Velodyne SMPS, power transformer

[R_J]

Re: Velodyne SMPS, power transformer

You should be able to, but if those voltages are high, the voltage that supplies C14 etc. will also be high and they will likey also blow.
What is the number on U1? looks like IR2153 or IR2155

[R_J]

Re: Velodyne SMPS, power transformer

Something else I noticed in post #10

on the cold side to have blown or do you think the two diode bridges (Q3 and Q4, MUR6120CTRG, common anode)

This can't be correct, They can't be "Q" they should be "D" and they can't be the same, one would be common anode and one should be common cathode. Also the number does'nt look correct.

[PlayerOne]

Re: Velodyne SMPS, power transformer

R_J, can't thank you enough for catching that...you are absolutely correct. One of them is in fact common cathode. This would adequately explain C7 blowing, no?

Attached is a photo of the original parts, which I do not believe are available any longer...at least not that I could find. Another thread on this forum regarding the same SMPS mentioned the MUR6120 being used and its data sheet looked comparable.

Attached both data sheets as well to see if you agree MUR6120 is suitable replacement (there's also a version available with common cathode).

PS. With the topside having been expose to electrolytic fluid, do you recommend a thorough washing? It's single layer.

[PlayerOne]

Re: Velodyne SMPS, power transformer

You should be able to, but if those voltages are high, the voltage that supplies C14 etc. will also be high and they will likey also blow.
What is the number on U1? looks like IR2153 or IR2155

Sorry didn't see your question...U1 is IR2153 (attached photo of original part as well). My understanding is this switches the power transformer at frequency set by resistor and cap connected to it (probably 100Khz), but doesn't actually control the output voltage, correct? It has some feedback to control duty cycle only?

[R_J]

Re: Velodyne SMPS, power transformer

MUR1620CTRG should be fine. common anode. Looks like the circuit does'nt really have any fedback for regulation.
BUt having a common cathode diode on the negative side would definitely blow the capacitor.

[PlayerOne]

Re: Velodyne SMPS, power transformer

Thanks again, will get the parts on order and let you know how things work out once they’re installed. Hope you have a great Easter if that’s something you celebrate.

[budm]

Re: Velodyne SMPS, power transformer

So some one else worked on this power supply board and put in wrong diode? That is important information.

[PlayerOne]

Re: Velodyne SMPS, power transformer

Possibly or it could be that it just was not clear enough from what was written for me to avoid incorrectly thinking the rectifiers are the same. In any event, I have already posted this key point (that they are in fact different) in the other thread titled “Velodyne switching PSU ?“. Not sure if the folks contributing to that particular thread are still actively pursuing a solution, but I felt it was important to add this info there just in case they are or in case someone else working on the same board come across the thread. Hopefully it helps them avoid making the same mistake I made.

I will post additional info here as I work towards a fix for my specific SMPS.

[mirekkon]

Re: Velodyne SMPS, power transformer

PlayerOne: Have you repaired this power supply?

[nolaru]

Re: Velodyne SMPS, power transformer

PlayerOne i have same problem. the irf740 burn immediately when i take plug 220 volt.

[vladm74]

Re: Velodyne SMPS, power transformer

I fixed my Velodyne and made the SMPS scematic. Here you'll find how:
https://www.badcaps.net/forum/showpo...0&postcount=26