Dell D635EF DELTA DPS-635AB PSU with blown TNY280PN

[Dynamite76]

Recently I got a DELL PSU from a presision T3600. It is a 635W PSU which went out with a bang and some black smoke. The model of the PSU is a D635EF made by DELTA.

The cause of the bang was a blown. TNY280PN Chip. How ever as a result or as a causo also two SMD resistors are smoked. I have been able to replace the TNY280 Chip but I do not know the values of the resistors. The resistors are within the Drain line of the TNY. I can not find the schematic of this PSU. THe resistor are Open Loop and on the voltage accross them is about 330V. (EU)

Any suggestions for the value of these resistors? Or am I mistaken and are these other components?







Your help is kindly appreciated

From some other forum I found that sometimes dell uses low value resisters like 68 ohm in the drain line. One of the resistors looks like an 0 ending so this could underline this low value...?

[Dynamite76]

Re: Dell D635EF DELTA DPS-635AB PSU with blown TNY280PN

I have a bit of update on the problem as mentioned above. I have replaced the resistors with two resistors of each 100 Ohm in parallel.

Now I have the main voltage level over the S->D pins, about 5.82V over the BP/M -> S pins and almost 0V over the EN/UV ->S pins. At the 5V side of the transformer I measure approx. 3.2V over the diode. At the 5V outlet I measure about 1V.

The CAP near the two blown resistors also got an impact. I desoldered this cap but is was not shorted and gave some capacity readings on the multimeter. (Forgot the value) But maybe this is the culprit?

Any sugestions for further repair or trouble shooting?

[R_J]

Re: Dell D635EF DELTA DPS-635AB PSU with blown TNY280PN

Replace that electrolytic on the BP/M line (next to the resistors) Check for short on the EN/UV line, if there is an optocoupler on that line it might be shorted, if there is no short, check that the high value resistor (3~4 megΩ) between EN/UV and the main supply is not open.
The two open resistors between +330vdc and the drain are likely acting as a fuse so there value will be low.

[Dynamite76]

Re: Dell D635EF DELTA DPS-635AB PSU with blown TNY280PN

Is the value of the cap near the resistor critical or do I have some freedom to choose. As I don't have a wide range available and should or one. Even then a suggestion for the value would be helpful as the reading on the cap are a bit unstable.

[Dynamite76]

Re: Dell D635EF DELTA DPS-635AB PSU with blown TNY280PN

I have replaced some caps and the zener diode which was also blown. Now i have 5v on the output but yet no 12v and no green diagnostic light. Any suggestion how to troubleshoot this psu any further?

[CapLeaker]

Re: Dell D635EF DELTA DPS-635AB PSU with blown TNY280PN

what happens if you force the psu on? Check the voltage on the main filter capacitor on the primary. What supervisor IC does it have? Look if the supervisor is turning the psu off.

[Dynamite76]

Re: Dell D635EF DELTA DPS-635AB PSU with blown TNY280PN

The supervisor chip is a dwa 103n-anp. When I manually switch the psu on I get an error signal from the supervisor. It also looks when I turn the psu on the tny280 is running hot…? When I push the button I hear a very soft noise.

[Dynamite76]

Re: Dell D635EF DELTA DPS-635AB PSU with blown TNY280PN

On the output of the PSU I measure 4.98 on the +5V line 0.09V on the -12V 0V on the FAN Ctl and POU line 4.98V on PSU ON 0V on the alert and 4.985 on the PSA A1 and 0V on the PSA A2 line when I turn the PSU ON the PSU ON is (obvious) 0V and the alert rises to 4.98 V.

[CapLeaker]

Re: Dell D635EF DELTA DPS-635AB PSU with blown TNY280PN

When the supervisor turns the primary off, there shouldn’t be any whining noises from the PSU. Unless there is nome thing wrong with the stby circuit.
Make yourself a incandescent dim bulb trick (put a 100W incandescent bulb in series with the phase wire). Check for shorts on the secondary and check the main filter cap on the primary. Maybe add some straight shot, high resolution pictures using the attachment function so we can see something.

[Dynamite76]

Re: Dell D635EF DELTA DPS-635AB PSU with blown TNY280PN

I will take some overview images later today. On the 5v side I had to replace the tny280 as it exploded, the zener diode next to it on the EN line was toast. Also I have replace a SMD cap and two reactors feeding the 5V circuit. After replacing these components I got 5V back again. But not sure if every is ok with this circuit now… the value of the smd cap is a bit depending if the measurements on the old cap where accurate.

Here are some detailed pictures I have on my phone. Other pictures I will share this evening.
This image indicates the components replaced in the 5V circuit

I am not sure on the feedback opto if they are OK

The supervisor

For the Record:
- I have replaced the Zener diode with a 1N5234B Zener diode 0.5W 6.2V
- I have replaced the SMD cap with a 2200 PF SMD 1206 -> This value I am unsure, also bought a 0.01uF
- I have replaced the SMD resistors with 2 x 10 Ohm 0,75W 1206
- I have replaced the CAPS with 47 uF and 10 uF (Just to be on the save side)
- I have replaced the P6KE160A Diode (But this did not change anything, original was most probably OK)

[Dynamite76]

Re: Dell D635EF DELTA DPS-635AB PSU with blown TNY280PN

In relation to the information provided above I have made some images and measurement for further debugging. Any input would be welcome.

