Marshall vintage transformer originality- how to verify...?

[Guitarjb]

I own a Marshall ‘72 Super Bass (model 1992) which has been converted to late-‘60s Plexi-era Super Lead specs.

I have owned the amp for almost 11 years; it was sold to me as having all-original transformers and choke, and I have never had any reason to question that fact. I see no evidence whatsoever of either if transformer or the choke ever having been replaced or otherwise tampered with. In fact, there is still red dye on the bolts holding the transformers to the chassis (the ones not obscured by the circuit board).

However...now that I am considering selling or trading the amp, a prospective buyer is asking questions about verifying that the transformer and choke are all original. He explained that he had a friend who is knowledable about vintage Marshall amps examine the photos I provided, but here are no ink-stamped codes on either transformer or the choke- so the friend wasn't able to verify anything, which scared the buyer away.

I have seen countless photos of vintage Marshall Super Bass and Super Lead amps in which the transformers and choke look EXACTLY like mine, also without numbers stamped or any other identifying marks/stamps. I have also seen a very small number of amps which DO have a stamped code on at least one of the transformers; this appears to be much more rare than amps with no stamped codes.

Here are links to the photos...

These were shot a few months before the POINV was installed

https://flickr.com/photos/39963395@N08/ ... 3871567802

Detail of PPIMV wiring:
https://flickr.com/photos/39963395@N08/ ... 7961061714

For reference, to view other amps similar to mine:
http://www.amparchives.com/folder/668/

For prospective buyers, and so I am NOT misrepresenting the amp, how can I verify either way whether the transformers and choke are in fact all original?

-Joe

[Guitarjb]

Anyone...??

[Tazin]

The transformers and choke look original to me.

[charveldan]

Transformers are stock.

SGR' [grid resistors] have been changed.

Filter caps are replaced which is good.

Looks like a toggle switch was replaced at some point.

I have have a Tech install new bias filters & a 3 prong cord [if its 2].

Other than that very complete set of pics, dont worry about scared off buyers, plenty of buyers for that amp.

[Guitarjb]

Guys- thank you for your input on this. I think the potential buyer was either being overly cautious and his friend doesn’t know vintage Marshalls as well as he might think, or he was just saying that because he changed his mind.

Either way, no big deal. And thank you all again.

-Joe

[Guitarjb]

Transformers are stock.

SGR' [grid resistors] have been changed.

Filter caps are replaced which is good.

Looks like a toggle switch was replaced at some point.

I have have a Tech install new bias filters & a 3 prong cord [if its 2].

Other than that very complete set of pics, dont worry about scared off buyers, plenty of buyers for that amp.

It does have a 3-prong AC cord, and the bias filters were replaced about 8-10 years ago (all filter caps were replaced at that same time). Considering this, do you still think it’s time to replace the bias filters, or perhaps even all filter caps?

Joe

[charveldan]

Just the bias filters if they're original, they're electrolytic, a failure there will cause runaway bias voltage & could take out the output transformer.

Replace those with {2} Sprauge 10 uf 150 volt caps. Should be an easy fix with a competent Tech.