Most, if not all, of our new scanning densitometers use a different power supply than they used to. The new power adapter is a switching AC adapter that can be used for either 110 or 220 volts AC. Since there is a crossover point for some models, the way that we distinguish between them is that we add a "U" to the model number for those units using the new power supply, i.e. 391U as opposed to 391 (all 390s are 390U). Ask the customer to look at the bottom of their unit. The model and serial number are both on the same little silver sticker, (at least the newer serial numbers).
If there is a "U" as part of the model number, then they will need this part number: SE30-177 (power supply) and SD33-07 (line cord); they might need both if they misplaced their line cord.
Older 391 units used power adapter, part number SE30-61. HOWEVER, X-RITE can no longer obtain this part and conversion to the "Universal" model is necessary. You would need an additional conversion adaptor SE108-95-01 Along with the SE30-177 & SD33-07.
The "U" didn't appear right away on the instrument after the change so this doesn't always apply so you may want to inspect the input jack on the instrument.
If there is some uncertainty, have the customer look at the power input jack on their densitometer. If the jack is simply a hole, then they need the old style adapter which has a bayonet style plug: SE30-61(convert to "U"). If the jack has a pin in the middle of it, then they have a "U" style which has a barrel style plug: SE30-177.