TAGAN TG530-U15 fuse blow possible pfc cause

[sententia]

Hello everyone,

I have this PSU which has been recapped few years ago and has endless running hours on its solders since it was bought.

Something shorted one day and fuse was blown so it has been on the shelve for a year now. Just for exercise, cause i assumed it would be something simple, i am trying to repair it now. First of all do you think it has some juice left?

And now to the main problem.

There is a small pcb, which i think is the APFC, that measures between the +- of
the rectifier 0 resistance. I found that a big resistor (it looks like one) with strange color code that seems to be the problem (measures 0 resistance). With that removed there doesn't seem to be any short in the circuit.

Any ideas?

Your help is greatly appreciated.

P.S. There seems to be some minor problems at the output rails but i doubt that is the cause of the blow fuse. Also the NTC thermistor has a small part missing but seem to work.

[Kiriakos GR]

Re: TAGAN TG530-U15 fuse blow possible pfc cause

Read the color code from left to right.

[sententia]

Re: TAGAN TG530-U15 fuse blow possible pfc cause

Thanks for the quick reply.

If i read the color from left to right it gives me 0.05 ohm (although i can't find a 5 band resistor with all color codes of this one) which, if that is correct, will not be the short problem as this resistor is almost of 0 resistance....

P.S. Eyxaristw!

[budm]

Re: TAGAN TG530-U15 fuse blow possible pfc cause

One thing for sure, you must remove all those brown glue, they are corrosive and conductive. That resistor is less than one Ohm (Brown, Green, silver etc). How is that resistor connected in the circuit, it can be the MOSFET Source resistor or fusible resistor.

[sententia]

Re: TAGAN TG530-U15 fuse blow possible pfc cause

The resistor really looks like black, green, silver etc. Indeed one end of the resistor is connected to MOSFET source and + of rectifier and the other seem to go to - of rectifier. In previous post there is the bottom of the pcb if that is of any help.

[budm]

Re: TAGAN TG530-U15 fuse blow possible pfc cause

As long as the resistor is not open, it will be OK. So the MOSFET's do not tested out as shorted?

[sententia]

Re: TAGAN TG530-U15 fuse blow possible pfc cause

Sorry for the novice question but can they be tested on board?
Gate to drain gives me 170 ohm resistance and drain to source almost 0.
If i read the datasheet correctly do they need 30v to trigger the gate and test their functionality (toshiba k2837)?
Thanks a lot!

[budm]

Re: TAGAN TG530-U15 fuse blow possible pfc cause

Most common failure mode for the MOSFET is the shorts between Source and Drain, if it show 0 Ohm on S & D when tested on board, then you should verify again with it off the board.
This is the typical PFC circuit:
https://cdn.badcaps-static.com/pdfs/...0c7ba8e0b1.pdf
You should check the all the active components, The PFC IC can be damaged also when the MOSFET failed (Gate to Drain shorted).

[Kiriakos GR]

Re: TAGAN TG530-U15 fuse blow possible pfc cause

Just of curiosity I need to ask, do you own an Oscilloscope ?

[sententia]

Re: TAGAN TG530-U15 fuse blow possible pfc cause

Yep! One of the two MOSFETs is shorted...

Do you think that this PSU is worth repairing as:
a) For some reason the part seem to be quite expensive in Europe (Only from China you can get it for 2 bucks)
b) It has been running for some years 24/7 and only output capacitors have been changed
c) There seem to be another problem (see image) which i think was not caused at the time when the short happened

I have seen the exact same model mentioned in another thread does not have the PFC and where the cables are connected to the main PCB there is the rectifier.

http://www.jonnyguru.com/modules.php...e=print&reid=8

So should i try to fix it and make something like a bench power supply or should i start harvesting?

Your help is greatly appreciated and also i learned something today!

Best regards.

[sententia]

Re: TAGAN TG530-U15 fuse blow possible pfc cause

Just of curiosity I need to ask, do you own an Oscilloscope ?

No unfortunately!

[Kiriakos GR]

Re: TAGAN TG530-U15 fuse blow possible pfc cause

Those PSU were retailing at 150 Euro, it sounds wiser to offer 40 Euro in one expert homeboy of yours so to repair it for you.
Harvesting will not help much, you do not own one LCR so to test if those capacitors are reusable keepers or plain garbage.

[Nikochan]

Re: TAGAN TG530-U15 fuse blow possible pfc cause

I have two of those one 530W (stopped using it due to some kind of coil whine) same as yours and a 480W which I bought as a backup PSU. I'm going to replace a few leaked caps in both of these with Panasonic FRs as soon as I bought a goddamn iron.

I don't know if this would help you but your burnt resistor near the heat sink reads as green-grey-brown-gold (580 ohm?) in my 480W.

As for whether or not these are worth repairing, well, these were probably one of the earliest modular PSUs and their feature list sounds impressive, they came with good quality cables and accessories, but I really think that their design isn't very good. They have bad quality caps, their fan runs at a slow speed in order to achieve quietness and they get really hot as a result while working. Perhaps they're worth recapping, but nothing more.

[sententia]

Re: TAGAN TG530-U15 fuse blow possible pfc cause

The burnt resistor has been there, if i remember correctly, since the time i recapped the psu and then it run for some years until the FET sorted. It may be worth to do recap on your situation.

Kiriakos the repair at the moment is an easy fix as i can just disable the PFC or just replace the FETs and it will get it back to life. The thing is that it has been running for many years 24/7 and there are components as the filter capacitors and other which are more expensive to replace and may fail in a sort time.

[Kiriakos GR]

Re: TAGAN TG530-U15 fuse blow possible pfc cause

PFC is all about a small correction regarding Mains input voltage which saves few Euro over time regarding power consumption.
If you are capable to make it work with out this board , just do it.

[goodpsusearch]

Re: TAGAN TG530-U15 fuse blow possible pfc cause

As for whether or not these are worth repairing, well, these were probably one of the earliest modular PSUs and their feature list sounds impressive, they came with good quality cables and accessories, but I really think that their design isn't very good. They have bad quality caps, their fan runs at a slow speed in order to achieve quietness and they get really hot as a result while working. Perhaps they're worth recapping, but nothing more.

+1

What he said... I got the 330W unit: Every cap on it was bulging, even the main caps and its switching transistors were shorted. The APFC add on board was also shorted.

link: https://www.badcaps.net/forum/showthread.php?t=12484

[sententia]

Re: TAGAN TG530-U15 fuse blow possible pfc cause

Hello,

I found some time to solder the rectifier bridge straight on the main pcb and the PSU is working fine now... Sweet!

under the main pcb there seem to be a point where it looks like is supposed to touch the metal case of the psu. It is in a red circle...

The small fan control circuit has a transistor that i cannon find much about it...

P.S. i ordered the APFC mosfets so in time i will try to fix the APFC as well....

[sententia]

Re: TAGAN TG530-U15 fuse blow possible pfc cause

Most common failure mode for the MOSFET is the shorts between Source and Drain, if it show 0 Ohm on S & D when tested on board, then you should verify again with it off the board.
This is the typical PFC circuit:
https://cdn.badcaps-static.com/pdfs/...0c7ba8e0b1.pdf
You should check the all the active components, The PFC IC can be damaged also when the MOSFET failed (Gate to Drain shorted).

I received the PFC MOSFETs and replaced both (only one was shorted).

Installed the PFC in the PSU and everything test fine. All voltages are ok so there doesn't seem to be any more damage, PFC ic etc.

Thanks again budm!