Hewlett Packard 3336B replacement control board

[Wazza]

Hi all,
 
I'm attempting to repair a hp3336b and have found it has a replacement control board (03325-66516) fitted.
 
This is not documented in any of the service manuals I can find, but is referred to in 'service note 3325-A21' or the service manual change sheets for the 3325 generator (the 3325 generator can also use this replacement control board).
 
Does anyone have information on this newer control board?
 
Regards,
 
Waz

[m k]

90003 manual has 526 board.
Maybe you can gain something by comparing previous and next.
At least you can say what are still like they used to be.