equivalent for ic switching power supply control

[marcdima]

hi guys,

I need your help

to tell you I am not a professional on electronic

I repair office machines (copier, laser printer ...)

I have a problem with a power supply board for a copier

apparently had a hard blow

many components are burned

I tested and changed I think the majority of burned components (bridge rectifier, filter capacitor, some resistance)

the problem I do not found the original circuit FA3647 I replaced by FA5317
and a transistor 2SA1015 by A733

now I have low output voltage ! 0.7V

i would to know if FA5317 equivalent for FA3647 or not ?

and transistor A733 can replace A1015 ?

for now i can't do anything before I found the replacement for these components

Thank you and sorry for my english

[retiredcaps]

Re: equivalent for ic switching power supply control

the problem I do not found the original circuit FA3647 I replaced by FA5317
and a transistor 2SA1015 by A733

ebay has both of the original parts above.

99 cents for

http://www.ebay.com/itm/250848971061

$5 for IC

http://www.ebay.com/itm/120920840917

[marcdima]

Re: equivalent for ic switching power supply control

thanks for your reply retiredcaps
the problem, not everyone can buy over internet this is not problem of money but this is a policy of my country unfortunately

that why i search for equivalent parts in others board.

If a photo of the board can help I can take a photo and upload it .

the dc voltage in Vcc pin of
power ic FA5317 fluctuate between 9V to 16V

the test voltage in secondary ( diode shotky) = 0.7V

it is a complex supply
it gives 3.35V - 5.1V - 12V and 24V
and 220V to power supply the lamp in fuser unit

here is a picture of the board in ebay
http://www.ebay.com/itm/KONICA-MINOL...-/170915607745

[Khron]

Re: equivalent for ic switching power supply control

FA5317 is *not* a direct replacement for FA3647. If you'll look closely at the block-diagrams (or internal schematics) of each, you'll notice several differences:

1) pin 3, the current sense - it's marked with a "-"on FA3647 and goes to the inverting input of a comparator (internally), and a "+" on the FA5317

2) 3647 seems to only need a resistor for setting the switching frequency, while the 5317 needs a resistor and a capacitor

3) there also seems to be some extra circuitry in the 3647 between the FB pin and the internal oscillator

[budm]

Re: equivalent for ic switching power supply control

Was the FA3647 damaged (burnt, blown up)? Can you take good clear pictures of top and bottom side of the board?

[marcdima]

Re: equivalent for ic switching power supply control

thank you Khron666 for your explanation
I thought even if the internal diagram is different the result is the same, but this is not the case

hi budm the FA3647 blown up


I hope that these pictures in attached files are clear to you because the board is a little big.
the board is fragile the slightest shock can break him just as you can see in
the picture in extremity of board but this is not a big problem,and with all
these components the board can deforms easily .

I changed several components burned into the board , I can tell you these components if you want

thank you guys for your precious time