Hp lj 5n.

[yafch]

Hello friends.
I am so disturbed since this morning. when i went to my hobby table i switched on the power of my HP laserjet 5N printer. i have been using it for some time to print pcb designs. As soon as i switched on the power i heard a poof inside the printer and so it did not come on.
i opened the printer and found dead power supply unit.
Long story short i have detected the problem in the power supply unit. SMPS IC is gone along with few other resistors burnt badly and a couple of dead rectifiers. THE SMPS ic is FA5311. Still can't find it so looking for replacement part.Can any one help me?. Further i need schematic for the power supply unit.


Thank you very much.

 

[3v0]

Google has several hits for it.

The datasheet can be downloaded at


Finding the part itself may be a problem.
None of the places I normally look at have it.

Buy Electronics may have it but they look like one of the places they buys and sells excess parts and inventory. The only time I worked with one of these places they had a $50 min order.
**broken link removed**

Perhaps you can get a similar printer with a working supply from ebay.

EDIT: You may already know this but it is possible that the regulator killed other IC as it died. Especially if there are burned resistors on the output side. Now that you have a datasheet for the regulator you can figure that out.

 

[HarveyH42]

I've got the HP Laserjet 1020, paid $89, new directly from HP. Toner from HP costs $69... Don't know your model, but HP usually has some model on sale for around $100 (or less). Of course it's always fun to fix things yourself for a few dollars, but I'm not sure this is going to be worth the effort. Have you found out why the chip failed in the first place? Once you find the chip, and replace all the burnt parts, how sure are you that it won't fail again? Probably worth getting an extra chip or two, just in case, since it's not a common part, and should effect shipping costs.

I've had mine for a few years, only two issues. The first was the recycled toner cartridge, worked fine on paper, but useless for PCBs. Recently had a Windows Vista issue with print drivers, which was kind of strange thing to suddenly just pop up. I had the automatic updates shut down, since the computer was running stable. Was just dumb luck, that I thought to check for updates.

 

[yafch]

Thank you guys for your replies. I got some help from a professional serviceman and we figured out the resistor values. He suggested nearest match for the ic to be KA5311 and KA7552 but some tweaking with the circuit may be needed.
I am going to look for the replacement parts tomorrow and see what happens.
The apparent reason for the failing of IC , as far as i figured is few loosed solder joints may be due to aging.
If The power supply unit is going not to work after repairs or failed again then my first choice will be to go to some surplus supply shops or even junkyard. Many time before i had luck to find there what i needed.

And HarveryH42 i never used my new computer and printer for my electronics hobby related tasks.Actually i keep two computers and two printers.The one set that i use for electronics hobby is an old Compaq desktop computer running windows XP. The other one is Dell 1545 laptop running windows vista. you know electronics hobbyists are always at risk of blowing up their computers ports and interfaces that could be serious problem.
So it would be a really good idea to use an old computer for hobby tasks.
Thanks a lot.

 

[hdc090360]

You might want to try Ebay. An entire 5n goes for about $30 australian.

 

[yafch]

Hi again. Luckily i found the ic today. Did not soldered it to pcb but used a 8 pin base for easy removal. Power Mosfet was also damaged, and replaced it with same number i had in my junk box and was salvaged from another computer power supply.
A diode at pin 5 of the ic along with a resistor in parallel is detected to shorted.
I did not power up the unit yet for preventing any further damage to the unit because i can't recognize the diode.
I am sure it is not a zener diode. may be a fast switching or recovery diode. The problem is it has no marking on it,instead it has a single line for polarity on it and the line is blue. the diode has glass body just like an 1N4148 but is smaller in length. It is a Japanese diode i am pretty sure, all other parts are Japanese in origin.The supply unit is also made in japan by "SANKEN".
Many time before i had issues in identifying such single color coded rectifiers in Japanese electronics equipment.
Can any one help me with this issue?

Thanks a lot.