here's a very special microcassette recorder. š§µ
in case you haven't seen these before, the cassettes are a lot smaller than a standard audio cassette.
let's have a look inside.
umm š¬
since these are alkaline batteries, you can neutralize the leakage with vinegar.
wow these batteries really leaked a lot
how cute. now to check for battery damage
not looking good
it's spread throughout the flex circuit š¬
soaking the battery contacts
oh no, these electrolytic capacitors have also leaked š¤¦āāļø
to neutralize that we have to use a base, such as sodium bicarbonate
I'm gonna have to remove the whole flex circuit
removed, and I've started scraping away at the corrosion in the lower left. the copper is pretty thick so it all seems to be intact
the mechanism is quite compact. there's a drive belt in there but it seems to be intact
so why is this very special? it's a rather ordinary microcassette recorder from probably around the late 1970s.
except this was the first gadget i ever laid my hands on--this particular one. apparently i was a baby and my dad thought it would be funny to hand it to me to play with, and he said i got so excited i started shaking š
anyway the corrosion comes right off with a fiberglass pen
new caps soldered in. I had to add some wire to jumper a broken via.
whew, finally got it all recapped.
so it actually works fine now (mostly, there's some motor rumble coming out of the speakers i need to figure out)
and the tape has recordings of family members on it, stuff from 25 years ago. amazing.
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i printed a new panel insert that has two BNC sockets on it (the original probes would have had captive cables)
the tricky part is that this oscilloscope has a 333K ohm input impedance instead of 1M like umm every other scope on the planet. fortunately someone designed a little conversion circuit...
in honor of Sim Wong Hoo, here's a quick historical review of the Sound Blaster! š§µ
but first we have to go back to their first sound card, the Creative Music System from 1987. (image credit: Bratgoul on Wikipedia)
this card has some special "CMS-301" chips. if you peel back the sticker, they have had their top marks removed. they're actually SAA1099 synthesizer chips made by Philips. Creative wrote music composition software for musicians on the PC.