[R-390] re: Maintenance: mains voltage

[2002tii]

W. Li wrote:

>So am I correct in assuming that running our 390's at
>a heater voltage of 5.5VAC is not going to cause
>problems? Mine seems to operate well at that heater
>voltage. Seems to me ruuning that low will really
>prolong heater life based on earlier studies.

That is correct, you needn't worry about damage to the tubes by 
running them with the heaters 13% low.  I do not think you have to 
worry about a 390/URR or 390A dropping out of regulation at that 
voltage, either (approximately 105 line volts), but if drift gets 
worse than expected you may want to up the line voltage to 110 or so 
to get the regulator back into regulation.

Best regards,

Don