SL-1200 DC Power Supply DIY

[Frankyc2003]

Where do you position the "Bleeder" resistor you mention on the caps, as it is not on your very good picture of the Capacitor assembly or the schematic?

Ken, the bleeder resistor is connected between postive pole of 3rd cap and negative pole of 2nd cap.

Hope this clarifies.

[6L6]

Ken, the bleeder resistor is connected between postive pole of 3rd cap and negative pole of second cap.

It's not even that critical - As long as it's downstream of the bridge, connected from + to GND, you are fine. It's main purpose is to discharge the caps once the power is turned off.

[Frankyc2003]

You can actually see it in action when switching off. The strobe light dies slowly instead of being immediatly switched off.

[Frankyc2003]

Jim, any chance you could elaborate on how to make/wire the rectifier section?

Here is a bridge rectifier neatly laid out using 1N4007s



and here is the schematic

Only omission on the schematic is the little film cap across.

[6L6]

You can actually see it in action when switching off. The strobe light dies slowly instead of being immediately switched off.

That's more of a function of the new capacitors holding so much more energy than the stock cap. The old cap is a 470uF, the new cap bank is (3) 4700uF, for a total of 30 times more capacity. It takes a wee bit to suck them dry, where the old one is discharged very quickly.

[Qwin]

Thanks for the clarification chaps.

Francois it was the orientation of the diodes I needed in relation to the input and output conections.

Is your example parts build layed out exactly as the diagram below it? In other words the inputs/output locations are the same?

You guys presume some knowledge which I don't have.

I mixed up the .1uf film cap with the 1k resistor in the photos. Doh!

After a bit of Googling I now know that the Bar the arrow points at in the diode symbol represents the end with the silver stripe on the part, I'm picking it up, slooowly. LOL.

[6L6]

Is your example parts build layed out exactly as the diagram below it? In other words the inputs/output locations are the same?

More than willing to help.

But that last sentence needs clarification.

Also, have you ever de-soldered anything? It's significantly harder to remove than insert. Removing the stock bridge and snubbers has the potential of bodging up the PCB and making for an expensive repair... But you could always re-use the stock diode bridge in the new PSU.

[Frankyc2003]

Yes exactly as laid out in the diagram.
Flip my pic and you have exactly the same as in diagram.
You then connect your AC at both top and bottom of the diamond.
Your DC is connected left and right of the diamond shape.
Always double check your DC polarity against the diode orientation before applying any voltage...

[Qwin]

Yep I can solder de solder like a pro - Just don't know what all the bits do

It was like I thought, the diagram and parts do not match, you have to rotate the photo of the parts to get the same orientation as the schematic. That dictates which corners the inputs/outputs are connected to - all is now clear, thanks for the patience.

[Frankyc2003]

As recommended by Jim, always try the circuit before you hack the rectifier from the pcb.
Get the transformer out. Wire its primary to an iec plug for mains supply and then using aligator clips or terminal block, wire your rectifier to the secondary windings. Test its output with your multimeter. You should get a stable DC reading.