don't work, go farther, but at least (hopefully) get the bulk of
it out of there. ( or fixed, whatever ).

You need to get to know what the picture looks like without convergence
correction, this way you can make (in the future) an educated guess as
to what's wrong.

Once you got X amount of them fixed, go on to the rest.

Yes, I'm a pro, but I still work for an old horse trader. When you lack
detailed service info, multiple identical units are the best thing to
have.

JURB

Also, Inspect the sets throughly for any signs for coolant leakage from any
one of the three crts. This is a very common problem in Samsung / Akai RPTV
CRT sets. Any incidence of finding fluid will preclude how you will attempt
servicing them.
wrote in message
ups.com...
First of all, use lateral thinking, later it will lead you to
omnidirectional thinking. Change the chips on ONE board and run it
through all the sets, one at a time. Make sure to check everything that
even looks fusible, and of course see it work in at least one set. Once
it works transfer the board from set to set. All the ones it works in,
order chips for them, and get one extra set for a board you keep, to
fix the rest.

You don't even have to screw the board in, just plug them in. The ones
that don't work, go farther, but at least (hopefully) get the bulk of
it out of there. ( or fixed, whatever ).

You need to get to know what the picture looks like without convergence
correction, this way you can make (in the future) an educated guess as
to what's wrong.

Once you got X amount of them fixed, go on to the rest.

Yes, I'm a pro, but I still work for an old horse trader. When you lack
detailed service info, multiple identical units are the best thing to
have.

JURB

Thanks guys . I did look for coolant leaks and none had it but i have
seen it in the past and junked those sets for parts .

The models are Samsung HCM 4215W and AKAI PT4298HDX/SMS
Both models have P55A chassis .

I like the idea of buying 2 or 4 chips and try the circuit in all . I
did save a couple by using chips from leaker sets .
I was concerned a bigger problem caused these chips to fail in so many
sets .

Hey Ken, I have the same problem with my tv (Samsung HCM4215W) and was
wondering if you were able to fix yours. My local repairman said the
estimate was $300 for a convergence module, but from reading online, it
seems like I just need either two new IC's, or a new convergence board
with the two IC's. Any help?

On 21 Oct 2005 10:49:18 -0700, wrote:

Hey Ken, I have the same problem with my tv (Samsung HCM4215W) and was
wondering if you were able to fix yours. My local repairman said the
estimate was $300 for a convergence module, but from reading online, it
seems like I just need either two new IC's, or a new convergence board
with the two IC's. Any help?


Ask the shop that tech works for, is this shop he works for samsung
servicer authorized? This is only way shops can get service manuals
and schematics for Samsung stuff.

300 estimate is about right. I have done many of these.

Cheers, Wizard

I found the chips on line for 15$ each . We dont want to spend much on
these so 4 chips were ordered and on the way .
I will replace them on one board and make sure all those fuse resistors
are good then try it out .
Any sets that it fixes will get more chips ordered .

I know all about buying cheap parts but this is orders from headquarers
If it dont work the sets go away broken .

"Jason D." wrote in message
...
On 21 Oct 2005 10:49:18 -0700, wrote:

Hey Ken, I have the same problem with my tv (Samsung HCM4215W) and was
wondering if you were able to fix yours. My local repairman said the
estimate was $300 for a convergence module, but from reading online, it
seems like I just need either two new IC's, or a new convergence board
with the two IC's. Any help?


Ask the shop that tech works for, is this shop he works for samsung
servicer authorized? This is only way shops can get service manuals
and schematics for Samsung stuff.

300 estimate is about right. I have done many of these.

Cheers, Wizard

Rates will vary, but $300 is not out of line in many markets. We usually
repair the boards rather than replacing them. Like many repairs, these can
be a can of worms for someone not familiar with doing these repairs.

You can buy the manuals from distributors or download them from several
sites where shops share manuals, or get them from another shop that is
authorized, just like the way you can get tips from other servicers. We are
not Samsung authorized and this is one manual that I got from Tritronics for
a little over $10.

Leonard

Hey thanks Jason

So what exactly is the convergence module? From looking at the tv set,
I can see the two IC's, connected to the convergence AMP board, that
sits in a metal alloy heat sink, that is screwed/hangs right behind the
three crt's. Even looking around via google, I can't seem to find any
replacement convergence module's, or even any pics of it. What does it
look like? I did find a thing infront of the middle (green) crt board
with some numbers on it (sorry!) with a label like VM008 something.

Also from reading around, it seems like the convergence module costs
$300, so are they even charging me for labor? How much would a
convergence module cost on its own?

So, from what the serviceman told me (a new convergence module) would
getting a new convergence amp board (AA95-2002A is the one being
recommended), with two new convergence IC's (STK392-040) fix the
convergence problem I have?

