222/Repairs

222PS hybrid RC probe tip assembly repair

Bob Miller says:

I thought others might be interested in repair of the 222PS hybrid RC probe tip assembly if it has been damaged. The attached screenshots show an emulation using stacked 1206 SMD components that meet the rather challenging distributed RC circuit accuracy and ability to (probably) withstand the maximum applied voltage spec of the P850 probe while fitting in the available space. The replacement composite assembly fits comfortably in a piece of 4mm OD Teflon tube inserted into the probe body. The inset in the second screenshot shows the 222PS top trace of a non-damaged P850 probe with the emulated probe shown in the trace below.

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  Schematic

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  Simulation results

CRT socket issue

See 224/Repairs.