Power Supply Problem

[ranchak]

I'm working on the regulated power supply from the GGG site. My problem is that I am not getting any AC on the output of the transformer. The transformer is getting hot. It's wired to 110v AC, I don't see how the wiring will work on this. Only one leg of 110AC is hot, the other side is a neutral. Or am I missing something?

[Barcode80]

sounds to me like your hot/cold wires are reversed.

[km-r]

check the secondary for continuity...

[grapefruit]

Proceed with caution. Electricity KILLS.

Disconnect mains! Make sure you have the 110V connected to the primary winding of the transformer. Disconnect the secondary of the transformer from the circuit. Power up the tranny and measure the secondary  with multimeter on ac volts. Stay away from the high voltage.

Be safe.

Cheers,
Stew.

[ranchak]

OK, I swapped the hot and cold leads and still only have 1.9v. Sometimes the simpliest things are the most difficult! On the spec sheet is says to tie 1&3 and 2&4. Apply power to 1 and 2. No problem that's what we have on the GGG layout. For the secondary hookup it says to series wire to get 12.6v. We do that by tying 6&7. Now the question is: Are 5 and 8 the outputs on the secondary side? If so the PCB is incorrect. 5&8 are tied with 6 and 7 being the outputs.

[grapefruit]

OK, I have no idea what transformer you are using, but from what you are saying it sounds like you have a dual winding primary and you're winding it in parallel because you have a 110V supply...

As I said before, disconnect the secondary windings and see what you get. If that doesn't work don't tie anything together on the secondary and see what voltage you get on each winding. If you have the secondary windings out of phase you won't get much output. If you give me the pinout data of the tranny and a link to the circuit I could tell you how to hook up the secondary.

I TAKE NO RESPONSIBILITY FOR YOU KILLING YOURSELF. DO THIS AT YOUR OWN RISK!

Cheers,
Stew.

[ranchak]

Hey grapefruit, here is the link to the GGG site:

http://generalguitargadgets.com/index.php?option=content&task=view&id=192&Itemid=217

I don't have the tech sheet on the tranny with me, this is the same tranny that smallbear sells only it a Magnetek brand. I did find this:

http://rocky.digikey.com/WebLib/Parallax%20Pwr%20Comp(Magnetek)/Web%20Data/FP12-200.PDF

Thanks, Ron

[grapefruit]

Ok, It looks like the tranny you are using is the correct one for that circuit. The windings come out in different places to what I'm used to. For f*cks sake have you tried checking the ac output of the windings with nothing connected. At least then you'll know if you have the tranny is operating properly and you can work from there. I don't mean to sound mean but I said this from the beginning. Check this is ok and we can go from there. Are you using the tonepad PCB? You may have a problem with the BR. Did you use discrete diodes?

If the transformer is getting hot it's because something is pulling a lot of current, and this will drag down the output of the transformer. Not necessarily because the transformer is wired incorrectly. DISCONNECT THE REST OF THE CIRCUIT FROM THE TRANSFORMER SECONDARY and see what ac voltage you get..

Again, do this at your own risk.

Stew.

[ranchak]

Stew, I disconnected the secondaries like you said. I tied 5&7 and 6&8. I have 8.7v between 5 and 6, and also between 7 and 8. The only thing is I should be getting about 12.6v.

[grapefruit]

Join the two secondary teminals together that are joined on the PCB and you should get 2 X 8.7V on the other teminals. If this is ok. Measre the resistance of where the tranny secondaries go without the tranny inserted to make sure there's not a short. Check the diodes are in correct position.

Stew.

[ranchak]

Stew, I tried various combinations hooking up this transformer, I still can not get above 8.xx volts. I did have an instance where the output voltage would continue to climb steadily, I shut things down after I got to 16 volts. The tranny was getting hot. What I'm looking to do is run one of these fltapack trannies to power an EH toroidal tranny for some tube projects that I want to work on. I need to have 10.0v to power the toroidal tranny. I'm a bit stumped at this point. Any help anyone could lend would be appreciated.

[smallbearelec]

Please check out my article on the Small Wart 200 for the correct connections to the transformer:

http://www.smallbearelec.com/Projects/SmWart2/SmallWart2.htm

The layout drawing has been vetted by a number of builders and is reliable. With pin 5 connected to pin 8 and nothing else connected to the secondary, you should see 18 volts or so AC between pins 6 and 7.

[ranchak]

Thanks Steve, I will give this a try.