Couple of things:
I replaced one of the BNC connectors on my TDS210 a couple of weeks ago. It was a very do-able job job, I had to remove the top shield in order to get access to the solder joints for the bottom shield which I had to remove in order to get enough room to desolder the joints on the BNC connector - although if I had a finer tipped desoldering iron (I have a Hakko 808) I might not have had to bother but it was reasonably straight forward to replace.
It is s slightly odd ball BNC connector, made by TE Connectivity / AMP - I used part no 6274127-1 as it was available from Element 14/Farnell
Mine has had the mod (well it was sent back for it, and has a sticker saying it was carried out at least - is that being cynical?), and the Ground wire runs from the back of the mains connector across to a spade lug on the 'main board' the same is that one, and I would be surprised if the Australian Defence Force had not sent theirs back to be modified (they tend to be very fussy about such things).
Did exactly the same with one I scored some years back.
It was a common breakage, those BNC mounting pins. Even replacements break the pins.
Remedy: scrub some of the conformal coating off the adjacent GND plane on the top side of the PCB and strap the BNC's down with a strip of thin copper sheet soldered to GND plane and BNC's. Quick work with a big tip and hot iron required. They don't come loose again.
With care it can even look quite neat.
Also had a failed backlight inverter in mine. Confirmed with the bright torch test.
IIRC it was a 0.33 uF cap that set the frequency for the primary switching transistors for the 1150 V backlight inverter. Cap had drifted to a value in the pF region.
30 c fix.
This unit had around 600 power cycles in its log.
Did some research on the "earthing" issue and my PCB was a SN after the recall, so Tek must have revised the PCB. All that stuff used to be on the Tek website, not sure now.
Had a look through my files and all I have now is the Users and Service manuals in PDF if anybody needs them.