Velodyne SMPS, power transformer

[PlayerOne]

I need help in finding a schematic or otherwise identifying the electrical characteristics of a transformer in a SMPS having the following marking:

042-010214-000ZR
ELY 1317

A photo of the transformer is attached. In particular, this is a PCB mounted transformer and I need the pinout.

I've tried Google searches of various portions of the part number with no luck, however managed to find posts with photos of this transformer having the same markings, except for the numbers following the “ELY” which leads me to believe they must be date code info and not relevant to my search.

Appreciate any help from the community on this one.

[budm]

Re: Velodyne SMPS, power transformer

Why do you suspect that the power transformer is bad?
Show us good clear straight shot pictures of the whole top and bottom side of the board then we may be able to trace out the circuits.

[PlayerOne]

Re: Velodyne SMPS, power transformer

Thank you...appreciate the quick reply. I don't suspect the transformer is bad, but trying to recreate enough of schematic to help with trouble shooting the PS. Coming up empty on the transformer is making that difficult.

Thanks again...will be back shortly with pics of top and bottom of board.

[PlayerOne]

Re: Velodyne SMPS, power transformer

Just upload more photos of top and bottom of board. One of the big caps (C10) was completely blown has been replaced along with it’s twin next door. See photo of C10 after having been replaced...powering the board still causes main 3A slow blow fuse to open.

What do you see looking a the underside traces? There are what looks to be some bare spots showing copper runs in some key areas as well as a few spots that look to have been hand worked to add more solder (not by me).

[budm]

Re: Velodyne SMPS, power transformer

Check the resistance of the two power device (MOFET) on the heatsink in the hot side, also get the P/N as printed on the them.
Also check the bridge rectifier in the hot side.
https://www.badcaps.net/forum/attach...3&d=1585700632

[PlayerOne]

Re: Velodyne SMPS, power transformer

FET (Q2) has 0.5ohm between G and S and same between G and D. It has 0.3 ohm between D and S...guess that's considered a short?

FET (Q1) has 1.3ohm between G and S and same between G and D. It also has 0.3 ohm between D and S...guess that's considered a short too?

The part number of Q1 and Q2 are both FPD12N50.

Bridge rectifier (BR1) has 0.54V across each of the 4 diodes using multimeter set to test diodes..part number KBL406. I'm thinking this part is OK, no?

[budm]

Re: Velodyne SMPS, power transformer

See post #5.

[PlayerOne]

Re: Velodyne SMPS, power transformer

Thanks again...Post #6 updated with the resistive measurements requested..please let me know if I’ve misunderstood. My best guess is FETs are bad, bridge is good.

[budm]

Re: Velodyne SMPS, power transformer

Shorted MOSFET's at this point which causing main AC fuse to blow. You need to also check other component connected to the MOSFET to see if any of them are also damaged or not.

[PlayerOne]

Re: Velodyne SMPS, power transformer

Ok thanks, will probe around on components connected to FETs. Could this have lead to one of the big caps (C10=330uf, 100v) on the cold side to have blown or do you think the two diode bridges (Q3 and Q4, MUR6120CTRG, common anode) connected to secondary are also suspect?

Have FETs on order...thanks again!

[budm]

Re: Velodyne SMPS, power transformer

I would check the rectifiers on the cold side for sure to make sure they are still OK.

[eccerr0r]

Re: Velodyne SMPS, power transformer

Chances are, the IR2153 is fried too.

[PlayerOne]

Re: Velodyne SMPS, power transformer

Thanks, appreciate your guidance. I suspected the same since it switches the FETs and ordered a replacement along with the FETs, rectifier diode arrays (common anode) and replacement caps.

[PlayerOne]

Re: Velodyne SMPS, power transformer

Replaced Q1&Q2 FETs, Q3/Q4 rectifier diodes, all electrolytic caps (except for C24, next to J3, and C2, C3 big caps on hot side). Replaced 3A main fuse and tried to power it up...after several seconds, cap C7 (one of the large caps one the cold side) blew and vented smoke while leaking its electrolytic fluid out. Not good. I checked all discrete diodes with Fluke 87 meter in diode mode and all were good (roughly 0.4v to 0.5vdc).

The ‘event’ did not seem to fry any of the components replaced above...FET’s resistive measurements are in the couple 2-3 Mega Ohms min and same as the readings I got prior to trying to power the board. Diode rectifiers Q3&Q4 also look good, testing around 0.4vdc with meter.

Only thing it seems I did not replace was the U2 (MC7812CT) which I believe is 12vdc voltage regulator. I guess I’ll try replacing it next, along with the now blow C7 cap, but troubled by the failed attempt and not sure what else to check prior to another power up attempt. I’d hate to fry any of the newly replace components.

Any ideas from the community?

[PlayerOne]

Re: Velodyne SMPS, power transformer

U2 has been removed and has 36k ohms between pin2 (ground) and pin 3 (output)...same as that measured on the brand new component so looks normal. Pin 1 (input) to pin 3 (output) measures 8M ohm, which is same as the new component as well. Conclusion is U2 is still good and not cause of C7 blowing when power was applied.

Was hoping U2 was going to be clearly bad, but now I’m back to square one...not sure what’s going on.

Any thoughts greatly appreciated!

[R_J]

Re: Velodyne SMPS, power transformer

If C7 blew, it either had AC voltage applied (shorted secondary diode) Recieved reverse voltage (was in backwards) or the cap was bad (shorted?) Or the voltage was way too high, Check that nothing is shorted on the negative supply, If there is a short on the negative side it might have caused double the voltage across C7
This power supply secondary supplies + and - voltage, If C7 blew C10 should have also blown.

[PlayerOne]

Re: Velodyne SMPS, power transformer

Thanks, much appreciated...will check and double check. I was very careful to make sure I got the cap polarity correct for each cap that was replaced. C7 and C10 where both brand new components purchased from DigiKey and a reputable brand (Nichicon)...even so, not impossible to get a faulty part...although unlikely. C7 was definitely domed, but C10 looks to be in good condition with no sign of looking bad, although looks can be deceiving.

Do you have a pinout for the transformer? I can’t find any info on it and would love to know what the primary to secondary ratios are as well as polarity and number of windings.

[PlayerOne]

Re: Velodyne SMPS, power transformer

One of the other thoughts I had was that all I did was recreate the original problem, which was finding C10 blown. Perhaps this time it was just C7 that happened to blow first.

[R_J]

Re: Velodyne SMPS, power transformer

I doubt you will find any information on the transformer, it was likely a custom part. Check the voltage across the caps, C7 and then C10. I see you have installed 100v caps, what was the voltage rating on the originals?
U2 has nothing to do with how the power supply operates, it is just to supply +12 volts for another circuit. It's input is likely around +18v
If you find the voltage across C7 or C10 to be too high I would check the feedback ciruit. on the primary side

[PlayerOne]

Re: Velodyne SMPS, power transformer

Yes, the capacitance value and max voltage rating for C7 and C10 match the originals. Would it be OK for me to remove C7 and C10 in order to be able to trouble shoot? I’m finding it difficult to take measurement when the supply only lives for several seconds before popping C7.