Tagan TG480-U01 480W ATX PSU

[JEWilson]

Re: Tagan TG480-U01 480W ATX PSU

Y - I know how the +5VSB typically works in these PSU.
The TL431 is only a voltage reference shunt regulator.

This PSU appears to have two PWM ICs in the main PSU.
These are Texas TL3842P and a Texas TL494CN
The first is the main PWM controller you requested.
This PSU also has a negative rail regulator in the secondary.
Nothing particularly unusual.

I have attached the drafts of the A-PFC cct.
I expect you might find these a little confusing, then again
you may not.

I will get back to you with findings

Thx

[JEWilson]

Re: Tagan TG480-U01 480W ATX PSU

I just got round to testing the voltage across the primary
caps. Reads 178.0V with A-PFC cct. in place.

So... it may be there exists a problem with A-PFC
Next steps.

Bypass the A-PFC with a bridge rectifier to same rating
and measure voltages across the primary smoothing caps again.

Anything else?

[i4004]

Re: Tagan TG480-U01 480W ATX PSU

>Anything else?

why such a big delay?
thread was started mid december...

oh yeah, anytime when working with mains check for possible short circuit condition prior to plugging it in...(though you probably knew that already)

>So... it may be there exists a problem with A-PFC

not "may be" but it's now obvious apfc is malfunctioning...

[JEWilson]

Re: Tagan TG480-U01 480W ATX PSU

I have been busy with work as well as seeking new work

Y - As the PFC comparator was replaced, as a start,
I'll start investigating the the discretes around that cct.

Will report back in due course

Thx.

[RogerL]

Re: Tagan TG480-U01 480W ATX PSU

I do also have a Tagan TG480-U01

Has worked perfectly for a very long time on my main/server computer. More or less always on.

Today when coming home from work it is dead.
Nothing... especially no 5vsb...

Time to buy a new psu... did you ever get it to work again?

[stj]

Re: Tagan TG480-U01 480W ATX PSU

open it an take some foto's of the bad caps

[Majestyk]

Re: Tagan TG480-U01 480W ATX PSU

I´m repairing a Tagan 480W PSU at the moment.
After replacing all the bloated "Asia`X" = Fuhiyyu capacitors the PSU still wouldn´t start. No secondary voltages, no standby voltage.
I found the PWM-Controller (a TL3842P) to have a resistance of about 100 Ohms between Vcc and Gnd.
I have ordered a replacement and will report the results.

[Majestyk]

Re: Tagan TG480-U01 480W ATX PSU

The PWM Controller (TL3842P) was indeed the culprit here.
After replacing it, the PSU works flawlessly again.
Here is the finished product:

[goodpsusearch]

Re: Tagan TG480-U01 480W ATX PSU

Congrats!

[Pentium4]

Re: Tagan TG480-U01 480W ATX PSU

That's amazing, nice going! I'm glad you fixed that PSU. Gotta love those old school Topower units. They're good performers. It'll last forever now

[Majestyk]

Re: Tagan TG480-U01 480W ATX PSU

Yes, it´s a very nice PSU now with very little noise and enough power for most common systems. It has got a railsplit switch for +12V also.

With all the high quality capacitors it should now be ready for a considerably long lifetime.

I´m quite sure the TL3842P PWM-controller was the real reason for this PSU to stop working. The secondary filter caps (ASIA-X) all had a capacity of several hundred uF left so they probably would have led to instabilities but the PSU suddenly stopped worrking compltely - because the PWM-controller died.
I think exactly this might have been the case with the other Tagans in this thread.

I have been repairing defective PSUs that I replaced in the computers of my customers for many years now (I only fit in brand new PSUs in my customers´ machines for warranty reasons) and I use them in my own systems for a "second life" then. None of them has ever failed again.

[Behemot]

Re: Tagan TG480-U01 480W ATX PSU

Clean that chloroprene glue you have there otherwise it's going to degrade completely and get conductive.

What caps did you use? I see some fat panasonic on the SB rail but some caps which make me unsure of their quality…

[Majestyk]

Re: Tagan TG480-U01 480W ATX PSU

The glue has been generally removed in areas, where there´s contact to higher voltages. I left some traces on coils and tranformers to avoid mechanical or chemical demage when removing them. The bleeder resistors of the primary filter caps have some traces left on their outsides also but the pcb is clean.

But, you´re right - there´s still glue on the PFC board. I will take care of this soon. (see picture)


As for the capacitors, I used Nichicon GG on the primary side (not enough space for GX), Rubycon ZLJ (the smaller values), Panasonic FR and Nichicon HW for seconadry filtering.

Hope there´s nothing wrong with that.

[Behemot]

Re: Tagan TG480-U01 480W ATX PSU

Don't know HW, that is some new series?

FR only has 3300/16 in D12,5x30 mm.

[Majestyk]

Re: Tagan TG480-U01 480W ATX PSU

Yes, Nichicon HW is a quite new series (End 2012) 10.000h, low impedance, high ripple, Long life:

http://www.nichicon.co.jp/english/pr...ws/new130.html



Here I used 2 x 3300µ 16V and 3 x 2200µ 10V


The Panasonic are "FR" indeed 2 x 4700µ 10V. (I just looked in my stock.) 12,5 x 30
They are made in Malaysia by the way.

[Behemot]

Re: Tagan TG480-U01 480W ATX PSU

This seems like there is no 16V rail when you only used 10V caps Anyway both FR and HW are very low ESR, almost like old ultra-low ESR series, I would use that in PSU only with extreme caution.

[Majestyk]

Re: Tagan TG480-U01 480W ATX PSU

Sorry, typo! -> 2 x 3300µ 16V

[Behemot]

Re: Tagan TG480-U01 480W ATX PSU

I see Nex time I can supply you with those in D10, probably cheaper than you buy them now and within few days (its not far from Prague).

[Majestyk]

Re: Tagan TG480-U01 480W ATX PSU

I Keep that in mind! Here there was enough space for 12.5 but often there is not.

If you are near Prague you can almost throw them over to me

I know, some people had problems with very low ESR caps in PSUs - I haven´t so far.

[Majestyk]

Re: Tagan TG480-U01 480W ATX PSU

By the way: Nichicon are recommending their "HW-Series" specially for switching power supplies with high temperatures / long life / high ripple.