[Boatanchors] Collins 516F-2 solid state conversion, use unused 5V windings to buck AC to primary

[Bill Cromwell]

Hi Jim,

When I have replace the vacuum power rectifiers with diodes the 5U4, etc 
is completely removed form the HV supply circuits and so is the 5 volt 
winding. Been there. Done that. Reused the 5 volt winding for *other*, 
lesser, low voltage purposes.

73,

Bill  KU8H


On 01/07/2015 11:48 PM, Jim Wiley wrote:
> Keep in mind that in this case, the 5-volt windings were intended to 
> power the 5U4 / 5R4 heaters, which when operating are at several 
> hundred volts DC.  In fact, the DC voltage at this point is much 
> higher than the 120-volt primary winding.  using the 5-volt rectifier 
> heater windings as a "buck" connection should be perfectly safe.
>
> That may not be the case with other windings, such as the 6.3 / 12.6 
> volt windings intended to power tube heaters.
>
> Look at the specs for a transformer that was intended to power 
> something like a vacuum-tube TV receiver or a vacuum-tube audio 
> amplifier.  Those transformers had 1500-volt class insulation for the 
> 5-volt windings.
>
> - Jim, KL7CC