macphail

Hi

Is there a schematic for early/late CCUs? Specifically, something to give me an idea which of IC9 to IC12 controls the left mixing flap motor? I've just replaced the motor but from what I've read elsewhere (Johns 964 site) the associated opamp (Siemens TCA2465) blows.

Thanks,

Andy

mojorizing

Hi Andy,
Firstly, check if you have DC voltage +/- at the servo plug when actuating the servo.
I have that info at home, but I'm not home for awhile, I have the schematic of the connects to the CCU, and knowing that you can trace to the proper IC that drives that particular servo. I'll report back tonight what pins connect to that servo. Also, I have a few of those Siemens TCA3465 available, they're not cheap at $32 a piece though.

mojorizing

The left mixing servo is connected to K5 and K18, "K" being the 25 pin connector on the CCU.

macphail

Thanks for the info - I'll see if I can identify the failed opamp. I managed to find four of the Siemens TCA2465 in Hong Kong but they're not here yet.