In this video I take a look at the Spectravideo SV-601 super expander, and come across a few surprises along the way!

This time around we’re repairing a Commodore 1084S-P1 monitor (originally made by Philips). For those wondering about the doubled up insulator on the heatsink – I checked after running the monitor for 30+ minutes and the heatsink was the same temperature as the transistor (approx 35 degrees C), so the thermal conductivity doesn’t appear to be compromised.

This time around I put the Vectorio back together. There’s no real surprises here – it all bolts back together about the way you’d expect. Next time around I hope to have a working composite monitor that I can plug into it (my modern Sony LCD workshop TV doesn’t like the composite output from many retro machines).

Another tip shop find – this time a Macray CCTV switcher thing. Not entirely sure what this is supposed to do, other than switch video in a CCTV system. It’s pretty basic, with a PSU and a bunch of relay boards. I bought it for the Euro card enclosure.

This time around we take a look at a monochrome 9″ Apple ][ monitor, and make a start on rectifying its issues. This will be part 1 of at least 2 as I’m still waiting on some of the replacement parts to arrive (some I had in stock, but many I didn’t). You’ll see what a PITA this thing is to get apart, and next time I expect you’ll see what a PITA it is to put back together! ...

Another tip shop find – this time a PACOM 3170 video “thing”. I realised after I made the video that the identification overlay that I think this produces would require a video source to generate that, and the video cards don’t have that, and it’s unlikely the microprocessor is bit-banging the video. BUT, I missed the obvious – there’s provision for a daughtercard on each video card, with pins labelled “VSYNC, HSYNC, ID VIDEO” amongst others on one side, and the other side has serial in/out, ID0-3 pins (device select?). ...

In this video I clean and re-assemble the Vectorio keyboard that I took apart quite some time ago. In doing so I noticed another area where this machine differs from the genuine Apple ][+, so I explore that a little before giving the keyboard a test. AND IT DIDN’T WORK PROPERLY! But it wasn’t a huge issue, and the fix was pretty straightforward if not slightly fiddly.

A while back now I picked up an Apple II clone on eBay – listed as “unknown condition – parts only”, or words to that effect. Back then I popped it open, checked the power supply for obvious issues, checked the output voltages, and was able to successfully power up the machine. BUT, the machine was a bit of a mess – the case is very yellowed for one, and it needed a good overall clean. So I pulled it all down and made a start, but that was about the time I ran out of space in my little home office, making it very difficult to get anything done in there. That was the driver to build a new workshop for this stuff! ...

In this video we’ll have a look at the cassette system of the Spectravideo 328. How it connects to the system, a look inside the SV-903, and a quick look at some cassette based software. Note: I didn’t mention it in the video, but there are virtual tape solutions available for the SVI-328 – links below. Details of the Spectravideo tape format SVI-CAS owners manual link: The manual has recent pricing for the unit & SVI cable. ...

This set of Logitech X540 speakers were plugged into our bedroom TV to make it sound half decent. Most people seem to use those sleek sound bars, but I had this set of speakers sitting idle and for nearly 10 years they’ve done the job just fine. Until the other night when I turned them on and… Nothing. Nada. Zilch. So in this video I break them open to see what the problem is, and whether I have the parts required to fix them lying around. ...

In this video I unboxed a Spectravideo SV-328, an 8-bit computer from Spectravideo that was introduced to the world in 1983. I’ve never owned, or even used, one of these machines so this was interesting. I picked this lot up from the local tip shop – yup, someone was literally throwing this out! In part 1 of this series, I take a look at it, plug it in, and check if it works. I also pop it open to see if anyone else has been inside modding anything. ...

I said I’d likely do a video of the second G413 repair, and I did exactly that. This second one had an identical fault, just on a different key (the ‘E’ key), and the fix was exactly the same. So despite the comments I read when I was Googling around that it’s the keyswitches themselves that are the problem, this hasn’t been my experience. That’s not to say that people haven’t had issues with the keyswitches – just that I haven’t. ...

OK, I admit it, I’m currently using Microsoft Edge as my preferred browser – on both Windows and Linux. Mostly because of the ability to put the browser tabs down the left side of the window, which is particularly useful on wide-screen monitors where there’s no shortage of horizontal real-estate. Chrome has extensions that can sort of do it, but it’s not as clean as the built-in Edge implementation – and Edge is really just Chromium under the hood anyway… ...

