Hacker News Reader

Old car dash instruments are often upgraded the same way. They use new parts to drive the original indicators so it all looks correct, but is actually accurate.

There are even kits to replace the guts of old car radios with modern stereos while preserving the controls and dials and their function.

View on HN

Speaking of cars, I know I've heard of people who restore old tube-based car radios replacing the "buzzer" (or whatever it's called) that boosts the battery voltage up to the "B" voltage (I think that's right) with something more "modern" (probably a 555 oscillator and some other parts); the metal can for the original part is more than roomy enough for the replacement, and the new stuff is more reliable.

"Buzzer" = Electromechanical Vibrator

https://en.wikipedia.org/wiki/Vibrator_(electronic)

On my '72 Dodge, there's a mechanical device to lower the 12 volt system voltage to 5 volts for the dash instruments. It's a buzzer kind of thingy. Some people replaced it with a modern voltage regulator to get exactly 5 clean volts, and found that the instruments didn't work right.

It turns out that the instruments needed the erratic 5 volts, else they'd "stick".

Reply on news.ycombinator.com