I have an old blue steel case model #6150 M* transformer. The transformer looks great and works fine. Unfortunately, the original power cord's insulation sheath is degrading to the point where I'm uncomfortable using it. Can an average guy w/ an average mechanical and electrical skill set replace the cord, or does it have to be repaired at an Authorized Marklin Dealer?
Would anyone who has(successfully)done this please explain it to me?
Thank you

This is very dangerous. There is great danger of fire or electrocution. Don't use the transformer as it is.

My old transformer started getting this problem years ago and I rewired it with a good modern flex. Take it to a competent electrician.

Hi 48,
I won't comment on your specific problem but I wanted to post a couple cents worth of general observations for the 'average guy w/ an average mechanical and electrical skill set'. When soldering electrical components be sure and use an electrical solder as most nonelectrical solders and flux are acid based which will cause corrosion related problems. Also look at some web photos of a properly soldered joint vs a poorly soldered one. Secondly, one needs to make certain that any replacement AC cord is wired up identical to the original. Accidently miswiring the hot, neutral, and ground wires on the device can be very hazardous. In the USA, hot is the small flat prong, neutral is the larger flat prong, and safety ground is the round prong on a common household 3 wire cord. One needs to determine which is going where before replacing the original wire. If you're not in the US, then disregard the above as it's always going to be something different.

If the above isn't absolutely clear then I would definately have someone qualified work on it or buy a new device.
-George