Darn mis labeled PT

[Tom Phillips]

I have seen subject issue and the incorrect color coded OT wiring that Chuck H and gi mentioned PLUS "Center taps" that were far off from center PLUS line power cords that had the green wire connected to the hot blade. I've also found several replacement Fender dual foot switches with the reverb and tremolo wires reversed. Now I do my own verification measurements before using the mentioned parts and many others.
Basically skip the "Trust" and proceed directly to "Verify."

[The Dude]

I don't recall ever seeing something like this. Imagine if this transformer was purchased/installed by a novice or someone doing their first build. It could take forever to figure out the problem.

I should clarify that statement. I've definitely seen different color transformer wires that don't match datasheets. What I haven't seen (to my recollection) is a winding that has a mislabeled CT. In other words, if you have a center tapped winding, it's normally assumed that the wire colored differently than the other 2 is the CT. Not in this case.

[Chuck H]

it's normally assumed that the wire colored differently than the other 2 is the CT. Not in this case.

'it's normally assumed that the wire colored differently than the other 2 is NOT the CT.'

Is this what you meant? I sort of I interpreted this.

[The Dude]

I meant, for example: You have 3 wires on a center-tapped winding. Presumably, 2 are the same color (outside winding) and the 3rd has a stripe/different color or some marking to denote that it is the CT. Maybe, for example, they are all green and one of them has a yellow stripe. So as, I said, the one colored differently is the CT............. NORMALLY! In Randall's case this was not so, and one of the plain green wires was the CT.

Although I've seen different color wires on transformers in the past that aren't typical or don't match a datasheet, I don't recall ever seeing what I would consider a mislabeled CT.

[Chuck H]

Although I've seen different color wires on transformers in the past that aren't typical or don't match a datasheet, I don't recall ever seeing what I would consider a mislabeled CT.

Same here. I haven't run across a misidentified CT. That's a pretty big error to place on the builder. I thought getting an OT with a secondary that had black and orange swapped was bad enough. But misidentified CT would be worse.

[Purgasound]

Happened to me when a client wanted to upgrade transformers in a JCM2000. We brought in Classic Tone transformers and the OT was fine but the PT had incorrect colored wires on the primary side. Whenever you hooked it up "correctly" it would pop the mains fuse. I chased my tail looking for other parts wrong in the amp until I ended up hooking up the PT "wrong" by mistake and the amp sprung to life. When I retraced my steps I knew something was up so I pulled the PT completely out and checked all the windings with a scope and low voltage on the Variac. Sure enough I found the color codes didn't match the spec sheet. I had put in dozens of Classic Tone transformers and never had a problem. Hopefully I'll never see that again, it was definitely not fun but figuring it out in the end was mentally rewarding.