Halogen lamp PSU keeps burning fuse !!

[SM-Piyes90]

Hello fellow members here on this board .


I have two lamp PSUs outputing two 41 Vdc supplies .

When i first got them i found a blown varistor as well as the fuse , the mosfets were good .

After getting new varistor and changing the fuse , i powered up the unit and bang the fuse and the two mosfets are bad .

The IC1 was taken for some tests but no clue on how to test it , its a IR2153 BTW .

Here is a picture of the unit :

[stj]

Re: Halogen lamp PSU keeps burning fuse !!

check every diode and the 2 small transistors and maybe even the polyester caps.
if you cant find anything wrong,

did you meter the transformer windings?

[SM-Piyes90]

Re: Halogen lamp PSU keeps burning fuse !!

Thanks STJ for that .

I had already measured all the RLC components and diodes , everythings seems to be fine

Now i am stuck at testing the IR2153 IC and i don't have unfortunately the material to check the stransformer .

What do you suggest ? at least ruling out one of those two .

[CapLeaker]

Re: Halogen lamp PSU keeps burning fuse !!

the easier one is to change out the IR2153 IC since they are driving the mosfets. Check the output pins LO and HO see if they are shorted? And the two resistors between them and the Mosfets.

[budm]

Re: Halogen lamp PSU keeps burning fuse !!

If the drive outputs of the IR2153 stuck on instead of switching on and off at high frequency that the power MOSFETs will just be full on and that will blow the MOSFET, shorted transformer can also be the cause but you will need Ringer to test the transformer.
The circuit used on this board is more likely to be from the app. notes of the IC.

[SM-Piyes90]

Re: Halogen lamp PSU keeps burning fuse !!

Hi again .

After my last attempt to see what s going wrong with the psu , i decided to remove the transformer and use the lamp fuse trick .

What i got is a 90 Vac drop on the lamp and the mosfets are getting pretty warm .

How much voltage should the lamp be dropping when everything is fine ?

[stj]

Re: Halogen lamp PSU keeps burning fuse !!

virtually nothing i think.
becaue the psu isnt drawing any real current - atleast when it works right.

[budm]

Re: Halogen lamp PSU keeps burning fuse !!

The power should barley draw current. What is the Wattage of the lamp?
What is your AC Voltage, 230V?
MOSFET should not get warm without the transformer connected.

[SM-Piyes90]

Re: Halogen lamp PSU keeps burning fuse !!

The power should barley draw current. What is the Wattage of the lamp?
What is your AC Voltage, 230V?
MOSFET should not get warm without the transformer connected.

Hi and thanks for keeping in touch .


The lamp wattage is 60W ( filament lamp ) , and the line voltage is 230 V .

Also one interesting thing is that one of the two mosfets metallic tap got a little brownish and real hot , the other one seems fine .

The other PSU act the same ( i have two by the way ).

[CapLeaker]

Re: Halogen lamp PSU keeps burning fuse !!

Umm... Change the cap out? You have anything to measure esr?

[SM-Piyes90]

Re: Halogen lamp PSU keeps burning fuse !!

Hi capleaker , actually this PSU has no primary caps , only secondary 50 V caps .

Last thing i noticed is that the startup resistors are starting to burn maybe primary problem .

Right now am going to remove the IC , and see if the primary diodes are outputting 320 Vdc correctly .

[selldoor]

Re: Halogen lamp PSU keeps burning fuse !!

41vDC seems an unusual voltage - do you know what lamps these are out of
(model Numbers) Here is a catalogue from Gimax lighting

Doesnt help much but does have a picture of your board on the last cover page.

[SM-Piyes90]

Re: Halogen lamp PSU keeps burning fuse !!

41vDC seems an unusual voltage - do you know what lamps these are out of
(model Numbers) Here is a catalogue from Gimax lighting

Doesnt help much but does have a picture of your board on the last cover page.

I totally forgot about that indeed , maybe this is supplied by a 24 V ac then transformed into a higher voltage .

I will try with a 24 volts supply and see what happens .

[SM-Piyes90]

Re: Halogen lamp PSU keeps burning fuse !!

Nice find selldoor , i was personally thinking the same . But the retards that gave me these said that they were using 230 Volts plug .

Anyways i have powered the card with 24 V dc .

I get 33 Vdc , 16 volts + 16 volts on the filtering capacitors , 9 Khz on the first mosfet's gate, 14 Khz on the other .


Could we assume that this a sign of a bad IC ?

[budm]

Re: Halogen lamp PSU keeps burning fuse !!

What is the Voltage rating on those two filter caps?
As I indicated in Post 5, the output of the Gate drive IC may stuck high due to failure and cause the MOSFET to be on all the time instead of switching them on and off at high frequency.
BTW, did they work before or you got this from some one else, and also which connectors did you use to apply 230V into the board, the two on the left side or the one on the right side as shown in post 1?

[SM-Piyes90]

Re: Halogen lamp PSU keeps burning fuse !!

What is the Voltage rating on those two filter caps?
As I indicated in Post 5, the output of the Gate drive IC may stuck high due to failure and cause the MOSFET to be on all the time instead of switching them on and off at high frequency.
BTW, did they work before or you got this from some one else, and also which connectors did you use to apply 230V into the board, the two on the left side or the one on the right side as shown in post 1?

The caps are 50v rated , and are in series . And i got the unit from a guy that wants me to repair it for him and said that he used a 230 Volts before the Varistor was burnt.


After replacing the fuse by a light bulb , i powered it with 24 V , and the IC outputs are delivering different frequencies ( 14.5 KHz and 9 Khz ) .

[selldoor]

Re: Halogen lamp PSU keeps burning fuse !!

Can you find out what type of bulb it is meant to power?
12v halogen? or maybe a 12v/ 24v cfl

[SM-Piyes90]

Re: Halogen lamp PSU keeps burning fuse !!

Can you find out what type of bulb it is meant to power?
12v halogen? or maybe a 12v/ 24v cfl

It is fed by 24vac rectified to 36volts then transformed to 41 volts dc to energize the light bulb .
There is actually two 41v outputs from the same psu.

[selldoor]

Re: Halogen lamp PSU keeps burning fuse !!

Hmm - this keeps on changing but you are back to 41volts.

Really need to know what bulbs it is supposed to light?

[SM-Piyes90]

Re: Halogen lamp PSU keeps burning fuse !!

Hmm - this keeps on changing but you are back to 41volts.

Really need to know what bulbs it is supposed to light?

Here is a picture i snipped from the PDF file you linked .

It is the one with the GIMAX sticker .

The PSU is supposed to deliver 2x41v to the cfl .