A quick look at the Sheen 100 video sport system from the late 1970’s, including some technical documentation and a brief session playing some of the games with my 15 year old daughter, who had some quite hilarious reactions to it all!

I’ve been using a couple of Logitech G413 keyboards for a while now – one on my work PC, and one on my “use most of the time” home PC’s. At least I was, until they both developed faults. The keyboard on my work PC developed a faulty ENTER key – sometimes it’d be fine and other times I’d get two keypresses instead of the one. That was particularly annoying when answering a prompt where the default was not what I wanted, causing me to have to do “something” again. ...

It’s been a couple of weeks since I’ve streamed anything – partly because I’m mulling over the best way forward. Live streaming is great, but it’s hard to concentrate on the task at hand when there’s an audience right there to also engage with – my hat is off to those who can concentrate on both at once! That, and sometimes I’ll hit a road-block and need to research things for a bit (or even wait a week for something to arrive), and that doesn’t make for very engaging content :-) ...

So the current state of play is that IC42 (which was a VC2069) has been replaced with a VC2023 borrowed from a model B. They’re pin compatible (and I believe functionally compatible). I now have: pin 8 – 16Mhz in pin 7 – 8MHz out pin 6 – 4MHz out pin 5 – 2MHz out pin 4 – 1MHz out BUT, the 2MHz out, while it makes it to IC34 pin 2, doesn’t make it to IC28 pin 3, which results in no 1MHZE signal being generated – and that’s used by the VIA’s, they keyboard, and in various other places. So a bodge-wire corrected that, and now I get the 1MHZE signal in the relevant places. ...

I’ve been testing with it powered from the bench PSU today (albeit without the -5V, but IIRC that’s only required for audio/serial/cassette). As far as progress, I removed IC42 (destructively – cutting pins) and socketed a spare video ULA – now I’m getting the output clock signals that I’d expect to see, and the CPU is receiving a 2MHz clock. Initially RST was stuck low on pin 40 of the CPU, yet was going high everywhere else (tube socket, cartridge slots, etc). Closer inspection showed some noise on the RST signal at 2MHz, which made me suspect some sort of connection between pins 39 & 40 on the CPU. A clean of the PCB in that area resulted in RST going high on pin 40 as expected – so perhaps that “dust” on the board is more conductive than it looked… or something else was going on that cleaning somehow resolved. ...

I recently acquired a “may not be working, for parts” BBC Master 128. So I’m not entirely surprised it doesn’t work. Was pretty filthy, and for the most part still is. Battery pack was 3 x Duracell’s that had sweated fairly badly, but not corroded in the normal way they do. That’s been removed (and not replaced yet). Part of the top of the PSU was rusty, and the top of the video modulator is rusty. ...

Most of the IC’s are now in their sockets (on the CPU card at least). Getting close to being able to fire it up – just need the DS1210, and the PLCC adapter so I can do the initial programming of the flash memory. Live streams on Twitch ...

A couple of nights back my streaming PC got angry with me. The first night it bluescreened once, but it rebooted and the show went on. The second night, I think Obs crashed once and it bluescreened twice. Initial thoughts were maybe it was a driver or something that I’d installed recently, but that seems less likely now. This morning I created a Memtest86 USB stick and booted into it. Not long after it started throwing memory errors, and 4 hours in it was pretty messy (see pic above). ...

This Apple ][ clone arrived in the mail today. Mightly yellowed, but other than the ‘K’ key, the machine seems to work fine. The motherboard is branded “Vectorio”, so it’ll be interesting to learn a bit more about this one. Live streams on Twitch

After the last BBC stream I pondered that maybe the suspect disc drive’s heads were just dirty, so we clean those. Then investigate a couple of Master Compact systems, and end up opening the Amiga again to work out which Kickstart ROM it had (1.3) and realised it had a mono video output! Streaming PC bluescreened towards the end, but we picked up where we left off. ...

More Z80 board build… Live streams on Twitch

Recently I started putting together a Z80 based system from the Retrobrew Computers web site. The build is fairly well advanced, but I’m still waiting on some parts to finish it off. The Z80 Backplane is mostly done – I went with the 8-slot backplane because 3 was too small, 4 was borderline, and 12 was too big. I figured with an 8-slot board I could start by populating 5 connectors and add the others if I need to. ...