The aux in barrel measures the correct outside diameter of 5.5, however the length is about 1.1 mm. But comparing the Radio Shack M barrel, this power supply barrel is less than 1/32" shorter.
It fits snugly into the TIU and the unit label pn is PSA36-180 (PA). AC INPUT 100-240V~0.5. Output DC 18V _ ...2.0A.
2 1/2" wide, 4 1/4" high and 1" thick.
mokemike