The Melles Griot model 05-LPM-942-065 will operate most 11 to 15 inch long HeNe tubes or heads.
These are new units and have European standard wire color code.

Specifications:

Input Voltage: 115 / 230 VAC ±10%, 50 to 400 Hz.
Output Voltage: 1850 to 2450 VDC.
Output Current:  5.5 to 7 mA, preset at 6.5 mA.
Trigger Voltage: >10 KV
Input Leads: 3.5 inches, 22 AWG. Flying.
Output Leads: Alden high voltage connector
Dimensions: 4.3 x 3.0 x 1.2 inches (109 x 76 x 31 mm)
Mounting holes: 2.3 and 2.5 inch center spacing.

Features:

4 second Turn-on delay (defeat by cutting violet wire loop)
Alden high voltage output connector.
Output current adjustable with onboard trimpot
RoHS compliant.