1000VA UPS

[am.steen]

I have a 1000VA UPS not working
I changed the 4 output mosfets but not working
The problem is that on AC it charges battery but no overcharged it continue to charges forever
And when AC is Off it is not running.
When press front panel button for 5 sec. it starts to work but no output and shows
red battery led and first green led for 2 sec then off again.
there is one burned resistor I changed it with 4.7R resistor beside CN5
I do not know from where to start

Please help
U11=mc68hc705p6acp
U3=MC14066
U4=LM324
U7=ULN2004
Attached photos and circuit diagram

 

[Delta Prime]

My friend what have you done! it's okay you can tell us everything;no one else will know!
You need to disclose what you're doing cuz this is very dangerous! Contrary to popular belief, you just cannot change the value of the fuses willy-nilly!
I'm not trying to beat you up.
I'm trying to protect you.

 

[Bluejets]

No idea how you arrived at the idea that the fuses are too large.
I don't see any reference to size on the schematic.
Being a 1000VA unit, one would expect to see fuses of this size on the DC input anyhow.

I'd have to say the burnt pins would be your first problem.
The rest of comment #2 is rather dramatic to say the least.

 

[am.steen]

Sorry for everyone may be mistake in my request
The fuses are the original ones which comes with the UPS i never change them as they are working
The small burned resistance is not shown on diagram so I replace it with small one
The MOSFET IRF540 is the original one I did not change as it is measure good as I say I changed only the 4 output MOSFETS with irz44
As they were bad

Can any one help me to fix it ??

 

[Delta Prime]

The fuses are the original ones which comes with the UPS i never change them as they are working

Then I'll have to take your word for it.Because the fuses keep changing color on me and values from 30 to 40 amps green to Red respectively.

as I say I changed only the 4 output MOSFETS with irz44
As they were bad

Could you please provide a photo of the four output mosfets.

The small burned resistance is not shown on diagram so I replace it with small one

Do you mean the 47 ohm resistor that looks like it has been cleaved or sliced with an exacto blade along with the hairline fracture on the side of the resistor?
I need to see the other side of the board the component side where the red circle is thank you. My methodology of helping you is just to catch whatever jumps out of me.
I'll be back at lunch time it's morning here where I am and thank you for the photos.

 

[am.steen]

Thanks Mr. Delta I appreciate your help
For the burned resistor I do not know its value as it was completely burned so I replace it with the smallest one I have.
The problem is that I get this circuit diagram from internet so it is not exactly as real circuit so I do not find this resistor value in it
Other photos are in attachments

 

[kellys_eye]

Did you replace that burned capacitor where the resistor was?

Looks like that green resistor was trapped between the board and the chassis - this could have created a short circuit and caused all sorts of damage.

Equally, you can't just use 'any old value' to replace it. The wrong value could either stop it working or cause more damage depending on how/where it is in the circuit.

Do you still have the remains of the old resistor? It might have been a varistor rather than a resistor.

 

[am.steen]

No I did not change the capacitor yet and I do not have the old burned resistor.
May any one have same ups give me photo or value for this resistor ??

 

[Delta Prime]

Would you have any documentation to go with that schematic?
How did you come across that schematic?
That little resistor you mentioned
Is R3 . We need to find the component values!
Capacitor C5 is destroyed.


Now, the two two pin connector CN5 has a fuse (F1).
I don't see it on the board maybe you can find it for me.
Show me where the female portion of the connector terminates too.
And you have to clean the board both sides or at least dust It off I can't really see anything in detail isopropyl alcohol would be excellent. Just do the best you can.
If you can and if it's not too much trouble retake the photos of the clean board and components I know you doing the best you can take your time.
I love my 2-hour paid lunch.

 

[davenn]

Guys,
please keep it friendly

have removed all the off topic stuff

 

[Delta Prime]

Common mistakes people make
When trying to repair electronic equipment is replacing components that do not supply
sufficient current to the load or allow excessive current to the load, inserting different value fuses other than the ones that circuit board is originally designed for is one mistake.
In doing so, noise immunity for the load and current senseing circuits are destroyed or accurate current sensing is severely diminished which
apply stress to support circuitry which will fail sooner than later.
This is why component selection is critical.
The traces on the printed circuit board themselves are designed to carry a maximum current capacity including vias.
At higher operating frequencies, bypassing the component tolerances, and values the inductance become a more sever problem.
Most people do not understand or do not wish to understand the implications of designing printed circuit boards for multiple variations.
There specifications; power requirements, power factor correction,real power,apparent power.
It is why the schematic you provided omits the component values themselves.
A perfect example is right here.
Same board is used different value components for different inputs and outputs voltage, current requirements. A lot of times same board component layout architecture but more robust traces.

