Comments on: 400 Watt PC Power Supply Repaired

By: Lad

Lad — Thu, 18 Aug 2016 20:27:17 +0000

Hi ALbert,
Thank you for your great articles about reparing. As I could see you use more transistor testers.Can you please recommend one(best) tester for me?
Thank you

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By: majid

majid — Sun, 29 Nov 2015 19:34:53 +0000

Thank you

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By: Raju varghese

Raju varghese — Thu, 19 Nov 2015 07:59:54 +0000

Hi Albert, good and valuable information thank you for sharing

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By: Albert van Bemmelen

Albert van Bemmelen — Sun, 15 Nov 2015 10:37:51 +0000

More on the Basics on PFC (Power Factor Reduction), which can be
defined as the reduction of the harmonic content to minimize the
input current distortion, can be read on in this PDF:
https://www.fairchildsemi.com/application-notes/AN/AN-42047.pdf
This also improves the Power Factor to be equal to 1
(when cos phi 0 degrees = 1). So Input Current and Voltage are in
Phase. After all Power (Watt) = Voltage x Current x cos phi.

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By: Albert van Bemmelen

Albert van Bemmelen — Sat, 14 Nov 2015 14:23:25 +0000

This link also gives very interesting information about the new
Low Start-Up current PFC/PWM Controllers in some new SMPSs. Like
the in above Post mentioned AN4800 PFC/PWM controller which in
fact is a FAN4800 chip. See this Fairchild link:
http://www.clubedohardware.com.br/datasheets/FAN4800.pdf
This technique used makes it a bit harder to understand what is
going on in any defective supply that uses such a controller.
Which means that we probably also need to examine the datasheet
of the AN4800 or any other PFC/PWM controller to be able to fix
those defect Power Supplies that use these parts.

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By: Jestine Yong

Jestine Yong — Sat, 14 Nov 2015 14:04:10 +0000

In reply to Robert Calk.

Hi Robert,

This post Reply button seems to have problem and Albert
have asked me to post this:

And that the Aoyue Desolderstations are at least 33% cheaper.
Such as the Aoyue 474A++ that is only $145
(+ 45.44 Shipping & 38.58 Importing). Or the Aoyue 701A++
that costs $185 (+ 47.18 Shipping & $ 46.93 Importing).

Only some sellers like from Israel sell Hakko's
cheap at $140 for a complete Hakko 707. (excl. Shipping and Import).

Albert

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By: Robert Calk

Robert Calk — Thu, 12 Nov 2015 21:03:20 +0000

In reply to Albert van Bemmelen.

I apologize Albert, I guess they changed the number.
Last year when I read about it, they said the European
model like the US model 808 was going to be the 888.
I guess they changed their mind for some reason.
Anyway, here is their site with some de-soldering guns:
http://www.hakko.com/english/products/desoldering/desoldering_tool/

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By: reza

reza — Thu, 12 Nov 2015 19:13:00 +0000

hi Albert van Bemmelen
thank u .

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By: Albert van Bemmelen

Albert van Bemmelen — Thu, 12 Nov 2015 10:42:05 +0000

In reply to Ulises Aguilar Pazzani.

Thank you Mr.Ulises. Repairing SMPS, or ATX PC
Power Supplies is fun. But I still have a couple
of them that still are defect and more
costly to repair. Because they have special
PFC/PWM intergrated circuits
(for instance the SOP-16: AN 4800) plus a special primary
PWM switching circuit in a 8 dip IC (for instance a TNY 277PN).
And the latter has probably a defect Mosfet integrated in the
8 Dip IC why the Power Supply now doesn't work. And replacing
both will be more difficult if they aren't available.
By-the-way: Intel introduced this FormFactor in the year 1995.
See this PDF file:
http://www.formfactors.org/developer%5Cspecs%5CPSU_DG_1_0.pdf
or download read this link that explains some of the
theory behind it:
http://www.tomshardware.com/reviews/power-supply-specifications
-atx-reference,3061-3.html

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By: Albert van Bemmelen

Albert van Bemmelen — Thu, 12 Nov 2015 10:21:35 +0000

In reply to Humberto.

Hi Humberto. Where do you buy these MJE13007 Power Transistors
while living in Cuba? Also on Ebay? Or can you directly
order them from the United States? Because I noticed
that prices had gone up while buying them on Ebay compared
to about 8 months earlier.

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