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

[Petr0x]

Hello all,
my friend has issues with subwoofer Velodyne Wi-Q12 (actual PN Wi-Q12VBE, could be also similar as Wi-Q10 ).
He had it connected and powered at all times, not in standby mode, but in "always on" mode.
The subwoofer is made in 2013, so not 2024 it is 11 years old.
Once during night it started to make noises like helicopter (as he says). Then it may have stopped itself, however after that the subwoofer is completely dead. Absolutely nothing happens, no buttons react. The main fuse was blown, but after replacement still same.

I extracted the panel with boards and suspected the input power supply could be the issue.
Visually there is no problem, no capacitors blown, just few heat marks on the epoxy. That is probably after use and age.
After analysis I found out the power supply is made in a way that the main (high power) supply is switched on by relay, which is powered by smaller "always on" supply. That probably reacts on the mode switched on the main panel and switches the relay accordingly.

After measuring it seems the standby supply is the problem, there is no voltage on the small transformer output, therefore suspected is the standby power switch which is here LNK625PD. The coil seems fine, diodes fine, capacitors not shorted.

I will post photos and keep updated on the repair. Now need to order the IC and replace it.

[Petr0x]

Update on the Velodyne power supply.

I managed to buy and replace the LNK625PD standby DC/DC regulator, however the situation remained same - still not working, the relay did not switch.

Therefore I tested the secondary part for short circuits - looks OK. Then I put 5V at the capacitors on the secondary part of this standby supply and the relay clicked normally.
So I assumed there must be something I could not see.
Then I checked the LNK625 bypass voltage, that was 6V - OK. Measured the patterns of the secondary transformer on oscilloscope, there were sharp peaks, quite far away. I was not sure if that is OK. With almost no load on the secondary that could be OK.
However the secondary part I measured with another (better) multimeter, so I measured 1.4V on the first capacitor and 0.7V after the linear DC regulator. That is too low, but why?
Then I started randomly checking maybe the capacitors could be wrong, even they looked OK.
Bingo.
There were two 470uF/25V, one of them measured 390uF/0.7 Ohm another 250uF/4.4Ohm. The brand was Suscon, probably some low-end. So I assume the second was the culprit. I did not have exact value so I put much better ones, but only 100uF/60V and the power supply started and relay clicked, even there was no other connector put into the board (I assumed the standby is regulated by some signal from the audio board, but apparently default state is to power on the mains regulator at the power supply board).
Primary capacitor I also replaced before, it was something like 100uF/400V.

Therefore for anyone who is dealing with similar issues, I recommend checking the primary and secondary capacitors.
I used the aliexpress LCR tester "T10H" which is some newer model, much faster, bigger display and with built-in rechargeable Li-Ion cell.