Lamda EWS1500-12 SMPS fault

[muddasirwaheedmalik]

Hi every one.

My post/query/request is two parts:-

I got my hands on a couple of cheap but absolutely working Lambda EWS1500-12 supplies. Very cheap from a old bulk store. I got one absolutely working condition.

1500 Watts, 12 Volt out put , 125 AMPS... for less than 100 USD.

I hooked it up with my Car power amplifiers...2xFocal 2.150 to drive 400 w into 4 ohm, tested it with 40 HZ sine wave for full 15 minutes....The supply didnot sweat a bit. the output voltage was set at 13.5 V and it merely dropeed to 13.42 V. Then used for normal HT/,music for couple of days. no issues.

Out of sheer bad luck i just replaced the old fansx2. well the new ones had m,etyal pin with lock inside.....and when i fixed it not realizing the metal pin it shorted the secondary rectifier heatsink with one of other thick terminals . Now the power supply does start...voltages jumps up and down but i hear Whiz , twiz twiz from the primary switching heat sink,,, it heats up too much instantly and gives burning smell.... the power up LED stays lit, the fans are working and nothing else is heating up...only the heat sink with probably two diodes and 2x4 FETS just start giving burning smell within seconds...5-8 sec. i then just turned it off.


So my question is what could be the apparent fault. i shorted the secondrary and the primary is switiching is heating up. the seoncondary is cold as cucumber. TRIED A LOT but could not get cirucuit diagram. openint that thing is almost a nightmare.. would have to desolder at least 2 dozen devices before ican put test probes on the primary heat sink.


Second question: 24 volt version are also available. CAN i take mod rout and put +/- 24 volt on 12 V car amplifer secondary power rails... would then eliminate Switcing in CAR AMPS and reduce current level requeirements probably by 1/4.


PS. i have these Focal Car amps which are superb in SQ and are not used in my car. so the reason for its usage in home. And linear power supply...welll 125 A will require a huge tranformer, space, cost and capacitance. please advice.


Can someone refer link to find schematics or how to trouble shoot the power supply.


Regards

[muddasirwaheedmalik]

any one please???

[johansen]

no, you can't just pipe 24 volts into a 12v car amp and expect it not to blow up.

I have two lambda 1500 watt supplies that i gave up on, they were 5v 300 amp units and they died because i turned them on after they had been left in an uncontrolled high humidity environment for 6 months.
so, i think yours is toast. also, had you just shorted out the secondary you would have been fine, it probably would have melted whatever metal is on the fans, instead it sounds like you shorted something on the primary side to the secondary.
you will need to replace the fets, and the fet drivers to be safe, which are probably ir2011's