Power supply build quality pictorial. part 2

[Scenic]

Re: Power supply build quality pictorial. part 2

Scenic:
Haha, thats a good looking supply!, although it could use a bigger heatsink on the regulator.

That's probably the reason why it's labelled as 1amp max., despite the LM317T being able to deliver 1.5amps.

edit: forgot to mention.. mine has 4 diodes hidden behind the heatsink

[Agent24]

Re: Power supply build quality pictorial. part 2

Oh silly, the black round thing is a bridge rectifier

-Ben

Why does it have a diode on the rear side too then?

[mariushm]

Re: Power supply build quality pictorial. part 2

You're right - I opened it up again and it has 4 legs.. so it's the rectifier. I initially counted only 3 legs, that's why I assumed it's a transistor.
Now I'm not so sure about the point of the IN4001 diode on the other side connecting two of the legs of the rectifier...

Yeah... I don't think the transformer is able to do more than 200-300mA....

[goodpsusearch]

Re: Power supply build quality pictorial. part 2

Infact, i could go to the surplus store and get a whole bag of phone chargers for a few bucks, would be interesting to dissect them.

The Best phone charger I have seen was an old nokia charger, it had an Astec power supply, with Lelon and Nichicon caps in it, a nicely sized transistor, a control chip, secondary feedback, and even a mini bridge rectifier on the input!

-Ben

Here it is!

Notice that there are no Nichicons here... Only Lelon and Ltec and some are 85C.

[ben7]

Re: Power supply build quality pictorial. part 2

Here it is!

Notice that there are no Nichicons here... Only Lelon and Ltec and some are 85C.

Heh, is it me or are the primary caps slightly bulged?

-Ben

Edit: the one I took apart must have been a different version, it has a defferent layout, etc.. may be able to post a pic or two tomorrow!

[Th3_uN1Qu3]

Re: Power supply build quality pictorial. part 2

Reminded me of my universal wallwart that i bought when i was 9 or 10 (I'm 24 now).
Except mine does what the label says and i't considerably more beefy than that black blob of plastic and metal that wants to be a PSU in your pics lol

AAA battery for size comparison.
There's a SEC (Samsung) LM317T on that heatsink (capable of 1.5A, so the PSU is underrated by 500mA)

Used to have one just like that. Not sure of its current whereabouts tho.

[goodpsusearch]

Re: Power supply build quality pictorial. part 2

Heh, is it me or are the primary caps slightly bulged?

-Ben

Edit: the one I took apart must have been a different version, it has a defferent layout, etc.. may be able to post a pic or two tomorrow!

No, it's due to the macro and the flash

This is the cheapest nokia charger available. It takes forever to charge big capacity batteries!

[Scenic]

Re: Power supply build quality pictorial. part 2

I had a Nokia ACP-12E (E for europe) made by Astec. Had a break in the cable somewhere.
Caps were Nichicon and Elna.
5.7V 800mA output

The Salcomp (Finland) made ACP-8E had Elna everywhere.
5.3V 500mA output
Most newer ones use LTec and Lelon exclusively.. bye bye quality..

[goodpsusearch]

Re: Power supply build quality pictorial. part 2

Btw the one in the photo had a break in the cable too and that's the reason I opened it.

[lti]

Re: Power supply build quality pictorial. part 2

Here is another wall wart. This is the power supply that came with the Harman Kardon HK-206 speakers I recapped. The filter cap is a Fulltec RHA 2200uF 25V (possibly low ESR) and the diodes are RL201s. Note that there is no thermal cutoff on the transformer and the transformer and circuit board just flop around inside the case when the back cover is removed.

[b700029]

Re: Power supply build quality pictorial. part 2

You're right - I opened it up again and it has 4 legs.. so it's the rectifier. I initially counted only 3 legs, that's why I assumed it's a transistor.
Now I'm not so sure about the point of the IN4001 diode on the other side connecting two of the legs of the rectifier...

Probably because the bridge rectifier has an open diode (or shorted, but they "fixed" that with a short burst of high current ) so it's cheaper to add another diode around it.

Notice the current through the LED changes with the voltage selector switch position

[ben7]

Re: Power supply build quality pictorial. part 2

Probably because the bridge rectifier has an open diode (or shorted, but they "fixed" that with a short burst of high current ) so it's cheaper to add another diode around it.

Notice the current through the LED changes with the voltage selector switch position

Ok, I also think there was a bit of confusion there, I cant see any extra diode on the circut board, just the bridge rectifier, LED, resistor, and capacitor( & switches).

-Ben

[Agent24]

Re: Power supply build quality pictorial. part 2

Ok, I also think there was a bit of confusion there, I cant see any extra diode on the circut board, just the bridge rectifier, LED, resistor, and capacitor( & switches).

-Ben

Check his 2nd photo where it shows the back side of the board.

[ben7]

Re: Power supply build quality pictorial. part 2

Check his 2nd photo where it shows the back side of the board.

Haha, getting myself all confused! Yes, there is a diode there!


But its in a very strange setup :S

-Ben

EDIT:
HAHA WTF! the circuit b700029 drew is correct too, they added an extra diode for some reason.

I am surprised that they will do stuff like this to save money! :O

[Agent24]

Re: Power supply build quality pictorial. part 2

For the quality of the rest of the thing, I'm surprised it's even got a full-wave rectifier!

[ben7]

Re: Power supply build quality pictorial. part 2

For the quality of the rest of the thing, I'm surprised it's even got a full-wave rectifier!

Haha, yeah, some just use one diode

-Ben

[pdavid]

Re: Power supply build quality pictorial. part 2

I had to take a look inside these "replacement" chargers for some Hp laptops... This one is probalby the cheapest out there. I expected much worse.

[japlytic]

Re: Power supply build quality pictorial. part 2

Here it is!

Notice that there are no Nichicons here... Only Lelon and Ltec and some are 85C.

Has Astec gone downhill? They used to have good caps in their power supplies...

[buzzyboy]

Re: Power supply build quality pictorial. part 2

which transistors are on the reverse side pa-3241-02a ?

Did you find out the issue about the transisors? I've got the same question.
Alex

[ben7]

Re: Power supply build quality pictorial. part 2

I found this guys channel on YT, I also love the teardown videos he does!

check out his latest video, he does a teardown of an el-cheapo 'smps' power supply...

-Ben