[TenTec] 9420 Problem

[Ken Brown]

Hi Chris,

The 9420 has five transformers. Four are for the  4 high current 12 VDC 
linear mode (not switching mode) regulated power supplies, and the fifth 
transformer is for a regulated supply that runs the control circuitry in 
the 9420. The primaries of all five transformers plug into the 81419 
Power Supply Controller Board, as does the secondary of just T5. There 
are also four or five other connectors on that board for current and 
voltage monitoring of the four high current supplies. The primary power 
to the four transformers is switched by relays on the 81419 board. The 
relays are controlled by the circuitry that monitors the current and 
voltage of the four supplies.

The outputs of the four supplies are not paralleled together. They run 
separately all the way to the four PA modules in the Hercules II. The 
manual shows the four PA modules DC supplies paralleled together ONLY in 
the battery power cable, NOT inside the Hercules. Since you have been 
running on battery power, maybe someone made a modification paralleling 
the supplies inside the Hercules instead of only outside in the power 
cable. This might mess up the 9420 current monitoring.

The first thing to check is all of those connectors on the 81419 board. 
Also there is jumpering on that board to select 120/240 VAC mains 
voltage. That should be checked too.

If it turns out that you need to replace the 81419 board, contact me. I 
have a spare.

Ken N6KB

Christian von Wechmar wrote:
>
> Anyway, the 9420 does not work. 
>