I got the manual.
The whole tip assembly including the ac/dc switch is one part number with no breakdown.
Just another note-when I took the probe apart , there was a loose transistor floating around inside.
I think what happened is someone dropped the probe, breaking off the one tip and bending the other and knocking one of the transistors out of its socket. Then they found the probe didnt work, so they put it on Ebay. All the transistors are socketed.