The best description of the 8662/8663 power supply deficiencies that I¡¯ve seen is this YouTube video:?. ?The original power supply design is really, really poor and a ticking time bomb to expensive repairs, especially as the instrument both ages and accumulates run time. ?There are two particularly notorious axial electrolytics that in order for the instrument to operate, must pass on a 50% duty cycle over 1 ampere at a potential over 200 volts. ?The original caps are under spec¡¯d and there was a revision by HP to increase their value. ?The best practice retrofit is to increase the capacitance value further, raise the voltage rating considerably and select a cap that has a much lower ESR value and lifetime rating. ?Watch the video - the poster understands the issue and does a good job explaining it. ?I recently bought a 8663 and beefed up the supply so that this issue won¡¯t occur (again). ?Every one I¡¯ve seen had evidence of repair in the primary side of that disaster that passes for a switching supply.
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On Feb 19, 2023, at 5:26 PM, colingoode2000 via groups.io <colingoode2000@...> wrote:
?Is there a definitive document that details about the mods to the A2 boards and which ones should be present Also is the 8662a serial number in software available on the device?
