Can I replaced an attached power cord?

You can go about it two different ways. Cut out an opening for an IEC jack or put in another captive PC.

I've done both styles & they took about the same amount of work, as I had to enlarge the opening for a bigger strain relief when going to a bigger captive. With this particular captive, I also had to enlarge the holes in the circuit board, so the first thing you should do is take off the cover & see what's involved.

The benefit of the IEC jack is you can experiment w/other PC's.

As for cost, it all depends on if it's worth it to you.

In my examples, I spent about $50.00 making a DIY 83802 & installing an IEC jack on a relatively inexpensive DVD player; about $20.00 ea. (x2) for a Volex & strain relief to replace the captive PC on some older mono-blocks.

On a personal note, it wouldn't bother me if I saw something advertised for sale & it had one of those adapter boxes on it but that prob. means the item would sell for less than a similar item w/o the mod. Something to consider if you ever decide to sell, unless it's already at the bottom of its price potential.