Thanks Doug. This is when i miss having Dad around. He would have given me an answer like yours.:-)
Dave On Mon, Mar 24, 2008 at 6:45 PM, Doug Franklin <[EMAIL PROTECTED]> wrote: > 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. > -- Equine Photography www.caughtinmotion.com http://brooksinthecountry.blogspot.com/ Ontario Canada -- 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.
