Commodore 64 repair, machine #2

So the prior Commodore 64 audio issue had seemed to be resolved, but when I went to test it with an actual demo it didn’t seem to work. Frustrated I figured I should look into the 3rd C64 that was given to me by Matt C and Mike W. It came from the surplus of Grande Junction in VaBeach, but had markings on it like it had come from CHKD Thrift in it’s past.

Originally there was no life on powerup, but then that changed. It was spotty and upon poking around the glass fuse holder was to blame. Reflowed solder on it and it will still problematic, cleaned the fuse and holder and it was still spotty, bent holder to get tighter grip on fuse and that cured it.

Next sympton was pink screen, orange screen, but not working. Searching online I found a bunch of pointers to things I had already tried (voltage checks.) Finally pointers said it might be the PLA chip, so I desoldered the one out of the donor board (#2) that supplied the SID chip for #1, and placed it in the socket of #3. Came to life, and there was sound from the demo loaded from the SD2IEC.

The metal shielding in #3 was way rusted, and bottom plastic heavily stained. So I combined some parts from #2, and wirewheel cleaned the top shield (which acts as heatsink for ICs.) I sprayed it with yellow rustoleum paint and it looks like a sad Tonka truck but it will perform it’s function and hopefully not rust more.

So check mark on a C64 finally. Claude and Tom are printing me a case for the SD2IEC — whoot! Now to find more d64 images.

LED Video Screen Update, it’s done!

A little bit late on this post, but the screen was 100% before MAGFest 2017. 6 frames each containing qty 9 32 pixel x 16 pixel modules are complete. I want the metal ones like the rental screens, but in the meantime it will suffice! The screen is 3 meters wide by 1 meter high, or can be setup as 6 meters wide by 1/2 high. I have the drivers on hand to split it into 2 or 3 separate units as well.

Power consumption can hit 12 amps. There is 480 amps of 5V power behind the screen. 4 modules have color issues (very red), I have spares but have yet to swap them.

LED Expansion 3

QSC BASiS / QSC Dataport to XLR adapters

MAGFest was approaching and I found a sweet deal on a few QSC BASiS units. For the record, I love QSC hardware. I’ve owned a few Digital Cinema amplifiers for many years, as well as a CX series. My goal back then was to have the THX cinema certified amplifiers for my home theater, and at the time people weren’t so aware of eBay. The amplifiers did suffer an issue or two which I suppose can be the subject of another post. There is a service bulletin.

But back to the BASiS units. I was after some QSC units from their RAVE series that use an older standard called CobraNet. CobraNet does UDP broadcasts of audio packets, raw PCM uncompressed. The RAVE units that do analog tend to catch quite a bit more, but I stumbled onto the BASIS units which are meant to hook straight to the QSC amplifier dataports. The dataports are DB-HD-15 (think VGA) connectors that hook to management processors. Note – Don’t use a common VGA cable, all pins must be wired straight through and many VGA cables share grounds among a number of pins.

Doing some research online I found there is no issue making breakouts that go from DB-HD-15 to XLR or RCA, and QSC even sells a breakout board with screw terminals. Sweet!

The bad news? Didn’t get the network working enough in the MAGFest arcade in 2017 to get it working. Next event, and in the meantime I will use my BASIS boxes with my amps to run audio around the house. Once the network is segmented so that the broadcast traffic from the audio doesn’t cause the WiFi to fall over….

And new blog started

I’ve been hammering through a ton of projects recently and decided I need to kick off a blog about them — mainly for my own notes. But some of the information should be shared with the world at large.

I used to post on the 757labs hackerspace blog, but since that’s mostly archival now this will be the new repairs and info spot.

I still need to figure out some workflow stuff — mainly posting of pictures inline. I moved to using Imgur more than Flickr as I don’t like the newer Flickr interface. Not sure if Imgur will do resized direct linked images. We’ll see!

Also I’m not on the current theme. In time will tweak it. For now tho, content.