kyle @Pegasus@mastodon.social

ACAB includes troops

a knife!

the other thing this results in is that the video ground point is at 5.5V too, but the audio input ground still needs to be 0V. a ground loop isolator on the audio input cured it - trying the same isolator on the video side trashes the signal. coils are weird i guess.

TV in question is a dutch market Philips X24T681. judging from the date codes on the exploded safety caps i had to replace, it was made somewhere in late 1969 or 1970.

it has an uh, "unusual" design where the composite video coming from the radio section is biased by a chain of three dropper resistors that create a 5.5V supply for the rest of the set to use.

in practical terms this means any video signal you put in needs to be amplified somewhat, at the moment i'm using a headphone amplifier

this does need an isolation transformer though as these old valve TVs are AC/DC and have a internal ground potential of 230V.

if you connected without having the TV on an isolation transformer it would short circuit and destroy both the tv and whatever you plugged in

analog tv is very degraded by the multiple steps of conversion involved in broadcasting and reception. since analog tv broadcasts end, vintage TVs have been stuck without a signal source except for very cheap and shitty RF modulator boxes

by removing the TV tuner, radio frequency amplifiers, and radio to signal converters, i can feed the video and audio sections a direct signal from any composite or S-Video device and get the highest picture quality the tube could ever display

someone just bought me a 350VA isolation transformer so that i can safely jeep signals into a 1960s valve tv. life is really cool sometimes

electrolytic capacitors normally have a tolerance of +/- 20%.

the good side is you don't have to use an exact replacement.

the downside is that i want it to be tidier than that

destroy personnel