5E3 power transformer wiring leads color help (Missing Data Sheet)

[Mojojtm]

Hey All,

I bought a kit, this is my 4th build, 1x 5F1 2x 18 Watts, so I have basic experience in electronics also build many pedals.

However the power transformer that the kit came with, has no data sheet. There is some broad explanation on the PT itself as there is a label on it.

The PT model is Model PW-5E3 but can't find anything about it on the internet.

I made a photo, could you help me to isolate the wiring with each color = to function that the lead should accomplish There is primary and secondary but I can't figure it out, I have ideas but I am afraid of making mistakes and burn everything out.

I bought the kit from HK China as it is basically the same as many other kits sold here in the Netherlands.

The current volts here is 220, I am following the Mojotone kit manual instructions, therefore I was trying to match the Mojotone PT wiring colors but that do not match obviously so I am stuck

Any help very much appreciated.

[martin manning]

Here's what I get from the label. Looks like all of the primary leads are coming from one side and all the secondaries from the other. Do some continuity checks to separate the wires by winding.

[ViperDoc]

Take another stare at your transformer label.

[Mojojtm]

Here's what I get from the label. Looks like all of the primary leads are coming from one side and all the secondaries from the other. Do some continuity checks to separate the wires by winding.

Thank you so much for your kind reply, and it is already a lot more clear but I am having some doubts on reporting this in practical terms or to better say how to actually do it.

Here is the manual photo:

[Mojojtm]

In other words since the color are repeated I am not sure which one is which

Which are the 2 HV Secondary, these carry Voltages those are connected to the rectifier tube in the manual are red in my PT are Green but there are 3 Greens

Which one are the 6.3 tube filament? in the manual are Green in my PT is also green but how I distinguish from the other 2 Green? Anyways to do it without measuring?

Which one is ground? In the manual is red/yellow

Which one are the 5v rectifier filaments in the manual are yellow?

[martin manning]

You are going to have to separate the leads for each winding by checking for continuity, or measuring resistance. For example, all the leads on the high voltage secondary will have some finite resistance between them, and infinite resistance to leads on any other winding.

[Mojojtm]

You are going to have to separate the leads for each winding by checking for continuity, or measuring resistance. For example, all the leads on the high voltage secondary will have some finite resistance between them, and infinite resistance to leads on any other winding.

Ok got it! I think I understood all. I will call again if needed hopefully is resolved

[Mojojtm]

You are going to have to separate the leads for each winding by checking for continuity, or measuring resistance. For example, all the leads on the high voltage secondary will have some finite resistance between them, and infinite resistance to leads on any other winding.

So if I measure for continuity for example between the 2 green high voltages, since I have 3 green only the one with continuity are the one to be used on the 340v high voltage therefore the other green 6.3v will be excluded? Correct?

I know is silly and of course I have no much experience, it is because I usually buy kit that drives you step by step with same leads color and therefore never really learned anything time to change and learn something out.

[martin manning]

...since I have 3 green only the one with continuity are the one to be used on the 340v high voltage therefore the other green 6.3v will be excluded? Correct?

Correct.

I know is silly and of course I have no much experience, it is because I usually buy kit that drives you step by step with same leads color and therefore never really learned anything :-( time to change and learn something out.

Yep!

[Mojojtm]

You are going to have to separate the leads for each winding by checking for continuity, or measuring resistance. For example, all the leads on the high voltage secondary will have some finite resistance between them, and infinite resistance to leads on any other winding.

Ok got it! I think I understood all. I will call again if needed hopefully is resolved

Hey Martin
Thanks I was able to twist the leads following your advise so Green with Green that match Red Red on the Mojotone Kit, that had continuity with high resistance, Yellow Yellow which match Green Green, White Black which match Yellow Yellow

The same on the other side (Primary) there was easy as the colors are unique Yellow Black which match White Black.

There is only one wire left that I am stuck with, on the secondary the Black leadwhich match Red/Yel is the ground, or it is grounded according to the Mojotone manual instructions.

However there are 2 blacks left, which one is it, how can I see it is the one matching Red/Yel?

[sluckey]

However there are 2 blacks left, which one is it, how can I see it is the one matching Red/Yel?

Connect one ohm meter probe to a green wire, Touch a black wire with the other probe. The one that shows resistance reading is the one to use as the red/yellow wire.

But it really doesn't matter because you will connect ***BOTH*** of the black wires to chassis ground.

[martin manning]

However there are 2 blacks left, which one is it, how can I see it is the one matching Red/Yel?

The same basic principle applies: There are four separate windings, one primary, and three secondary, and there is no DC path between them. Identify the three black wires by finding the secondary wires they have continuity with.

As Steve says, you can ground the black wire that has continuity with the yellow wires (the heater center tap) at the same place as you ground the black wire that has continuity with the high voltage leads (the HV center tap). If you use that heater center tap, you don't need the 2x 100 ohm resistors that Fender often used to create a ground reference. I see in the layout snip you posted that neither a heater CT nor the 2x 100 ohm resistors is shown, but Mojo's current layout shows the 2x 100 ohm at the pilot lamp. I'm guessing that is showing a partially completed state. https://www.mojotone.com/Amp_Kits/Tweed ... 5E3_WD.pdf

If you want to verify your conclusions, connect a low voltage AC source to energize the transformer and measure the voltages on the leads you intend to use. The easiest way would be to use a 12 VAC adapter connected to the 120V primary leads, where you could then look for about 1/10 of the expected AC voltage on the secondary leads.

[Mojojtm]

However there are 2 blacks left, which one is it, how can I see it is the one matching Red/Yel?

Connect one ohm meter probe to a green wire, Touch a black wire with the other probe. The one that shows resistance reading is the one to use as the red/yellow wire.

But it really doesn't matter because you will connect ***BOTH*** of the black wires to chassis ground.

Great that worked perfectly, all clear now. So both Blacks go to ground, may I cut all the other remain leads short and isolate the with some heat shrink tubing?

[martin manning]

You can ground the black heater center tap, but you don't have to. See my post above.

I would clip any exposed conductors and bundle the unused leads out of the way for now.

[Mojojtm]

You can ground the black heater center tap, but you don't have to. See my post above.

I would clip any exposed conductors and bundle the unused leads out of the way for now.

Yes the concept of (the heater center tap) is clear for both (the heater center tap) and (the HV center tap) basically if I ground both I can spare the 2x 100Ohms because ground will compensate.

Question

What happens if I still keep on the 2x 100Ohms on the pilot light, will that compromise anything or will that have a neutral effect.

I am asking to understand the logical beyond this. So in my understanding I can still put the 100Ohms and that will still be fine, correct?