This is something I've had for years and was keeping in case I ever need it for a repair - which no doubt I will if I sell it
- but in the current circumstances I'm going to put it up for sale. Someone else may have a more pressing need...
An original Radiospares (RS) 'Heavy Duty' power transformer, exactly as used in the earliest Marshall JTM45s. This one didn't come out of a Marshall - in fact I can't remember exactly what it did come out of, possibly some old lab equipment I used to work with in a former job. It's open-frame at both ends so you will need a bell cover to make it right for a JTM45, but if you're replacing a blown one that won't be a problem. It's not exactly in pristine condition - there's quite a lot of rust on the plates and the label is badly torn and only just adhering to the winding, but it is the correct label with all the tap information listed (apart from a couple of missing ones which you can work out).
I have proof-tested it at 253V - the maximum permissible UK voltage - and there are no shorts or other problems, it draws 36mA of primary current at that, and all the secondary voltages are present and correct (with no load). Beyond that, I can't guarantee it - it's older than I am and was in use for probably half that time!
I have no real idea what it's worth, but this one appears to have sold on reverb for somewhere in the region of £600 - https://reverb.com/au/item/19670010-1960-s-n-o-s-radiospares-r-s-rs-mains-power-transformer-jtm45-marshall-guitar-amplifier-part
- so based on the poorer condition I'll say £400 for mine, including postage.
"Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski
"Just because I don't care, doesn't mean I don't understand." - Homer Simpson