In reading all the posts and responses over the years about the 3D and serial numbers, I believe what had happened was, when Fisher - Los Banos was making the 3D's, there was a specific process to assemble and calibrate/test. All the 1021 serial numbers had that process applied. When the First Texas take over occurred, that original process still took place on some of the 1121 units ( whether they were made in Los Banos or not I don't know, but it seems reasonable to believe they were).
After the take over ( and I presume movement of the factory/assembly/testing process), the original way to calibrate/test did not occur and a new way was implemented (or some steps/procedures in the old way were not followed). The rest of the 1121 batch (and those moving forward with I assume newer serial numbers) had this new way applied and it was not up to par with the original way. As owners started getting these newer units and comparing them to older CZ's or the 1021 3D's, they were finding the depth was no where near where it should be.
Once this problem was indentified, it was corrected and all subsequent 3D's had the calibration/testing done the original way. So there may be a batch of 3D's that were made in the interim, that did not have the original way of calibration/testing done to them, hence them being sub-standard when compared to the older CZ's.
In all of this, I am not sure if the Los Banos CZ's had different components (ie, a different manufacturer, better quality, etc.) than the First Texas ones, and that also added to the issue. I think it was more of how the unit was put together, calibrated and tested but if anyone can add to this, please do so.
Bottom line is, I think this whole thing has been put to rest. I think when guys are selling their 3D's, they state the serial number and where it was made, to inform the buyer that it is an up to spec 3D.
An up to spec 3D is an awesome unit, be it a Fisher Los Banos or First Texas unit.
