I have been reading about people who have the Red Dragon Scale AND a ring of protection. When I try that with Minsc, I am told that it cannot be equipped due to other items that I am wearing.
Minsc has on:
Red Dragon Scale
Baldur's Helm
Boots of Avoidance
Cloak of the Shield
Ring of Fire Resistance
Amulet of 5% Magic Resistance
Gauntlets of Archery
(no shield)
Do you see any reason that he should not be able to equip the ring? I did take each item off individually and tried the ring. Only when I remove the Red Dragon Scale could I equip the ring.
Do you have ToB yet? Because the Red Dragon Scale was considered non-magical in SoA - meaning you can wear magical stuff with it, ei. the Ring of Protection. This was fixed in ToB, making the armour magical, so you cannot equip any other magical items.
I'm sure it works in SoA, I have Keldorn equipped with Dragon Plate + Ring+2 since ages
BUT I heard that it could have been modified in ToB... so let's verify it the other way : strip your Minsc of everything, put the armor, then the ring, let's see if it works !
I've found that if you have the Red Dragon Plate and the ring of protection all ready equipped when you start TOB, you can keep the combination. However, if you take off the ring or the armor, you cannot put them both back on again. I went thru TOB with Keldorn wearing both. However, I had to reload one time because Keldorn died and when I resurrected him, he couldn't equip the Plate and ring again. I hope this helps.