On 21 Oct 2005 21:20:08 -0700, wrote:

Hey thanks Jason

So what exactly is the convergence module? From looking at the tv set,
I can see the two IC's, connected to the convergence AMP board, that
sits in a metal alloy heat sink, that is screwed/hangs right behind the
three crt's. Even looking around via google, I can't seem to find any
replacement convergence module's, or even any pics of it. What does it
look like? I did find a thing infront of the middle (green) crt board
with some numbers on it (sorry!) with a label like VM008 something.

Also from reading around, it seems like the convergence module costs
$300, so are they even charging me for labor? How much would a
convergence module cost on its own?

I'm not sure where you got the prices, but we can't tell you the
actual prices, just only the retail prices that customer sees along
with labor rate. We have to earn our keep to put our meal on the
table and have roof over our heads and pay for shop's overheads.

Also good shops had to be careful of fake components including ICs.
They do exist out there and I have seen this happen.

So, from what the serviceman told me (a new convergence module) would
getting a new convergence amp board (AA95-2002A is the one being
recommended), with two new convergence IC's (STK392-040) fix the
convergence problem I have?


The tech was doing safe way out by replacing both ICs to cut down on
call backs and make you happy. Many times we get away with just one
just that we know WHICH IC is the dud by looking at the images on tv.
After that, touch up adjustment to convergence and memorize it so
autofocus or autoconvergence will work correctly. This is reason for
schematics and service manual. It is about 50 pages long and also
that cost pretty penny.

To others doing this same on removeable Samsung convergance amp module
that mounted to the CRT steel frame, I put dollop of thermal grease
around that screw hole (goes on between this heatsink and the steel)
to improve the heat transfer ditto some thermal grease to the IC even
module already have thermal pad.

Plus we must repair to component level since cost of a complete module
assembly is too expensive even for warranty job even let alone to
customer.

Cheers, Wizard

On Fri, 21 Oct 2005 21:35:20 -0600, (Ken G.) wrote:

I found the chips on line for 15$ each . We dont want to spend much on
these so 4 chips were ordered and on the way .
I will replace them on one board and make sure all those fuse resistors
are good then try it out .
Any sets that it fixes will get more chips ordered .

I know all about buying cheap parts but this is orders from headquarers
If it dont work the sets go away broken .

Ken G.

This is not good idea to appoach this. Make sure that ICs is real
thing not fakes. The ICs on these convergence designs run very hot
and ESPECIALLY that samsung is using these ICs in place of convergence
rings. Oh boy. Many samsung models didn't come with these rings on
the yokes. By the way, the convergence windings is about 20 turns on
each one of four sectors on the ferrite ring. Very, very low ohms for
the poor IC to drive them.

Cheers, Wizard

"Jason D." wrote in message
...
On Fri, 21 Oct 2005 21:35:20 -0600, (Ken G.) wrote:

I found the chips on line for 15$ each . We dont want to spend much on
these so 4 chips were ordered and on the way .
I will replace them on one board and make sure all those fuse resistors
are good then try it out .
Any sets that it fixes will get more chips ordered .

I know all about buying cheap parts but this is orders from headquarers
If it dont work the sets go away broken .

Ken G.

This is not good idea to appoach this. Make sure that ICs is real
thing not fakes. The ICs on these convergence designs run very hot
and ESPECIALLY that samsung is using these ICs in place of convergence
rings. Oh boy. Many samsung models didn't come with these rings on
the yokes. By the way, the convergence windings is about 20 turns on
each one of four sectors on the ferrite ring. Very, very low ohms for
the poor IC to drive them.

Cheers, Wizard

What do you mean by "ICs in place of convergence rings?"

The inductance on the Samsung convergence yokes are not much different than
other brands. They tend to run a little hotter than some that use the same
chips, but virtually every manufacturer that uses these outputs has similar
reliability. Some use more or less resistive loading on the outputs, but
they all run pretty hot.

Leonard

On Sat, 22 Oct 2005 08:34:55 -0400, "Leonard Caillouet"
wrote:

and ESPECIALLY that samsung is using these ICs in place of convergence
rings. Oh boy. Many samsung models didn't come with these rings on
the yokes. By the way, the convergence windings is about 20 turns on
each one of four sectors on the ferrite ring. Very, very low ohms for
the poor IC to drive them.

Cheers, Wizard

What do you mean by "ICs in place of convergence rings?"

Well, with active convergence disabled, the convergence rings that you
get green CRT centered then move other two CRTs convergenced to that
green in the center (usually!) or other models had red and blue set
certain distrance from green and finish rest of way with convergence.

Now, many Samsung units did not use the rings. Relying on ICs to push
all the beams together is very hard job for both STK ICs, hence runs
much harder and very hot. That's the reason for fairly high failure
rates.

