Repair of smps SOUNDCRAFT PSM300 HELP needed

[MicrosiM]

I will do a video and upload. The second time I tried the SMPS without the bulb the relay started switching so had to power down. I Think I may have trouble doing the video without the bulb but as I have a second set of mosfets I will try it. I am wondering is the auto ranger causing the problem as I have all voltages at the outputs with the bulb.

Thanks for the reply i will upload video in the morning

Use 400W Bulb, and try again, it seems that your supply is working, but I am not 100% sure.

 

[Resonant]

In normal operation with bulb as you switch on, the auto ranger would switch to 120V and bulb lights up brightly only for a couple of seconds (maybe even just 1,5s). Then switching back to 220V and bulb should be without light.
If auto ranger started switching fast check for shorts on mosfets before trying again. With me it was a sign that they just died

But if they are ok and you have voltage at output I have no idea whats going on with the noise on the fan.

If you only use 220V you could disconnect auto ranger if it causes problems

 

[a1rstudios]

Hi I made a typo last night I should have said the relay started clicking on the Auto ranger very erratic without the bulb connected so i pulled the power to save it. All voltages are present on the outputs. This is what the original problem was. I have tried it with the bulbs again and it has correct output voltages video uploaded. I dont have a 400w i am using the 2 in parallel
[video=youtube_share;oIoMlV-8zEs]http://youtu.be/oIoMlV-8zEs[/video]

 

[a1rstudios]

Sorry for the double post trying to deleate. Resonant when power up with bulb the relay clicks after about a second and the lights stay dim the video is showing them a bit brighter then they are but they are still on. without the bulb first time there was a ticking noise about 50hz then second time i tried without bulb i got the relay clicking erratic. Mosfets and 2 large blue Caps next to transformer are new. I am going to remove that resistor in the autoranger as you did. The verticel control board next to the transformer would that have any influence

 

[a1rstudios]

Just an update I Think its Fixed. As Resonant Did I Removed the Resistor for the Autoranger and when i powered up Bulbs stayed off, So I removed the Bulbs and it starts fan at full speed 3 LED's and all correct voltages at the output connector.

Just hope The console is ok but i will connect up now see how it goes

Thanks for all you help guys I wish i could buy you both a Drink

 

[a1rstudios]

I have checked it connected to the Soundcraft Ghost console works but i have noticed that i have no 48v phantom power when the console cable is connected to the smps (48v LED on when not connected). I can manage without phantom power as i use dynamic and valve mics with supplys, But i did not notice this before so maybe this has been like this for a while. Maybe it s an easy fix?

 

[MicrosiM]

I have checked it connected to the Soundcraft Ghost console works but i have noticed that i have no 48v phantom power when the console cable is connected to the smps (48v LED on when not connected). I can manage without phantom power as i use dynamic and valve mics with supplys, But i did not notice this before so maybe this has been like this for a while. Maybe it s an easy fix?

did you check the cable? the fuse?

 

[Resonant]

something must be pulling down your 48V in the console.

I don't know what its like in the console, but 48V usually doesn't have much to
Maybe just a couple of diodes for protection, caps for filtering noise and resistors for current limiting on each channel.

 

[a1rstudios]

Is it ok to use the console like this as i do not want to go digging around the console. A lot of work disconnecting the looms and turning upside down to remove bottom cover. Just dont want the cause any more damage to psu using it this way

something must be pulling down your 48V in the console.

I don't know what its like in the console, but 48V usually doesn't have much to
Maybe just a couple of diodes for protection, caps for filtering noise and resistors for current limiting on each channel.

 

[a1rstudios]

Update:
I have just nearly fried the SMPS I Disconnected the cable from the console to check it (MicroSim was right) when i powered on the SMPS i had 48v light but as i moved the plug on the end of the cable i heard some strange noise's from the supply and got a burning smell so i killed the PSU. I opened up the plug on the console end of cable and the white wire's (+17v) insulation was bare and must have been touching Earth. This is all i can find with the cable but i suspect i will have to re solder both connectors on each end, It still does not solve the 48v but i will check cable further.