Orban 418A calibration/release module

Hey kids, just wondering if anyone has ever managed to dig up any info on the release module used in the 418A (I see a few threads that go nowhere on it around the web and not much else, and no response from Orban about it)?

I've got one here that has had a half hearted restoration by someone (they recapped it but clearly didn't clean up the residue, meaning I had to clean up a tonne of corrosion damage) and it just doesn't react right. Threshold seems way off, but it doesn't calibrate as per the service manual (trim control does nothing at all to GR meter in that step, and doesn't seem to affect GR when feeding signal) so I'm suspecting the release module ain't right.

Anyone got any more info on these?

Thanks!

Well then, this isn't looking promising, haha

Alternate plan... anybody got a working unit they could take a measurement or two on?