Wireing the Gyraf Pultec

[Hulk]

I just finished my Gyraf Pultec but when I powered it up nothing happened - totally dead :?

I suspect I did wire up the two power trafo's the wrong way (Amveco 62062 and Triad FS12-1000) here is how I wired them up:

And here is how I connected them to Gustavs PCB

Isn't that wired correctly?????

 

[gyraf]

Measure your voltages - AC and DC.

Take care..! High voltages..!

Jakob E.

 

[Hulk]

hmm no matter how I measure the Amveco toroid I get 41V on all the sec. no matter how I connect them together (I have unsoldered the wires from the PCB so they do not touch anything!) - no load should only be around 14.2V???

 

[Guest]

Looking at your amveco drawing I think you have an error. For 230V the black and red wires should go together and the input AC should be on the yellow and violet wires.

 

[Hulk]

Hi Thomas

Thanks for your reply but I don't understand??

I did connect PRI for 230V: red-black and yellow-violet like on the drawing - I'm really getting some strange values when I measure - could the Amveco toroid be defective??

 

[Guest]

The torroid could be dab, yes, but let's see if your wiring is OK first. Red/black together at center so both primary windings are in series. AC input comes in, one wire to yellow, one wire to voilet. Is that right?

Since you have your transformer unsoldered, now CAREFULLY measure the voltage on each secondary. What do you get? Hopefully somewhere around 16-18VAC for a 12VAC wilding unloaded.

 

[Hulk]

Hi Thomas

I have pri black+red connected together and one yellow and one violet to AC 230V but when I measure each of the unsoldered sec. they all 4 show 41-42VAC :shock: (measuring one sec. at a time)

 

[gyraf]

Measuring with reference to what? You need to measure across each winding - otherwize it dosen't make sense. You find what wire pairs goes to what windings with an Ohmmeter.

 

[Hulk]

I did measure across each winding and I used the star grounding in the chassis as reference :?

But how do I measure the voltage and resistense correctly??

 

[Guest]

Just to make sure, measuring AC volta with one meter lead on the green and one on the red secondary you get 41VAC? and likewise with one meter lead on the brown and one lead on the blue secondary wire you get 41VAC? Don't use the star ground for reference in this measurement.

Measure both transformers and see what you get. It is possible, but unlikely, that your transformers are bad. You can check for winding resistance (should be a very low, like a couple of ohms or less).

 

[Hulk]

Hi Thomas

Thanks for your reply!!

I have just measured the sec. the way you described (red-green measure and brown-blue measure) and then I get no VAC reading at all :shock: but againg if I use star ground as reference I get 41VAC on all 4 sec.

This is strange stuff....

 

[gyraf]

you can't use the star ground for that..

 

[Guest]

OK, you get no output on the secondary of your Amveco. Did you also try your Triad?

You can check the windings of your transformer for an open with your meter set to resistance. Be sure to unhook all the wires from power before measuring. Measure all your wiring and let us know what you get. Be patient. If I can't answer right away, someone else surely will.

 

[Hulk]

I'll be patient :grin: and thanks for your help!

Ok I measured resistense on the Amveco secondaries without any power connected and I got 1.5 Ohm between red-green and 1.5 Ohm between blue-brown - no other combination gave any reading on the meter!

 

[Guest]

OK, secondaries seem alright. Did you measure your primary windings as well? They should give you simolar low readings across the windings. If they measure OK go to the next step:

Since you get nothing out we need to make sure you have the right voltage comming in. This is 230VAC so be careful. Measure the input voltage and let us know what you have.

 

[Hulk]

Ok I measured the resistense on the primary wires:

yellow-black 53.4 Ohm and red-violet 53.4 Ohm so they seem ok too right??

 

[Hulk]

ahmm I just found out that the 315mA fuse had blown so the sec. show around 14 VAC now :green:

Thank you for your help

 

[Hulk]

hmm the saga continues :?

Now it seems to work (have not send audio through the unit yet) the tube lights up but there's a faint hum coming from the Triad trafo (sound like the faint hum coming from my Engl tube amp) is this normal??

When I measure the pri. on the triad i get 285VAC and on the sec. I get 10.5VAC (measuring directly at the pins on the Triad trafo) is this ok??

 

[Hulk]

More trouble...

I get 440VDC on the 3K3 2W fuse :shock: When I power off the unit the voltage immediately falls to 325VDC and then the voltage slowly starts to count down :?:

 

[Hulk]

Ok It seems like I have solved all my problems - I had wired the triad trafo sec. in parallel and it should be wired in series - so all voltages are perfect now :green:

Thanks for your help Thomas!! :thumb: