AE#49 Repairing A Lambda LK 351-FM Power Supply

Here's an old rack mount power supply, a Lambda LK 351-FM which I got non-working for about a penny a pound. A few problems are found a fixed, and it comes back to life. A big Thank You to Lambda for promptly providing me with a full manual without which I would have been unable to repair this.

[emsbroek]

Thans for this brilliant informative video. I bought also two Lambda power supplies, they sold to me as broken and not working. Mine had also missing bridges between the S- with -DC and S+ with +DC.

After replacement both power supply's work properly.

[CliveChamberlain]

I just got a Lambda LK 343A-FM free! (~ 35lbs) I tested 36.5v at 11 amps out with under 50mV ripple! Solid stuff! They're really efficient since they phase-fire the transformer so the output pass transistors don't have to spew out so much heat.

[Berre]

I like your channel a lot. You have all kinds of peculiar electronic restoration projects going on. Besides, you have a wonderful way of telling interesting facts about these projects, so we get to know the history and the circumstances in which these objects were found. Keep up the good job.

[fullwaverecked]

Great video Arti! I recently scored a lambda 2095 AM power supply on our local classifieds, and it is also a beauty and a beast.

[emsbroek]

I liked your video, tomorrow I am lucky to pick up two lambda power suply's near Amsterdam. They both do not work, so hopefuly I learned from your video😀

[notJW]

Another great video. Thanks for making it!

[materialsguy]

Huge filter capacitors and massive transformers = a very stout power supply. I always remember seeing Lambda power supplies in the science labs whereas the engineering labs used HP power supplies. I just noticed that your work table for this video is a pinball game frame? Props to Lambda for giving you the user manual.

[noakeswalker]

You just don't see massive lumps of iron tx like that any more ! What a find - if you can find a bench strong enough to hold it up...

[baghdadiabdellatif]

Great work. I think the zener diodes you removed are good

[patim]

Very nice service from the manufacturer, very rare nowadays. Often they not even bother to answer.

[gordonwedman]

I bught a.nice Fluke 60 watt supply with LCD readouts but could not get it to work. Checked all the components and connections twice. Finally I read the operations manual carefully and discovered it would have no output if the rear panel sense jumper was not in place. Works great now😀

[rickhoffman]

Very informative video. Would you share the owners manual ?

[mybigtube]

Nice video. Both CR232 and CR274 were bad on mine also. How did you cross reference the part FMBZ104? I have a couple of other component that are bad such as a FMBZ107. Can you point me in a direction to a cross reference for the Lambda parts? They are SO hard to find.

Thanks!!

[michaudpierre]

Hello, Is the service manual for this LK 351-FM covers also the LK 352-FM ? if so, I am quite interested by this manual. Best regards

[christophS]

Nice repair. I would have loved to see the device work. Specifically, how do you control both voltage and current independently? Obviously you can't for a resistive load. Do you toggle between voltage or current supply? I guess I have lived in the digital domain for too long...

[FireballXL]

I was surprised you did not connect the sense wires as the diagram on the back shows how to connect them. Yes you are very safety minded worrying about capacitors being charged on a 40V PSU.

[Berre]

Arti, do you know that your channel reads: 'This channel has no content' when clicking on 'home'? Only when clicking on 'video's' does content appear. This seems to be different on other channels. No clue why.

[lesstime]

i have 4 of those, ,,1 is ok but 3 are dad, somebody cut some wires, know i"m stock because i have no idea where the wires going, without a schematic they are trash for me