• Fairlight,  Repairs,  Synths

    No longer blowing fuses, but….

    Having swapped out the bridge rectifier for a high power one and used nice high grade thermal paste I was able to power up the PSU and sure enough, it worked, I can measure the voltages and the mains fuse does not blow. Awesome, I’m really chuffed with this. So I assembled everything (about 2 hours) and powered her on.Only to discover another fault… ARGH!!! Sadly, the -12V rail is dead… Now I’m imagining the worst, so I decide to check the -12V fuse and well, it’s blown. Upon checking someone has replaced the 2A anti surge fuse with a a 1.5A standard blow fuse. So I power off, quickly…

  • Fairlight,  Repairs,  Synths

    We have a winner!

    I finally decided I could no longer avoid removing the PSU from the case to check the capacitors, rectifiers and transformer.Now if you recall I had a problem with the scan of the service manual in that the colours of the wires were not clear. I asked on the facebook group and David Cilia kindly took a photo of the area I was interested in and it’s so nice to see the colours. David also sent me pictures of the full page (left hand side and right hand side), Peter Welik also sent me another picture of the page I needed, wonderful! So please give his web site some love,…

  • Fairlight,  Repairs

    Pop goes the fuse

    I’ve been doing some more work on the Fairlight and trying to figure out what is causing the fuse to keep blowing. This time I’ve been hunting for the power supply, and it’s an interesting hunt. First step is to remove the back panel, which I’ve done before, lets reveal part of the power supply, the part with all the heat sinks and big power transistors used for the linear power supply. And yup, they are big, keep in mind this thing has a LOT of power, 24V at 5A, 12V at 2A, -12V at 2A and not forgetting the 5V at 16A, yes 16amps! That is a lot of…

  • Fairlight,  Repairs

    Fairlight, an interesting discovery

    So I decided to check a few of the PCBs, now this is a IIx so it should have voice cards with CEM3320 filters on, but no matter where I look I cannot find them. After a bit of digging, it seems the owner says it was a I, then upgraded to a II and then a IIx, but it looks like they kept the voice cards from the I. This uses a switched capacitor style VCF (top left using a 4066 and a 4136 quad op-amp). A friend shared a picture of his Fairlight II voice board and the CEM3320 is on the bottom left (you can see the…

  • Fairlight,  Repairs

    Fairlight CMI Series IIx repair…. Part 1

    So, I’ve been asked to fix a Fairlight series IIx, I don’t often do repairs but the chance to actually use one of these rare beasts was too much to turn down. Now I have removed the cover on this before the picture, it’s sat on top. This Fairlight died in the late 90s and has been left like it since, every time you power it on it blows the mains fuse, a 3.15A anti surge fuse. So before power it up again, I removed all the cards, and disconnected all the internal power harnesses (floppy drives, etc). My concern is that something on one of the cards, keyboard(s) or…

  • Repairs,  Synths,  TTL CPU

    Welcome

    I thought I’d move away from so called “social media” due to the increase in far right extremism, bigotry and general hatred in the world. This is a shame as I’ll miss a lot of the people I follow on twatter, faceprat and so on, but for my own mental health it’s time to move on. So I’m here to talk about random tech things I find interesting, maybe update on some of the more tech points of my synthesiser projects and certainly share posts of the odd repair job I do. I’m also working with a friend, Jon, on building a CPU entirely out of TTL logic chips which…