Tektronix's Haphazard Component Reference Numbering?

[Chris56000]

. . .Can anyone suggest why Tektronix, right back to the thermionic valve era, have always haphazardly numbered components on their circuit diagrams?

. . .As an example, the A1 Vertical Preamp PCB in the 465B Oscilloscope starts resistors at R1015 and finishes at R1974 with none of the circuit sections in groups, e.g. CH1 dual FET input could start at "1001", the next circuit section at "1050", etc., but they've not even done that, and the obvious suggestion that springs to mind of beginning "CH2" reference numbers "1200" isn't followed either!

. . .All the components throughout their gear for which service manuals quoting component references have been published are numbered like this, and taking the A1 Vertical Preamp Board in the 465B as an example again, there's probably something like 150 resistors and 15 preset–pots on it (I've not counted them exactly!) but they've used approx. 165 unique references out of a stretch occupying 958 individual references for resistors and presets!

Chris Williams

[Warsp]

This is just based on observation, but from what I can tell at least based on the 465B manual is that the reference numbers are based on assembly and board location. The first digit of the designator appears to be the assembly number. The second digit is the components y-position on the pcb diagram and increases as you go down the board, and the third digit is the components x-position on the board and increases as you go across the board. The fourth digit is likely there to differentiate between components that are close together.

[Chris56000]

. . .Member Warsp, thanks for that!

. . .I don't usually pay close attention to the physical placement of components on a manufactured board, and it never twigged to me that Tek's numbering was derived from the physical location of the components on the board!

. . .What matters to me that if a layout diagram is provided, then I'd rather like the gear I'm actually looking at to actually bear some resemblance to the layout and the circuit diagram, that's all!

Chris Williams