advice on Clementine build

[Shannon Parks]

Those resistances are bad, Kirk. Are the yellows and whites connected to anything (i.e. not to the PCB)?

Shannon

[TomMcNally]

Kirk -

Yes, for 120 volt operation it's red-red and black-black. The tricky thing would be for 240 volts *which* red and black to use, just like the secondary. They need to be phased properly. Antek hasn't done us any favors using the same colors on each winding. There is no simple way to for the average person with a multimeter to figure it out.

Are you saying your transformer comes up with proper voltage readings AFTER the smoke?
Something is odd here ...

[fiftyfivefilms]

Those resistances are bad, Kirk. Are the yellows and whites connected to anything (i.e. not to the PCB)?

Shannon

No the yellow/white wires are floating free from the board...

Kirk -

Yes, for 120 volt operation it's red-red and black-black. The tricky thing would be for 240 volts *which* red and black to use, just like the secondary. They need to be phased properly. Antek hasn't done us any favors using the same colors on each winding. There is no simple way to for the average person with a multimeter to figure it out.

Are you saying your transformer comes up with proper voltage readings AFTER the smoke?
Something is odd here ...

and yes Tom it is odd about the color coding of the wires, it would be so much easier had they coded each wire. Yes I get 330V across both pairs Yellow/White at full voltage. The smoke was minimal, just a little puff at the CL-90 @ 20V...then I shut it down...

Looks like a Dynaco is in my future!
Cheers,

Kirk

[TomMcNally]

I don't think the transformer is bad then. I think if you join the proper yellow and white in series and ground the center point, you'll be OK. You may have shorted a winding when you brought it up before. Yes, the color coding is poor. Edcor does the same thing with the filament windings on their XPWR-005, but it's easier and safe to figure out 6.3 volts than 660 !

Again, if you join (tap quickly) yellow from one and white from another, and measure, you should get twice the voltage of one winding. If you do it wrong, you'll get half. I did it with a limited current low voltage supply to for safety.

It's worth trying again. Make sure the filament supply isn't shorted also. Mine had wire colors that differed from the sheet.



It looks like blue/red and green/orange

[fiftyfivefilms]

I don't think the transformer is bad then. I think if you join the proper yellow and white in series and ground the center point, you'll be OK. You may have shorted a winding when you brought it up before. Yes, the color coding is poor. Edcor does the same thing with the filament windings on their XPWR-005, but it's easier and safe to figure out 6.3 volts than 660 !

Again, if you join (tap quickly) yellow from one and white from another, and measure, you should get twice the voltage of one winding. If you do it wrong, you'll get half. I did it with a limited current low voltage supply to for safety.

It's worth trying again. Make sure the filament supply isn't shorted also. Mine had wire colors that differed from the sheet.



It looks like blue/red and green/orange

Tom,
I'll try that..question, do you ground the "twisted pair" during testing? I was thinking of using a jumper to briefly combine the "twisted pair"
Just to reconfirm, visualize a capitol "E" the center of the "E" is the twisted pair, the top is the white and the bottom the yellow, you test at the top and bottom and are looking for the combination with the highest voltage.
I'm thinking 10v from my Variac should be sufficient.
My filament wires were correctly coded no worries there.

Thanks again

Kirk

[TomMcNally]

Kirk -

You are correct, basically the diagram from Antek, just need to figure out the wires.

I would not use the Variac, because you have basically unlimited current (until the fuse blows)
look around and see if you can find a small AC (not DC) wall wart of 6 to 9 volts. Remember that
the output voltage will be pretty high with a lot of current (dangerous) with more than a few volts.

Don't ground anything, or even have it connected to the amp. Just my suggestions, you can make it work
a number of ways. But seriously ... only SECONDS each try. Don't cook it. Hook the voltmeter up to
a set of white and yellow, apply AC, TAP the other pair while observing the meter. Go for the highest
voltage. When you're happy with the results, hook it up and SLOWLY bring it up.

