David J Brooks wrote: > I asked how they test for this, and part of what i remember is that he > described it as hooking up the test unit for a car to see what codes > are showing.
Well, that's step one. A company producing something like DSLRs would typically engineer a "socket" onto the circuit boards somewhere. When the right equipment is attached to that "socket", it can talk directly to the circuitry on the board, ask the board to self-diagnose, and maybe even perform tests that the in-camera circuitry can't. That's typically step one of any Problem Determination Process (PDP) for advanced or complex digital gear that has(a) processor(s) on board. For checking optical alignment, they're likely to use a device called a collimator. For a house like Pentax, there would typically be at least two rigs: one for camera bodies and one for lenses. The purpose is the same, but the hardware is different. The basic idea of an optical collimator is to send a beam of light of known characteristics across a "gap" to a receiver. The receiver can interpret the received beam of light in terms useful to the diagnostic procedure (there are different types for different purposes). In grossly simplified form, to use the collimator, you set up the rig with the equipment under test in the "gap" and compare the characteristics of the received signal to the transmitted signal's characteristics. I used to use laser collimators to align digital (paper) scanners, back in the day. On those units, the sender was a precision engineered unit that positioned a laser very precisely above the scanner's platen. In this scenario, the scanner's sensor is the receiver. Put the sender in configuration "A", position the scanner's mirror at "X", and only the leftmost "K" pixels should be showing a reading, the max amplitude should be "M", and the standard deviation of the amplitude falloff should be "S". Repeat at a dozen or two dozen locations on the platen, if everything is aligned. With those few measurements you could diagnose and correct nearly any alignment defect between the platen, sensor, and stationary and moving mirror assemblies, if the engineers put the right adjustment hardware in all the right places. > I'm not having much faith now, i don't trust those code readers at garages.:-) Well, they're reporting the system's self-diagnosis. Sometimes that's like asking a psychopath if he's crazy ... you're asking a defective instrument to measure itself and report back. That's obviously "fraught with peril". :-) -- Thanks, DougF (KG4LMZ) -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
