06-05-2011, 09:07 AM
Mark, you may find the regulator voltage settings to be false unless under load. To prevent any inadvertent damage to those delicate 1.4V filaments, I suggest you use the 'dummy load' idea across the LT output to roughly set the voltage and determine the sense of the the preset adjuster, i.e. which way turns the voltage up and which way down. Then before connecting to a set proper, I'd reset to a level below 1 volt. Switch on and monitor the voltage output whilst setting to as close to 1.4V as possible. That way you minmise the risk of damage. You could consider replacing the variable with a fixed resistor (read the pot's 1.4V set value).
I'm sure you will find the HT level will rise to somewhere close to 90V under normal operating conditions. Anywhere above 80V will be fine. The average all-dry portable shouldn't draw more than 12-20mA HT.
Hope this helps.
-Tony
I'm sure you will find the HT level will rise to somewhere close to 90V under normal operating conditions. Anywhere above 80V will be fine. The average all-dry portable shouldn't draw more than 12-20mA HT.
Hope this helps.
-Tony