All they have to do is Mark the version this particular piece of equipment is capable of and designed for.

 

[am.steen]

I get the schematic from this site

http://electro-tech.narod.ru/schematics/power/ups/KIN-1500_KP-801/KIN-800-1500AP_KP801-schema.gif

it is nearly the same ups with different brand name.
I can not find another schematic anywhere.
All your notes is right but I do not change anything except resistor and the old one is completely burned so I can not even Guess its value
And I did not change the capacitor as I do not know its value too.
# female portion of the connector CN5 terminates to main output transformer
# there is no fuses connected to cn5
I upload photos for board After clean

I repair many electronic devices but this is the first time to repair a UPS

Any suggestions ??

 

[Delta Prime]

All your notes is right but I do not change anything except resistor and the old one is completely burned so I can not even Guess its value
And I did not change the capacitor as I do not know its value too.

Respectfully, I am not accusing you of subterfuge.
The visual information you have provided the photos and schematic are an asset.
The link along with you're updated photos will help tremendously.
I will conduct research for that particular unit and hopefully more information can be obtained.
Thank you for your response.

 

[kellys_eye]

Assuming the schematic is correct then C5/R3 form a simple 'snubber' circuit. 47ohms wouldn't be out of place there and a 100nF to 560nF (any value inbetween) rated at 400V and specified as a class X2 capacitor would probably do for a replacement.

What you CANNOT do is mount the resistor UNDER the board as it has had part of its insulation covering scraped off (or compressed into nothingness) by being trapped under the board and pressed against the chassis. For the resistor on the TOP (component side) of the board and bend the leads to approximate the path the tracks would have taken.

Difficult to say what failed first - I suspect the capacitor did. When it failed it went 'short' at some point then caused the resistor to burn out as it had a lot of AC connected across it and it wasn't rated to handle it.

That said, removing the resistor AND capacitor shouldn't stop the inverter working but both parts really should be changed. That capacitor is probably still shorted.

 

[Delta Prime]

it is nearly the same ups with different brand name.

Use the schematic as a guide we need to verify where C5 and R3 are connected to or terminate. Along with CN5. You are more than likely have to make your own schematic. And use the reference designators for example capacitor,C5 and resistor, R3 and relays RY1, RY2, normally open, (NO) normally closed (NC) etc.
C5 and R3 series connected makeup what is called a snubber circuit and it's normally used in conjunction with relays and or other mechanical switching circuits. If you randomly pick a resistor value to put in its place would be a poor decision. It will not suppress inductive ringing
. In this case it would be ( poor engineering practice)called shotgunning! I would advise against it.
Get a multimeter do some resistance checks from point A to point B and verify the connections and please discharge those capacitors before you begin. Start by concentrating on the below photos.thank you.

 

[Delta Prime]

And you have to watch out on schematic symbols of a MOV
Metal Oxide Varistor

The MOV in the schematic below looks surprisingly similar to the thermistor in the component chart.thermistors are normally placed in series to
The circuit it is protecting. While the MOV is obviously placed in parallel.

SSZTBC7 Technical article | TI.com

Power Tips: Calculate an R-C Snubber in Seven Steps

e2e.ti.com

 

[Delta Prime]

I noticed that capacitor has a class X2 designation, obviously it failed, could be for many reasons if there was a surge on the electrical service mains,you're quality of the grid voltage, comes into question?
Therefore I would recommend a capacitor with a class Y1 which are impulse tested to 8 kV as opposed to and impulse test of 2.5kV for class X2 capacitors.




That 240 volts is the rms value.
Peak value = square root(2) x RMS value
So your peak Voltage = 1.41 x 240 = 339.41 volts.
Perhaps an overabundance of caution ; if you could find a class Y1 capacitor for a good price I would purchase it.

Description on X1, X2, X3, Y1, Y2 og Y3 – Capacitors – SDEV

www.sdev.dk

 

[73's de Edd]

Sir am.steen . . . .

Your best info was your very-very last small snippet
Here is a blow up of it, so that all can see the initial pristine image and inspect it . . .

http://electro-tech.narod.ru/schematics/power/ups/KIN-1500_KP-801/KIN-1500_KP-801_v3_3.jpg

( Go right young man . . . GO to the right ! . . . . . . Dress right dress . . . .HUH!)

