J
jango2
Guest
On May 18, 2:01 pm, Franc Zabkar <fzab...@iinternode.on.net> wrote:
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

3 images uploaded to
http://s596.photobucket.com/albums/tt46/jango_2/?action=view&current=MPF7437L.jpg
Thanks Franc,
"I don't understand why a 60V audio frequency power transistor wouldOn Mon, 18 May 2009 01:19:48 -0700 (PDT), jango2
crow_slap...@yahoo.co.uk> put finger to keyboard and composed:
On May 18, 1:27 am, Franc Zabkar <fzab...@iinternode.on.net> wrote:
On Mon, 18 May 2009 06:09:01 +1000, Franc Zabkar
fzab...@iinternode.on.net> put finger to keyboard and composed:
I feel certain that your mystery part is a Fuji FA5522N, whatever it
is.
Here are more documents that may help. Page 9 of the "part number
explanation" associates the "55" with an AC/DC converter controller.
http://www.fujisemiconductor.com/old_pdf/app_notes/FA5516_5517_5518_A.......
There is an email address at this URL:http://www.fujisemiconductor.com/
I can't find a datasheet for FA5522. I'm not at work yet, need to
relook at FA5516/7/8 as the closest match so far. Pin 7 is NC too.
The FA551x parts don't match your pinout discoveries, so I wouldn't
use them. I just cited them for comparison purposes.
I checked below the mystery IC and it has "Japan" embossed on it
It would have helped me a great deal to have known that ...
So that would mean Fuji Japan made this for Murata and even printed
their logo on it, withheld datasheet as it's OE.
Hmm will revert back by evening and will even check for local
availability of FA5516/7/8. I have to probe into the 2sd2012 mystery
too,
Trace that section further. I will report discrepancies then.
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
--
Please remove one 'i' from my address when replying by email.
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
buzz.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
3 images uploaded to
http://s596.photobucket.com/albums/tt46/jango_2/?action=view&current=MPF7437L.jpg
Thanks Franc,