In the 1970's I don't remember early voting, and it seemed like every school had voting machines

[frazzled]

31. I first voted on those lever machines too

But they were hardly the nostalgic dream machines we like to reminisce about. They could miscount, and were open to manipulation by election officials.

Lever machines are an amazing feat of industrial revolution technology, but unfortunately their mechanical nature is a huge flaw. Lever machines tally their votes on cascaded odometer wheels behind their back panels. A recent study found that 250 out of 800 lever machines had defective odometer counting mechanisms that would stick instead of turning over. Even when the devices are working properly, at the end of the day poll workers can misread the odometers. In the 2000 election in Boston, almost 20,000 votes were initially ignored because elections officials were confused about which odometer reading to include and tally. Although local voting law usually calls for more than one person to be present when the odometers are visible on the back of a voting machines, sloppy processes have been alleged to allow odometers to be misread or changed by unscrupulous officials.

https://static.scientificamerican.com/sciam/assets/media/pdf/selker.pdf

Lever voting machines offer excellent voter privacy, and the feel of a lever voting machine is immensely reassuring to voters! Unfortunately, they are immense machines, expensive to move and store, difficult to test, complex to maintain, and far from secure against vote fraud. Furthermore, a lever voting machine maintains no audit trail. With paper ballots, a it is possible to recount the votes if there is an allegation of fraud. With lever voting machines, there is nothing to recount!

In effect, lever voting machines were the "quick technological fix" for the problems of a century ago; they eliminated the problems people understood while they introduced new problems. Because they are expensive to test, complete tests are extremely rare. The mechanism is secure against tampering by the public, but a technician can easily fix a machine so that one voting position will never register more than some set number of votes, and this may not be detected for years.

In effect, with lever voting machines, you put your trust in the technicians who maintain the machines, and if you want to rig an election, all you need to do is buy the services of enough of these technicians. This is quite feasible for a metropolitan political machine.

https://homepage.divms.uiowa.edu/~jones/voting/congress.html