2WIRE 3600hgv power suply

[ravenor]

I was opening a 2WIRE power supply to check the voltages as the gateway wasn't too stable lately. However, after I opened, it wouldn't work at all. The 2WIRE would power on for a second or so and display a red power light and then turn off. I checked the voltages with a multimeter and the voltage would be about 6v when the light was on and almost 3v when the light was off. Any ideas as to what would cause this?

[selldoor]

Re: 2WIRE 3600hgv power suply

Check for cold joints and replace the two small caps with quality caps.
VERY CAREFULLY check the voltage at the BIG CAP. Meter on DC600v

Please update your profile with country and mains voltage.

[ravenor]

Re: 2WIRE 3600hgv power suply

I want to wait until I have a bigger list of capacitors to buy as the shipping costs for just two or three capacitors is a bit high compared to the price of the capacitors themselves. The voltage on the big cap fluctuates from 166.4v-167.4v. I can't tell if any of the joints are cold because it was made using leadless solder.

[selldoor]

Re: 2WIRE 3600hgv power suply

OK - let us know how it goes, Actually I have a similar PS to fix -I dont need it so never seem to get round to it.

[ravenor]

Re: 2WIRE 3600hgv power suply

Is there anything I can do or test without buying new equipment? What are the possible causes for this fluctuation. Also, when the voltage fluctuates, there's a tiny click from the power supply but I'm not sure where.

[selldoor]

Re: 2WIRE 3600hgv power suply

What fluctuation - voltage on the big cap or the 3 -6 on the output?

[ravenor]

Re: 2WIRE 3600hgv power suply

Actually, the fluctuation in the output coincides with the fluctuation on the big cap.

[joshnz]

Re: 2WIRE 3600hgv power suply

the psu uses the primary filter cap as storage of mains voltage when the psu try's to start the caps voltage will drop then return to the peak voltage of the mains supply.

The output voltage fluctuation is a result of the psu trying to start.

[ravenor]

Re: 2WIRE 3600hgv power suply

What would cause the psu to be unable to start?

[redwire]

Re: 2WIRE 3600hgv power suply

Does it put out the correct (12V?) with no load? It's normal to see a volt or two fluctuation on the input filter cap, as powerline voltage moves up and down.
Check the bridge rectifier, I've seen an open diode make a power supply weak and go into UVLO (under-voltage shutdown) when loaded down. The bridge is on the heatsink, with 4 diodes to test.
Otherwise I've seen bad capacitors (the smaller ones) cause a supply to go unstable. Some of the solder joints look poor and I would touch them up too.

[ravenor]

Re: 2WIRE 3600hgv power suply

It outputs about 11.5v-12v with no load. How would I check the bridge rectifier? Sorry, I'm pretty new to this. What solder joints would you recommend I reflow?

[selldoor]

Re: 2WIRE 3600hgv power suply

As you are getting fully rectified voltage at the Big Cap it is unlikely to be a problem with the Bridge rectifier - they tend to work or not work.
Have you tried the supply on anything else - could it be a fault on the 3600hgv. A 12v car sidelamp is handy to have for testing.

[ravenor]

Re: 2WIRE 3600hgv power suply

Actually, the 3600hgv works fine with another 12v power supply.

[jetadm123]

Re: 2WIRE 3600hgv power suply

I almost willing to bet my lunch money it's one of the two filter caps (green and black ones on the right side) has gone bad. Is one of them a 1000uf 10v cap?

[ravenor]

Re: 2WIRE 3600hgv power suply

Well, the blue one is a Taicon 1000uf 25v cap while the black one is a 330uf 25v Ltec.

[ravenor]

Re: 2WIRE 3600hgv power suply

Is the 1000uf cap likely to fail?