Keep in mind that your meltdown before (assuming the transformer is still good) could have been an
issue with the filament windings, if they are shorted you'd have the same smoke.

[fiftyfivefilms]

Kirk -

You are correct, basically the diagram from Antek, just need to figure out the wires.

I would not use the Variac, because you have basically unlimited current (until the fuse blows)
look around and see if you can find a small AC (not DC) wall wart of 6 to 9 volts. Remember that
the output voltage will be pretty high with a lot of current (dangerous) with more than a few volts.

Don't ground anything, or even have it connected to the amp. Just my suggestions, you can make it work
a number of ways. But seriously ... only SECONDS each try. Don't cook it. Hook the voltmeter up to
a set of white and yellow, apply AC, TAP the other pair while observing the meter. Go for the highest
voltage. When you're happy with the results, hook it up and SLOWLY bring it up.

Keep in mind that your meltdown before (assuming the transformer is still good) could have been an
issue with the filament windings, if they are shorted you'd have the same smoke.

Hi Tom, Well I ran out to Goodwill for a wall wart(open!) I got a 7.5v AC...I hooked it up and I'm getting 22V between both pairs of the Yellow/White wires but once I tap the other two together the voltage drops to zero! this happens with all combinations...
hmmmm?

[TomMcNally]

That doesn't make much sense, unless the transformer is shorted internally.



Shorting white to yellow of a hot winding isn't good, we're looking for the center ones.

There aren't that many combinations!

I'm out of ideas. Are the gray leads taped off individually and safely out of the way?

[miker]

What happens if you tie the two yellow secondary leads together and measure the voltage between the two whites? Or, tie the two whites together and measure across the two yellows?

Nothing to loose at this point.

[fiftyfivefilms]

Yup, the grey leads are taped off... I'm out of ideas also. ..I think now I need to decide if I should get another Antek, this is the one they recommended ( they responded to my query after they had mailed me the one I have now!)
https://www.antekinc.com/details.php?p=656
...if I do that I'm wondering if I could re-use the cover for the smaller transformer?....or if I should just get the recommended Dynaco...

Anyway thanks for all your help...

What happens if you tie the two yellow secondary leads together and measure the voltage between the two whites? Or, tie the two whites together and measure across the two yellows?

Nothing to loose at this point.

tried that and got 0.37v across the two and no change once I tied the other two together...OYE!!!

[TomMcNally]

The AS-05T320 only has one HV winding with no centertap. You could use it if you added two more diodes to make a bridge I suppose. I used the AS-1T300 which works fine.

Maybe you could send yours back to Antek in a flat rate USPS box and ask THEM to test it and mark the leads. It could be miswired.

[fiftyfivefilms]

The AS-05T320 only has one HV winding with no centertap. You could use it if you added two more diodes to make a bridge I suppose. I used the AS-1T300 which works fine.

Maybe you could send yours back to Antek in a flat rate USPS box and ask THEM to test it and mark the leads. It could be miswired.

thanks Tom,...sending it back might not be a bad idea, my dealing with them have been all over the map..first I ordered and paid for AS-1T300!...days later they got back to me that it was out of stock....I ruminated about an option and even asked them for a recommendation citing the Dynaco's parameters,...no word so I ordered the AS-4T320, days after receiving the transformer they finally got back to me with their recommendation, the AS-05T320! Oye!... anyway thanks again.

On a positive note I've built several of Shannons designs...most with out incident, this was a problem of my own creation.
Cheers,
Kirk

[fiftyfivefilms]

Just one final thought: I contacted Antek this morning and talked to the technical guy...he has a heavy accent so it was a little difficult to understand him, however he did let me know that the order of the wires as they physically come out of the transformer is the same as the schematic diagram!...that would have made everything so simple!!! I re-tested with my wall wart using that knowledge and got the same result, 22v and when I briefly connected the center two it drops to 8V...when I reversed the pairs it was the same.

Antek said to mail it back to them, but I don't know how I could expect a refund as it's probable I caused this from my impulsive behavior..

Cheers,
Kirk