New tranny bigger than old: does not fit the chassis hole!

[slidincharlie (Carlo P)]

I have gotten a Weber power transformer from Ted Weber for my '77 SF Deluxe Reverb. The old one had gone south (see my thread below), and Ted sent immediately a new one as warranty replacement.
Model: W025130EU (export version for EU mains voltage).

TROUBLE: the new tranny has a top bell a little larger than the old one (which was the same identical model), and it does not fit the chassis hole. It's 4 mm larger and 1 mm longer.
May I replace the new top bell with the old (smaller) one?
I have never opened a tranny, and don't know it this operation is safe.

NOTE: the new replacement is also higher (that is with more "layers") and a little heavier than the old one.

P.S.: I have already posted this topic in the Weber forum and emailed Ted directly, but am in desperate need of a fast reply, thus I am posting also here...

[Mars Amp Repair]

hello Carlo,
You could do that, but I think I'd want to know that the xformer he sent is really the replacement for your old one electrically. you could go through all that trouble & find there was an error in what was sent to you.

I'd vote on the caution side & wait for an answer from the source. glen

[slidincharlie (Carlo P)]

Glen,
I've had a correspondence with Ted Weber last night.
He never answered clearly why the new tranny looks different from the old one (BTW, the new tranny is as high as the stock US tranny). Nonetheless he told me that I can mount the new tranny without its top bell.
I tried to put the old bell on the new tranny to no avail: the two trannies are built differently under the hood, and there is no room for wires if I put the old bell on the new tranny.
Anyway the stamp on the bottom bell is the right one.
But... there is a differentnissue now, and I'm starting another thread here

[Alex R]

If the bolt holes match, maybe you can take the bell off, put the txfr in the hole from under the chassis, then refit the bell from above inside the chassis, then put the bolts in. Or yeah do without the bell & lose a bit of screening that often doesn't matter anyway. Loads of amps don't have bells inside the chassis.

[slidincharlie (Carlo P)]

Ok Alex, thanks for the suggestion.

[Tom Phillips]

I like the suggestion Alex made.
Concerning the end bell size difference there is a disclaimer on the Weber Transformer page ( https://taweber.powweb.com/store/magnetic.htm ) that there may be a fit problem. Too bad they are not all built with the smaller end bell. Then they would fit in both versions of the chassis.

It's nice that Weber posts a spec sheet. Many replacement suppliers do not publish one at all. However, it would be nice if the spec sheet included the dimensions of the end bell. Obviously, the design changed recently. A common problem when going with the low bidder supplier solution.

Overall you sure have been handed a lot of trouble because of this transformer since this is the third problem since you got he first one.

Tom

[sadgod]

I have a bassman 135 I had to cut into for a hammond o.t. I think manufacturers try to accommodate the more "prestigious" amps before the sf's. If you cant find a better fit at a decent price. At least you will feel good knowing you did whatever it takes to bring a good amp back to life.