I don't do any major adjustments until I have had a few rounds of thorough cleaning and oiling. I have twice had a 201 with a needle scraping against the turning part under the hook and race. In both cases it turned out to be oil and grime behind the groove in the needle bar causing to push the needle off position. I have had similar things with sticky swing arms, and hard packed, felted up dust in connection with feed dogs and bobbin cases. Timing issuse happens now and then, but they are not the most common reason for problems with upper and and lower thread not interlocking as they should. I hope your new machines cleans up easily, foot controllers included.