Think of a thick wall tube about 1/2" length, that's the ferrite core,
four windings in one layer in four sectors, each sector 20 turns
around the core (toroidal). The assembly goes through the CRT's neck.
Others like RCA uses 4 poles with more turns around each pole and
easier to pull beam around and less stress on the convergence amps.
Oh yeah, Samsung sometimes used sloppy solder joints (just magnet wire
and wirings twisted together & soldered. I had one come apart once.

I have yet to see convergence of this Thomson (RCA) discrete
convergence amp design fail YET except for rare thermal defective,
only happened once and was fixed by co-worker 2 years ago.

Cheers, Wizard

The inductance on the Samsung convergence yokes are not much different than
other brands. They tend to run a little hotter than some that use the same
chips, but virtually every manufacturer that uses these outputs has similar
reliability. Some use more or less resistive loading on the outputs, but
they all run pretty hot.

Leonard

"Jason D." wrote in message
...
On Sat, 22 Oct 2005 08:34:55 -0400, "Leonard Caillouet"
wrote:

and ESPECIALLY that samsung is using these ICs in place of convergence
rings. Oh boy. Many samsung models didn't come with these rings on
the yokes. By the way, the convergence windings is about 20 turns on
each one of four sectors on the ferrite ring. Very, very low ohms for
the poor IC to drive them.

Cheers, Wizard

What do you mean by "ICs in place of convergence rings?"

Well, with active convergence disabled, the convergence rings that you
get green CRT centered then move other two CRTs convergenced to that
green in the center (usually!) or other models had red and blue set
certain distrance from green and finish rest of way with convergence.

Now, many Samsung units did not use the rings. Relying on ICs to push
all the beams together is very hard job for both STK ICs, hence runs
much harder and very hot. That's the reason for fairly high failure
rates.

Think of a thick wall tube about 1/2" length, that's the ferrite core,
four windings in one layer in four sectors, each sector 20 turns
around the core (toroidal). The assembly goes through the CRT's neck.
Others like RCA uses 4 poles with more turns around each pole and
easier to pull beam around and less stress on the convergence amps.
Oh yeah, Samsung sometimes used sloppy solder joints (just magnet wire
and wirings twisted together & soldered. I had one come apart once.

I have yet to see convergence of this Thomson (RCA) discrete
convergence amp design fail YET except for rare thermal defective,
only happened once and was fixed by co-worker 2 years ago.

Cheers, Wizard

The inductance on the Samsung convergence yokes are not much different
than
other brands. They tend to run a little hotter than some that use the
same
chips, but virtually every manufacturer that uses these outputs has
similar
reliability. Some use more or less resistive loading on the outputs, but
they all run pretty hot.

Leonard

I have never noticed that they did not have centering magnets. Every one
that I have done was pretty close after repairing the output module. In
other words if the variance in the yokes is very large, they have to correct
the excessive offset with dc bias? Not a good design, IMO. This would make
them run hot. The last one that I measured ran at about 60 degrees C,IIRC,
pretty typical for the STK392-040. That is with the back off. They likely
run hotter with the back on, due to the fact that they are mounted so high
in the set compared to other brands. Also a dumb design, IMO. Never saw
one where excessive bias was the case, as one thing we always check is for
dc ofset of more than a couple hundred millivolts on the outputs ( a habit
developed in the old Novabeam days...). But then, I have only done a few of
this set and they were pretty routine, except that tweaking the convergence
is a PITA and the various adjustments seem to interact a lot.

Leonard

Leonard,

Yes, run HOT!

Using bias to position all CRTs instead of rings.

Usually you get good results with just a IC, except many I had to
replace burned resistors and fuse then have to slightly adjust
convergence and memorize it with autofocus while still in service
convergence mode.

When I have chance I'll take a pic of samsung convergence coil
assembly.

Cheers, Wizard

"Jason D." wrote in message
...
Leonard,

Yes, run HOT!

Using bias to position all CRTs instead of rings.

Usually you get good results with just a IC, except many I had to
replace burned resistors and fuse then have to slightly adjust
convergence and memorize it with autofocus while still in service
convergence mode.

When I have chance I'll take a pic of samsung convergence coil
assembly.

Cheers, Wizard

Every one that I have done has needed resistors and fuse also.

Samsung's price on the output ICs is ridiculous, too. Are they trying to be
Sony with respect to parts prices, or what? At least Sony is starting to do
something about it.

Leonard

Thanks, again, to everyone that replied

So, from this website, Vancebaldwin.com, what would be the best part
for me to get :

AA95-02002A ($65.68)

Or :

AA95-02002A ($178)

Or :

BP94-00383A ($70)

My question is, do these boards come with the two new IC's already
soldering onto them? Will they be good IC's, not cheap ones? Also,
whats with the different prices? The BP94 model is listed as a
"substitute" model, but it's also listed for the HCM4216 model, not the
4215. Would it run ok on my television? Just sorta confused...

Again, thanks for the help you guys
Eric