Catch-all cheap hardware alert thread

This may help… may not be the same model but at least will give a general idea of what’s involved.

Actually that’s definitely a different model. The AliExpress page shows an LA7806, that’ll be your starting point for modifying the H/V deflection circuits.

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I’m hoping I’ll be able to just swap the wires on the yoke for the outputs of a cheap, off-the-shelf chip amp like I did with the one I’m working on now, and not even bother to touch the board.

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I’ve grabbed a couple too, will be interested to compare notes and/or see how you get on!

While I was making breakfast this morning I sort of formulated a master plan.

If I can get the idea of modifying Ian Holzer’s PD vector synthesis libraries to use composite video luma as the Z signal, and run it successfully on a Raspberry Pi (the Github doc implies that video capture, at least, hasn’t been confirmed to work on the Pi) and these CRTs are easily modifiable for simple X-Y operation and work halfway decently, I could make a kind of low rent, briefcase size Rutt-Etra/Scanimate style system:

Raspberry Pi #1 with a small touchscreen, Hifiberry, Nanokontrol and capture dongle running the modified Puredata patches → modified Watchman → Raspberry Pi #2 with a RPi High Quality Camera mounted to capture the CRT and Andrei’s Chromatic Abberation for colorizing. Plus switchable direct inputs and outputs for each stage so it could be used with other stuff (i.e. a better display and camera).

Other than a case the only part I don’t already have is the Pi camera, touchscreen and an amp board for modding the CRT when it shows up, and I could do proof-of-concept without having the colorizer section at all. I’ve got two other things to finish first but it should be a good mid-late summer project and I’ll start messing with the Puredata library in the mean time.

Maybe mini-Wobbulator in the fall, I think I already have a color yoke that will work for it but the little TV set I’m using as a platform is tightly packed enough that I’d probably have to replace all of the wiring to actually be able to fit the yoke on without it bumping the main board, and that makes it a bigger undertaking than I thought (plus the original Wobbulator build docs have a section on modifying/replacing the vertical deflection oscillator to avoid interference from the second yoke and I’m not totally clear whether that’s specific to the set they were using because the yoke was physically close to the stock oscillator, or whether it would be mandatory for any Wobbulator, so I’ll want to track down someone who has built one successfully already an ask some questions).

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It doesn’t count as hardware, but the ThriftBooks chain has about half a dozen paperback copies of TV Repair For Beginners on sale for a buck or two depending on condition (the hardcover isn’t showing up anywhere for less than $50 and most other used TV repair books are even more expensive)

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Someone’s selling a bunch of Horita SCT-50 titlers for $50 each:

Might be of interest. Not super cheap but considering they’re a current production item that has a $500 MSRP I think it qualifies as a bargain. Not sure if I’ll get one or not, it definitely looks cumbersome to edit titles from the front panel but it’s also the smallest titler I’ve ever seen and the software (which is freely downloadable from Horita) is new enough that it shouldn’t be a problem. Skimming the manual, it looks like it’s actually pretty capable, and you can daisy chain up to 99 of them and control them from software which is interesting.



Variant of the 4" Watchman-style CRT:

Same CRT, different (simpler) driver board.

I got mine (the other variant I posted a while ago) but haven’t had a chance to mess with them yet. Someone somewhere else pointed out that the raster has a really weird shape that makes them hard to work with, but I’m going to eventually try some electromagnet stuff, and worst case scenario I’ll use them for kaleidoscopic rescanning or something.

Also, not exactly cheap but I found some generic 21"-29" CRT driver boards for under $50 new and I’m seriously considering doing a full rebuild on the old 2-something inch Zenith I’ve got stashed in my back hall. The main board is so filthy I didn’t even bother trying to repair it (has about 3" of foldover, probably a bad cap or something from what I can gather but you can’t even read the components because they’re covered with caked on grime that won’t come off with canned air) but the tube itself works fine and it seems a shame to recycle it. New driver board and a new yoke would probably make it better than it was new, plus it would be a good learning experience. Maybe make some kind of 90s cyberpunk-looking aluminum and plexiglass case for it.

We bought this little thingy (Ground Loop Isolator, you can find dozens of variants with slightly different names, use cases and prices, and more or less sketchy looks) because it was super cheap (like 7 bucks) and it seems to effectively reduce video interferences/noise.

We put the isolator just before an LCD display, at the end of a very very dirty signal path: camcorder > Edirol V8 video mixer > monitor output > Panasonic AVE5 video mixer > monitor output > cheap splitter > LCD display.

We connected the side labeled ‘cable’ to the display and the side labeled ‘equipment’ to the splitter. The orientation makes a difference.

The signal is not fully clean yet: it looks like brightest picture cause some folding-like glitch in the image…but that’s much better-looking than before, when big vertical darker bands kept slowly scrolling horizontally across the screen.

We didn’t manage to take pictures showing the improvement but it is noticeable.


…less than 2 dollars on aliexpress:

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This EASYCEL HDMI to S-Video RCA Converter was 35 bucks. Results are better than with the other popular cheap converter (15-20 bucks, usually square and branded GAMA), as the image is way brighter. S-Video and RCA outputs can work at the same time.

Added to the wiki page.


Anyone looking for Pi zero’s in the UK to build a Recurboy, there’s plenty Pi zero 1.3’s here at the moment. (Cost £26). Just grabbed one and ordered my kit from @cyberboy666. Looking forward to building it :slight_smile:

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I should build one of those at some point, it would be really handy to have a second video player in the setup.