Transformer ID

[C Moore]

I have what looks like a Fender PT.
There are three sets of numbers on the cover. The last set is hard to read. But to the best of my ability.....

010020
csa test
60 (might be 606) 3071 7

Anyway....when I put 120 VAC to the two black leads (actually one Black and one Black-Green).
I do not get anything out of the 2x Green, or the 2x Red, or the 2x Yellow. If i go from a Red to the Red-Black or Yellow to Yellow Black I get some low voltage readings. Cannot remember exactly, but in the 15-25 Volt range.
Is there a website that kind of explains these color codes.? Is it possible I have a 240 Volt transformer.?
Thank You

[Cliff Schecht]

What you have is definitely a power transformer. Red-something-Red is always HV, green-green is 6.3V and yellow-yellow is 5V. Take an Ohm meter to the primary and see if you get a low resistance reading (usually ~2 Ohms), it might be blown.

[C Moore]

Hey Cliff -
Unfortunately, that is exactly what I have....a blown PT. Primary reads OL on my meter. Over Load, Open, more than the meter can measure. The 5 and 6 volt windings are right under One Ohm. The HV winding is about 500 Ohms.
Is a blown PT pretty much a paper weight, or is there something that can be done with them.?
Thank You

[Cliff Schecht]

You can have them rewound but it'll probably cost as much as a new transformer to do so.

[diagrammatiks]

hey you can see the fender color tags here

http://www.el34world.com/Transformers/fentrans.htm

looks like it could be either of these [img:187:176]http://www.el34world.com/Transformers/images/041316.gif[/img]
[img:225:176]http://www.el34world.com/Transformers/i ... 2798_C.gif[/img]

but double check that link since it looks like you have no black or white primaries...

geofex has a number of out of circuit tests you can do on the transformer as well.

http://geofex.com/ampdbug/pwrtrans.htm

[C Moore]

Hoffman has some great info on his sight......I always forget that. Thanks for reminding me. Though, I do not see my exact color scheme. The primary is Black and Black-Green for starters. So I am still not exactly sure what amp this came from
At any rate, its life is over. I will try and wait for a used PT to pop up.
Thanks For The Help

[billyz]

Some Fender PT have a fuse internally on the primary. Like in a red knob twin or showman. It is a real bitch to get at. You need to unsolder the copper shield and peel back a layer to see it. I just leave it out and reconnect the leads. It is even harder to resolder the copper shield.

[C Moore]

Some Fender PT have a fuse internally on the primary. Like in a red knob twin or showman. It is a real bitch to get at. You need to unsolder the copper shield and peel back a layer to see it. I just leave it out and reconnect the leads. It is even harder to resolder the copper shield.

Wow, that's crazy...!!!!!
First I have ever heard of this. The PT I have is on the smaller side.....like for a Deluxe Reverb perhaps.
Thanks

[billyz]

I have not seen a deluxe transformer with the fuse though. But it might be worth a look.

[Phil_S]

Blown PT...here's your chance to take one apart and see what actually goes into it. Then you can sell the split off lams on eBay along with the bobbin, and you'll get $10-20 them on a good day.

This is a project that takes patience. I suggest it is good for a cold winter day with bad weather blowing. First, take a bit of sandpaper to the outside of the lams to remove some of the varnish. Remove the end bells. and bolts. Find the locking shim and gently remove it (you'll need to pull hard or work it up with a screw driver, but try not to bend it. Then you take a razor knife and slice between the first and second lam layer to split off the first one. Remove without bending. Stack in order and orientation using the bolts -- if made properly, the lams stacking has considered grain orientation that should be maintained. Do it again and again until you have it apart. It will take you a few hours. Sometimes a blow with a mallet on the razor knife is needed.

It is also something you can do for 5-10 minutes a day until it's done.

Once you remove the lams, you can unwind the bobbin (LOL, it's a mess of fine wire after you remove roughly 20 turns of fat filament winding. If you get lucky, you might see the short and be able to repair it, but don't count on that. Besides, putting it all back is harder than taking it apart, and it can be an environmentally dirty job!

[C Moore]

Hey Phil -
That is interesting stuff. I may do as you describe, and take it apart, but I would never put it back together.
I have a teacher that was an "Electrician" at The Mare Island Ship Yard. He did all kinds of cool jobs, including motor rewinding. That is a process most guys NEVER get to experience. And you are correct, the varnishing and baking process of doing these kind of jobs is a filthy mess.
But I should do what you suggested, and maybe document it with pictures. You can guide me through the process if you feel like it.
My teacher would be proud of me for tearing it apart as you describe.
I will be in touch.
Thank You

[rdjones]

The PT I have is on the smaller side.....like for a Deluxe Reverb perhaps. Thanks

I think 010020 is the international version of the Champ/Princeton PT.
Does it have 2"x2.5" mounting centers ?
These should have a series/parallel primary.
If only one primary is bad you may still be able to use it at 120V, at a reduced draw.

rd