X-Power ATX 700W TD

[capamatic]

Hi,
Wonder if anyone can help me with this ?
Acquired 2 of these units, both dead. Loaded with a couple of DVD Drives and shorted the PS-ON pin, not even the fan spun up.
They seem completely new, no signs of cap failure (mostly Teapo, Suscon)
No obvious board damage nor component failure, internal fuse OK.
As both units have similar symptoms, methinks common failure. DOA ?
I struggle a little without schematics and repairing PSU`s is new to me.
Would greatly appreciate pointing in the right direction.
Many thanks.

[i4004]

Re: X-Power ATX 700W TD

https://www.badcaps.net/forum/showth...ighlight=i4004

check sencore and repair articles first.

i would first check stby supply and then take it from there...
(i see it's ic design so locating the datasheet can help you with checking that circuit..see attached jpg)


on hardwaresecrets web site you have psu article which shows what's where.
here
http://www.hardwaresecrets.com/article/327

so read, measure, desolder a thing or two and you'll have results soon.
be carefull, these voltages can be dangerous: prefer to do most of the work with psu unplugged, if possible.

[kc8adu]

Re: X-Power ATX 700W TD

i dont see 700w worth of stuff in there.

[Krankshaft]

Re: X-Power ATX 700W TD

i dont see 700w worth of stuff in there.

I agree but Yum Cha supplies like this always lie about the wattage.

Maybe thats why they died someone actually tried to pull 500 watts nevermind 700 .

Hmm a space shuttle on the box eh? Well I bet its about as reliable as one .

As for the supply the design looks pretty straight forward on the riser board in the middle you have your PWM (the driver for the chopper FET) and on the riser board by the wires you probably have your power good generator IC.

As for the caps I've seen Teapos last in PSUs but Su Scons are known crap.

As for the IC you labelled standby power chip that looks like a TOP IC bascially its a FET and PWM all on one chip. I love these ICs because replaceing them gives you both in one. If that IC has a T logo on it then thats what it is.

Do you have standby voltage when the PSU is plugged in.

Plug in the PSU and flip the power switch on (if it has one) and measure from a red wire on the ATX connector to ground you should have 5 volts.

From my experience if the fuse is ok and the chopper FET tests good then odds are its the PWM circuitry (driving the chopper FET), Power Good Generator IC (fault in the cirucitry not allowing to PSU to come on) or feedback problem (causing improper output voltages).

[JEWilson]

Re: X-Power ATX 700W TD

FWIW

I have repaired a number of these ATX ATX-600TD
If completely dead and cannot force PS-ON.

First, I believe you have checked the ESR of the small
caps, the remaining O/P lytics should be Teapo.
Check the ESR of these in any event.

Second, check fuse - will require to be removed from PSU
If dead, replace. Fuse type 250V T5.00A in the UK.
Test if PSU powers on. If not, test the replaced fuse as above.
If again, dead very probably infers one or both of the
2SK2611 MOSFETs are shot. It is likely these
are present on the 700W model.

Third, remove the pcb from the supply housing.
Check if any physical stress or component damage
evident. Check solder side for similar.

If no visible signs of distress, fourth, test the MOSFETs
attached to primary heatsink - Q6 and Q7.
To do this remove the heatsink with the MOSFETs attached.
I have found the LHS side device Q6 to be damaged where
the PSU exhibits these conditions in line with Krankshaft's
observation re - feedback.

Note, it may be the opto-coupler has also gone to meet
its maker, replace as appropriate. Check device condition
of resistors and diodes as appropriate this area of pcb

Report results please.

[i4004]

Re: X-Power ATX 700W TD

>As for the IC you labelled standby power chip that looks like a TOP IC bascially its a FET and PWM all on one chip.

yes, that's how stby power is produced. pwm ic and switcher(aka chopper) in one package.
they can do that because it's not very high wattage, so the switcher inside the chip can suffice.

that design doesn't look too bad at all, but yeah, 700w is just a gimmick, it seems.
probably doesn't have half of that.

[capamatic]

Re: X-Power ATX 700W TD

Thanks for the tips
I`ll check them out and post back.

[capamatic]

Re: X-Power ATX 700W TD

OK, found some time to investigate further.
I have +5V on the standby (purple) wire, no voltage elswhere on the ATX connector.
Desoldered the primary heatsink, checked the FETs and diode - OK
Checked the small value (100uf 25V) caps around the PWM chip, the ESR of these is 0.1 - seems strangely low
The power resistor has a strange colour code BLACK,BLUE,SILVER,GOLD,GREEN ??
Upon power-up, the unit sometimes crackles for a second then nothing (protection?)
Primary side seems OK, ESR`d the caps, continuity OK, may ring the transformers. Chokes/Inductors OK.
Solder side OK, diodes and resistors OK.
Not checked the OPTO`s yet (4 off)
It`s looking like a chip fault, the TNY267PN or WT7517.
I may desolder the secondary heatsink to check the fets, this will give better access to the output caps.
Will update.

