Lambda MML 400 Switchmode Power Supply Troubleshoot And Repair

Follow along on this troubleshooting and repair adventure of a Lambda Omega MML 400 switch mode DC power supply (SMPS). No schematics are available so let's see what it takes to track down the problems.
#powersupply #electronicsrepair #learnelectronics

[@garretr4488]

Great diagnosis! Lambda made some great supplies

[@EriksElectronicsWorkbench]

Thanks and yes they sure did make some quality heavy duty power supplies.

[@richardcarl6901]

Great video and well done trouble shooting!

[@EriksElectronicsWorkbench]

Thank you!

[@abdurrahmandemir2038]

Wow. Module is quite quality

[@sebastian_harnisch]

Thank you for another great video! One minor note for someone trying to replicate the high frequency AC voltage measurement: The 34465A is specified for up to 300kHz, but most hand-held DMMs are much more limited, e. g. Fluke 179: 1kHz, Fluke 87V: 20 kHz, Brymen BM789: 100 kHz. An isolated oscilloscope (consider max. voltage) or a HV differential probe can help here.
One more thing: Did you happen to measure the waveform/peak voltage at this cap afterwards? Would give some peace of mind that the selected capacitor with its voltage rating is properly chosen. (I'm pretty confident it is...)

[@EriksElectronicsWorkbench]

Thanks for watching! Yes you need to know the limits of your test equipment. I did check the voltage and waveform across the ceramic surface mount capacitor. It is a 94 KHz very narrow spike waveform with the spikes going to about 5 volts and it is riding on 3 volts DC. Note this is voltage across the cap, not referenced to ground, measured with a Fluke 199C isolated ground scopemeter.

[@coloradowilderness3139]

Really very helpful diagnosis !

[@EriksElectronicsWorkbench]

Glad you found the video helpful!

[@MrLinuxone]

Excellent !, I love your videos, thanks .

[@EriksElectronicsWorkbench]

Thanks for watching and glad you are enjoying my videos!