I made a little CRT computer thing.

[ThetaReactor]

Album: https://imgur.com/a/uNDcnkK

Thought you gents would enjoy this sort of thing. I've mostly used it as a PICO-8 console, but I wanna tweak it a bit to better utilize the keypad and be an info terminal. To-do list, calendar, that sort of thing. Like one of those old Chumby things, but full of phosphors.

[OochyKoochy]

Thanks for that. Interesting seeing re appropriated old tech.

[(o)(o)]

Album: https://imgur.com/a/uNDcnkK

Thought you gents would enjoy this sort of thing. I've mostly used it as a PICO-8 console, but I wanna tweak it a bit to better utilize the keypad and be an info terminal. To-do list, calendar, that sort of thing. Like one of those old Chumby things, but full of phosphors.

Nice grinder there haha

Great job! Love it..



Although sprayed green.. the text looks blue... maybe it's just me.

I'm no electrician so curious.. do you approach circuit boards of this vintage with caution? Bulging caps seems commonplace for one thing.

I've got a circa 2002 Primare amp that I've been considering sending for re-capping and service for some time. It's powered 24/7.

Trouble is it's in use every day so I've been putting it off!

[Dio]

The rule of thumb in the retro computing community is not to fix things that aren't broken. Collateral damage when things go wrong is not that common. There are exceptions, like the PSU X-caps in the BBC Micro or the transistors in the Spectrum DC-DC circuitry. Other than that, inspect carefully and don't touch it if it works.

[ThetaReactor]

Yeah, you can see a bulging cap if you look through the rest of the images.

I might replace it. It may improve the picture quality. But it's not a priority. I'm not too worried about breaking anything, either, as the TV is a no-name 2004 model I spent $4 on. It's essentially worthless. The only caution I exercised was staying away from the rear end of the tube while playing with it. I doubt there's enough juice to do serious damage but there's definitely enough to hurt.

The text looks greener in person. It's a bad photo. Once I get the interface tidied up and the notification LED configured, I'll get some better photos. I've got a second little TV to play with, too, so I might do another. That one's got tuning knobs on both sides, maybe it would be a good Pong box.

[venusian]

That's very nifty and good use of the battery compartment.

It's a shame the CHIP board failed. I bought one of their £50 'pocket' systems and whist the keyboard is utterly awful and the touchscreen is almost unusable the whole system works surprisingly well.

[Dio]

You're right that the early 2000s is the nadir of capacitor quality though.

If they're bulging they are usually well out of spec. When my Behringer mixer went unreliable I pulled it apart and replaced a couple of clearly past it capacitors in the PSU to get it working again. I'd tend to replace anything that looked like that on principle, it's only a few minutes work.

[Misfit]

Great job.

I really had no idea you could fix/fill/repaint old plastic shells of stuff.

What kind of prep/paint did you use to get such a good finish?

[skab]

The only caution I exercised was staying away from the rear end of the tube while playing with it. I doubt there's enough juice to do serious damage but there's definitely enough to hurt.

That's what I did when I was fiddling around with CRTs, too, but isn't the high voltage only on the anode under that suction cup? The heater and the rest at the tip end of a CRT shouldn't carry any high voltage, right?

[ThetaReactor]

it's only a few minutes work.

If you have the replacement, yeah. I might have something appropriate on a junk board somewhere, but currently it's on the "next time I'm ordering components" list.

Great job.

I really had no idea you could fix/fill/repaint old plastic shells of stuff.

What kind of prep/paint did you use to get such a good finish?

It's not a very good finish. As for prep, I scuffed it up with a scotch-brite pad, shot it with some high-fill primer, sanded, sprayed paint, sanded some more, sprayed some more, finished with a matte clear. Krylon does a 2-in-1 primer/paint that works pretty well on plastic, but these colors were part of their "camo" collection and are just regular acrylic. There's actually a shade difference between the front and back halves of the shell because they've got different numbers of coats. I plan to attack it with some weathering effects, so a dodgy finish isn't a big deal.

For the filling/shaping, I used a two-part epoxy for the structural bits. The syringe style stuff works well for small jobs like this. I've used some rip and knead epoxy putty before, too, but it can be tricky to get the ratios quite right or else it doesn't cure properly. I used automotive glazing putty for the skim coat to get it smooth.

[ThetaReactor]

The only caution I exercised was staying away from the rear end of the tube while playing with it. I doubt there's enough juice to do serious damage but there's definitely enough to hurt.

That's what I did when I was fiddling around with CRTs, too, but isn't the high voltage only on the anode under that suction cup? The heater and the rest at the tip end of a CRT shouldn't carry any high voltage, right?

I know enough to know that I'm a rank amateur. While I have a good grasp of the theoretical operation of a CRT, I'm no technician. Between the caps and the flyback circuit, I just assume anything connected to the driver board is dangerous.

So yes, you're probably right, but you're not testing the theory with my fingers.