Need help identifying 8 pin DIP used in Plasma PS PLEASE.

[jango2]

The FA551x parts don't match your pinout discoveries, so I wouldn't
use them. I just cited them for comparison purposes.


It would have helped me a great deal to have known that ...


I don't understand why a 60V audio frequency power transistor would be
used on the primary side of a high frequency switchmode PSU.

I notice that the mains rating of this TV is AC 110-240V (50/60Hz), so
maybe it uses active PFC to boost the voltage on the bulk capacitor to
around 380V. AIUI, this would require a high voltage power
transistor/MOSFET to switch a coil on and off during each mains
half-cycle. The transistor/MOSFET would only need to be rated for low
frequency use. The FA5522N part doesn't seem to have enough pins to
implement APFC, so I would expect that there must be another IC in the
PSU.

Is there any chance you could upload a photo of the PSU to a file
sharing service?

BTW, you can determine the switchmode frequency by monitoring the
anode of any rectifier diode on the secondary winding. You don't need
to risk probing on the primary side.

- Franc Zabkar

"I don't understand why a 60V audio frequency power transistor would
be
used on the primary side of a high frequency switchmode PSU."
Feedback winding on hot side of transformer drives the collector of
2SD2012 via a series diode (pf value cap across), emitter of the
transistor feeds supply to pin 6 of mystery ic (which is vcc of
FA5516/7/8 too) base-emitter resistor 2k2 ohms, emitter to ground
reverse biased diode, another reverse biased diode across C-E. A
common base config transistor acting as a voltage regulator?

"The FA551x parts don't match your pinout discoveries, so I wouldn't
use them. I just cited them for comparison purposes."
They do only if you're looking at the FA5516/7/8 pdf and not the
FA551X datasheet. I see a perfect match. No discrepancies.


"The FA5522N part doesn't seem to have enough pins to implement APFC,
so I would expect that there must be another IC in the PSU."
Bang on! The plot thickens, guess what?, A Fuji FA5502P/M power factor
correction IC mounted on a small glass epoxy pcb labelled PCPF0159
with a Murata logo on it. Only this time they didnt remove the FE logo
on the ic. PFC achieved by that and two 2SK3528 and a huge transformer
shaped inductor.

"BTW, you can determine the switchmode frequency by monitoring the

anode of any rectifier diode on the secondary winding. You don't need
to risk probing on the primary side."

The oscillator totally whacked out of sync, hence the irritating
buzz.

3 images uploaded to
http://s596.photobucket.com/albums/tt46/jango_2/?action=view&current=MPF7437L.jpg

Thanks Franc,

 

[Franc Zabkar]

On May 18, 2:01 pm, Franc Zabkar <[email protected]> wrote:

"I don't understand why a 60V audio frequency power transistor would
be used on the primary side of a high frequency switchmode PSU."

Feedback winding on hot side of transformer drives the collector of
2SD2012 via a series diode (pf value cap across), emitter of the
transistor feeds supply to pin 6 of mystery ic (which is vcc of
FA5516/7/8 too) base-emitter resistor 2k2 ohms, emitter to ground
reverse biased diode, another reverse biased diode across C-E. A
common base config transistor acting as a voltage regulator?

I think so, but there would have to be a zener diode connected to the
base. See your Vestel plasma TV circuit (page 65). I still don't see
why you need a 3A power transistor to supply this IC, though.

BTW, in an earlier post it appeared that you were saying that the
emitter of the 2SD2012 was connected to the current sense input on pin
3. Are you sure pin 3 is not sensing the MOSFET current?

"The FA551x parts don't match your pinout discoveries, so I wouldn't
use them. I just cited them for comparison purposes."
They do only if you're looking at the FA5516/7/8 pdf and not the
FA551X datasheet. I see a perfect match. No discrepancies.

Yes, you're right ... if pin 3 is sensing the current in the MOSFET. I
also thought that pin 1 may not have matched. It appears that the only
difference between the FA5516/7/8 parts is their switching frequency
-- 130kHz/100kHz/60kHz. I wonder what is different about the FA5522?
Frequency? Supply voltage?

In any case, the FA5516/7/8 parts don't seem to be any easier to find.

Searching here ...

http://www.usbid.com/search/AddPartNoLogin_action.cfm

.... finds a US supplier for the FA5522N but the minimum order is $300.
Maybe if you begged ...