First of all some photos of the complete PSU and some detailed shots:

Front of the Board Back of the Board Half of the back Half of the back
Half of the front half of the front Output strip of PSU 12V driving circuit?
5V circuit with replaced components Supervisor chip and back side of 5V circuit

On the supervisor chip I have made some measurements. When the PSU is OFF and ON pin 1 PGI is 0V, pin 3 FPO OFF 5V ON 0V, pin 4 PSON OFF 5V ON 0V VDD is 4.5 V.

On the TNY280 I have measured 1V over EN -> S, 5,8V over BP -> S and about 323V over D -> S. The voltage over the main caps is now 324V.

When plugging in the PSU i hear a bit of buzzing noise comming from the 5V transformer. I sounds the first few seconds as a bit on / off and after that a more contineous humm. The TNY280 is running quite hot...

For the good observer, there is a bit of a burn mark on the bottom side of the board in the main section... this was a human error with a ground wire. The performance of the board was not different afterwards than before...but maybe I am mistaken...

[CapLeaker]

Re: Dell D635EF DELTA DPS-635AB PSU with blown TNY280PN

Supervisor looks ok when psu is off and it also doesn’t care much about the standby rail unless there is no Vcc. For now the stby works, so concentrate of the rest of the primary and secondary.
You can override the supervisor and force the psu on, however you need to have that lightbulb in series trick, otherwise you may risk a bang. Keep checking the PFC, mosfets, diodes, make sure there are NO shorts in the primary nor secondary. I do know that when the main filter caps are bad, the TNY pops and also the supervisor will turn the whole rig off. You can look at a PowerMan IP PSU that I repaired and how that went along.

[momaka]

Re: Dell D635EF DELTA DPS-635AB PSU with blown TNY280PN

I do know that when the main filter caps are bad, the TNY pops and also the supervisor will turn the whole rig off. You can look at a PowerMan IP PSU that I repaired and how that went along.

^This

Remove the two primary caps and measure them out of circuit (capacity and ESR.) Make sure to discharge them first, of course, if they don't discharge by themselves. I made that mistake and have blown some parts before. Also shocked myself a number of times.

Dim bulb trick will work fine for testing the 5VSB circuit, but likely won't work well with trying to force the PSU On - APFC in ATX PSUs don't work well with low-Wattage bulbs. So once the 5VSB is up and running properly without the TNY280 overheating or humming, switch the series incandescent bulb with a 300W halogen... or a high-power resistive heating element (toaster, countertop oven, hair drier, heat gun, and etc.) - something in the range of 300-700 Watts. With this, the APFC shouldn't complain.

[Dynamite76]

Re: Dell D635EF DELTA DPS-635AB PSU with blown TNY280PN

With the main circuit caps you mean the two big ones... 330 uF...?

[CapLeaker]

Re: Dell D635EF DELTA DPS-635AB PSU with blown TNY280PN

Yes.

[Dynamite76]

Re: Dell D635EF DELTA DPS-635AB PSU with blown TNY280PN

Ok, thanks for the feedback. In the mean time I de-soldered the optocouplers on the feedback side, as in circuit they gave me some strange readings. But they are ok as far as I can measure. And while testing I found that one of the caps I replaced was shorted… there was a tiny little solder bridge between the cap pin and a nearby exposed line…. The devil is in the details. So once I put the optos back I will test it again and hope to have a more stable 5V without overheating and maybe more…

[Dynamite76]

Re: Dell D635EF DELTA DPS-635AB PSU with blown TNY280PN

One step forward the 5V circuit is now stable. If I push the on button the on board relay is switching. Unfortunately still no output on the 12v. The boosted power is rising from 350 when the psu is off up to about 390 when the psu is on. My “feeling” is that these main caps are still ok. But I know feeling does not rule out facts. But I would like to rule out some other things in the 12v circuit before touching the big boys. Any suggestions on how to trouble shoot for the next steps?

[Dynamite76]

Re: Dell D635EF DELTA DPS-635AB PSU with blown TNY280PN

I have debugged further up to the Uc3895 chip where is see no voltage over the bed and grind pins… but I don't know where this vdd is coming from… traced it back to a transformer… left one on this photo

[CapLeaker]

Re: Dell D635EF DELTA DPS-635AB PSU with blown TNY280PN

You got a supervisor chip I stalled now?

[Dynamite76]

Re: Dell D635EF DELTA DPS-635AB PSU with blown TNY280PN

Supervisor readings are: pgi pgo 0V fpo and pson 5V when psu off all 0V when psu is off