NO PROBLEM IN MY MIND . . . . . in saying that bands 3 and 4 are SILVER and GOLD. Now bands 1 and 2 are being darker colors . . . I don't see RED, ORANGE,YELLOW, GREEN, BLUE, VIOLET, and probably/possibly? not GREY, and its definitely not WHITE . . . . . therefore I want to see BROWN for 1 and BLACK for band 2. (WHASSAMATTAHYOU?YOUDUMBCLUCK! . . . . . they aint's uh bein's no BLACK then BROWNS !)
WHAT ! I see being done, is there was being a production change and the initial F7 fuse being changed to this value of FR1 FUSIBLE resistor.

COME GO WITH ME . . . . . . . AND LETS GO WITH THE FLOW . . . . .

Referring to the units schematic, and specifically, the battery charge circuitry . . . .
I see AC line into AC power transformer that outputs ~ 18'ish or so Volts AC that then enters at CN5 wires . . . into this BURNT UP fusible resistor . . .not F1 but now being a FR1 . . . . that also, in ITS FLAMEOUT ***** , also totally torched the side of an X2 AC line safety capacitor . . . REPLACE! it, as being one of your required tasks . ( But not being THE problem .)
Then AC goes into discrete a FWB made up of D2-3-8 and 9 to then to pass thru power steering diode D7 and get initial filtering to purer DC via C10 main storage reservoir capacitor . Outputted DC then passes into series regulator transistor Q4 with some back EMF protection provided by D10 across its C-E junction.
Emitter output of Q4 is the regulated battery charge voltage that initially passes thru D6 series steering diode and passes on to the final BA + terminals.
Battery in / out switching is accomplished at neg battery terminal.
The unit uses a series wired (2X)12VDC = 24VDC lead acid sealed pair . . . a la . . .

With no AC load connected to the UPS output , it should be pulling about 16 watts from the battery set.
Now . . . . . going back to the battery charger circuitry at the Q4 emitter V0, where the R7-R38-R39-R51 voltage divider chain, is going into Q8 base, which establishes rudimentary charge regulation . . . . ALONG WITH . . . . a correcting digital variable P/W signal from u/P pin 11 that feeds into Q10 base .
Then Q10's degree of conduction of C-E via R37 then trims in paralleled R38 to adjust to transitioning battery charge states.
(And . . . . . LOOK MOM ! . . . . . . . no Snubber resistors or capacitors are even being involved.)
NOW one final look and referencing . . . . . and that will be the Q7 power FET . . . . . . note that it is being directly SOURCE-DRAIN across your pulsating DC supply.
If you have a CAT ASS . . . . and that's being HEAVEEEE on the CAT's ASS +TROPHIC condition, port C2 pin 20 of u/P feeds up into ULN 2000 series pin 7 and outputs as pin 10 and into R 27 and output of R27 as supplying gate drive to fully turn on the Q7 FET to put a direct short across that pulsating DC supply.
NOW . . . . . any one ready for a fuse blowing action ?
Since you found no cracked case on Q7 and its testing O.K. . . . . . I'd just keep a voltmeter monitoring on that Q7 base, in any future power up or testing.
Also, the first thing that you need to do is test the PRESENT state of charge on each of the 12v batteries. That's with a load on them like you might obtain by using a 12V brake light bulb, which typically pulls ~ 4A. (Choosing its heavier filament . . . . as its smaller park/turn only pulls about 700 ma.)
If needed . . . . as it probably will be . . . . use a cars trickle charger or LAB power supply to bring up the batteries to full charge.
That may be all that is needed to get the unit to turn on.
Then we can see if the IR44's were being a proper sub.
Thaaaaaasssssit . . . . . . . now, talk to me . . . . . babycakes\

***** earlier reference
I noticed that capacitor has a class X2 designation, obviously it failed, could be for many reasons if there was a surge on the electrical service mains,you're quality of the grid voltage, comes into question?



73's de Edd . . . . .

Sundays are always a little sad . . . but its not being the worst day . . . because the day before is always a sadder day.

.

 

[Delta Prime]

If you have a CAT ASS . . . . and that's being HEAVEEEE on the CAT's ASS

See what a wonderful community can do for you when everyone comes together. enjoy!
I know I did.






My technique is called self-deprecation now everybody feels good about themselves but they don't know why?
Two steps ahead people.
The in-depth information provided; resources, documentation,will help you in the future. Serendipity.
Low hanging fruit.

 

[kellys_eye]

The OP might appreciate this link:

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