Alternatively a broker named Patrick Cheung used to offer parts in
single quantities to members of the sci.electronics community:
http://www.townt.com/towne/

"The FA5522N part doesn't seem to have enough pins to implement APFC,
so I would expect that there must be another IC in the PSU."

Bang on! The plot thickens, guess what?, A Fuji FA5502P/M power factor
correction IC mounted on a small glass epoxy pcb labelled PCPF0159
with a Murata logo on it. Only this time they didnt remove the FE logo
on the ic. PFC achieved by that and two 2SK3528 and a huge transformer
shaped inductor.

Hindsight is a wonderful thing.

This URL could have saved us a lot of grief:
http://translate.google.com/transla....ru/forum/hitachi-42pd9800ta-info-281069.html

The OP blames C102 (101, 2kV) for the "whole tragedy", so it might be
worth checking/replacing.

"BTW, you can determine the switchmode frequency by monitoring the

The oscillator totally whacked out of sync, hence the irritating
buzz.

I thought you still had a good TV to take measurements from.

3 images uploaded to
http://s596.photobucket.com/albums/tt46/jango_2/?action=view&current=MPF7437L.jpg

More photos:
http://monitor.net.ru/forum/files/__________________dsc00003_139.jpg
http://monitor.net.ru/forum/files/__________________dsc00010_147.jpg
http://monitor.net.ru/forum/files/__________________dsc00004_351.jpg

In future may I suggest that you post direct links to your photos.
That way we don't have to suffer the ads and banners.

http://i596.photobucket.com/albums/tt46/jango_2/MPF7437L.jpg
http://i596.photobucket.com/albums/tt46/jango_2/Image002.jpg
http://i596.photobucket.com/albums/tt46/jango_2/Image001.jpg

- Franc Zabkar

 

[Franc Zabkar]

FA5522N-A2-TE1
Would this be the same part?

I don't know.

FWIW, suppliers also list the FA5518N-A2-TE1 part.

- Franc Zabkar

 

[Franc Zabkar]

Nothing showed up on the townt website.

Try emailing him directly:

patrick.cheung at towntarget dot com dot hk

- Franc Zabkar

 

[Franc Zabkar]

FA5522N-A2-TE1
Would this be the same part?
Nothing showed up on the townt website.
Have posted requests everywhere including usbid.
I'm not quitting easy.
I will see this through.

I notice that B&D Enterprises stock some FA55xx parts. Maybe they
could order the FA5522N part for you ???

http://www.bdent.com/search/search.jsp?contains=FA55&category=ALL&submit.search=Search!

FWIW, here is a "Fuji AC-DC IC Series brochure":
http://www.asuntech.cn/upFile/7521153641.pdf

.... and a Fuji SMPS devices brochure:
http://www.indel.com/downloads/fuji_smps_devices.pdf

There are FA5530/5531/5532 and FA5540/5541/5542 parts. They are
described as quasi-resonant ICs.

Here is a spec sheet for the FA5530/31/32 parts:
http://www.datasheetarchive.com/pdf-datasheets/Datasheets-12/DSA-232154.pdf

Here is an app note for the FA5540/41/42:
http://www.fujisemicon-elis.com/en/...2&grp_code=91702&grp_name=For AC/DC&fe_parts=

The FA5532 and FA5542 are spec'ed for 120kHz/130kHz operation.
Therefore I suspect that the FA5522 is also a 120kHz/130kHz part.

FWIW the FA5520 is a 5-pin IC:
http://www.fujielectric.com/company/tech/pdf/r49-3/01.pdf
http://www.fujielectric.com/company/tech/pdf/r49-3/r49-3.pdf

The FA553x parts specify "linearly changed frequency at light load",
whereas the FA554x parts specify "intermittent switching at light
load".

This is Fuji's datasheet site:
http://www.fujisemicon-elis.com/en/

FWIW the FA5542 part is listed as still available. Maybe it would be
worth a gamble ???

The FA557x parts may be worth a look, too:
http://www.fujisemicon-elis.com/en/...1&grp_code=91702&grp_name=For AC/DC&fe_parts=

You might also like to search for ...

FA5502 filetypedf

Maybe you will find a service manual for a device that uses this APFC
IC in conjunction with another Fuji part.

I'm no expert, but it seems to me that you need to find out whether
the FA5522 is "current mode" or "quasi-resonant". The difference
appears to be that pin 1 is either CS (soft start/latch-mode stop) or
ZCD (zero current detect). Maybe you should do some tracing around
that pin and consult the application examples.

- Franc Zabkar