[JEWilson]

Re: X-Power ATX 700W TD

Hi

This differs from the ATX 600-TD
On the primary heatsink, exists only 2 of 2SK2611 MOSFETs
As you can read +5VSB, then is a specific start-up problem.
Concur with next course of action

[i4004]

Re: X-Power ATX 700W TD

>It`s looking like a chip fault, the TNY267PN or WT7517.

if you have +5v stb then it's not tny as it's making that voltage.

welltrend
"WT7517
DESCRIPTION
The WT7517 is semiconductor integrated circuits designed of Server System switching power supply. It provides protection circuits, power good output (PGO), fault protection latch (FPOB), and a PSONB control.The Over Voltage Detector (OVD) and Under Voltage Detector(UVD) are monitorV33, V5, V12A, V12B within WT7515-N16 and external control VXOV and VXUN within WT7517-N18.The Over Current Detector (OCD)monitor IS33,IS5,IS12A and IS12B within WT7517-N16 and external control IX and VX within WT7517 shall restart power automatically. WT7517-N161 has FAN C function in OTP/FC pin. The output PWM is active low. "

that's psus "brain".

closest datasheet i could find is this
http://pdf1.alldatasheet.com/datashe...TC/WT7515.html

welltrend sux.

check it's voltages and see if there's anything choking it.

[capamatic]

Re: X-Power ATX 700W TD

Update :-

Desoldered the secondary heatsink
6 Schottky rectifiers, 3 different types (30A) tested OK.
Next step, solder it back up and test around the WT7517-164 chip.
If it turns out to be this chip, could be a problem locating spares.

[JEWilson]

Re: X-Power ATX 700W TD

Check the -12V rail as I discovered the 2.0A fast recovery rectifier
in the ATX 600-TD to be toast. As this is a discrete diode, it
was diffiucult to spot as;
1 The solder side joints look ok
2. Got a bad reading with my meter
3. The device was toast as, when removed, broke into two parts.
4. Device is a R206 diode.

It may be of course, your supply differs from the 600-TD in respect
of the -12V rail. But... having removed the secondary in the 600-TD
gave me the clue, as the lead was observably in poor condition but
under the lower arc of the largerst toroid (out of the way hehe).

Would not have seen it otherwise.

This might explain perhaps the protection issue you are experiencing,
short to common, PSU will stay off.

[capamatic]

Re: X-Power ATX 700W TD

Thanks.
I`ve been through all the diodes and all tested ok in situ.
I`ll run through them again to be sure.
The decoupling caps to the Welltrend IC were also fine out of cct.
Did find a ceramic cap with its lead touching a link, but was connected on the solder side anyway.
I`m still of the opinion the Welltrend IC is the major suspect.
There is a small daughter-board with the PFC cct (2 smd IC`s) which might cause problems, but I dont think it would cause no-start.
Is there a method to test if the output is shorted ?
Also, the Tiny11 IC`s Drain seems to connect only to the smaller T2 transformer, what controls and chops the main T1 transformer?. I have 5Vsb but this is derived from the T2 transformer.
Might just have to pull the whole thing apart and test it bit-by-bit.

[i4004]

Re: X-Power ATX 700W TD

>what controls and chops the main T1 transformer?.

main switchers are between t1 trafo and biggest cap on the board, they're attached to heatsink.

if control circuit is giving proper signal to optocouplers and after them, then these switchers should be suspicious.
but you need scope to see what's coming to o.couplers(4 pin elements between the 2 trafos....other 2 o.couplers(neard the edge of the board) are feedback for stby supply).
comparing it on scope with known good supply would be ideal, but you said you have 2, both dead.
anyway, perhaps even checking the voltage and/or frequency on dmm would be somewhat usable, for example if you see that voltage is on the input side, but not on the output...
http://en.wikipedia.org/wiki/Opto-isolator

with that test you can establish if control section is working, as a whole.

>Might just have to pull the whole thing apart and test it bit-by-bit.

you still can't test chips that way.

pfc section can cause no power allright.
inspect
http://en.wikipedia.org/wiki/Power_f...External_links
esp.
http://www.onsemi.com/pub/Collateral/HBD853-D.PDF

but given that you have stby power, it should mean 325V is coming to main switchers too, as it's coiming to tiny11.

[capamatic]

Re: X-Power ATX 700W TD

Having decided the Welltrend IC was faulty, I decided to canibalise this one, and use it as spares on the second (also dead unit).
This one had a blown fuse, a quick poke around revealed the input bridge rectifier to be shorted. Swapped it from the 1st unit and also the fuse.
Switched on and life !
Well, of sorts. I hooked it up to a little PSU tester (LED`s for the various Voltages) and all ok except no +3.3 and -5 .
Just wondering if this points to something common ?
Maybe the tester isn`t loading these rails ?
Help appreciated.

[capamatic]

Re: X-Power ATX 700W TD

Just found out that the -5V is optional on ATX12V 2.2 PSU`s. Used on legacy ISA cards apparently. So that sorts that one out.
Now onto the missing +3.3V ??????

[i4004]

Re: X-Power ATX 700W TD

if you have all other voltages it means primary side is ok.
so check secondary...diodes, caps, stabilizers etc.

[capamatic]

Re: X-Power ATX 700W TD

Turns out it was a loading problem with the tester.
Hooked up the SATA power cable and all voltages present and correct.

Thanks to everyone who helped.