I can stop whenever I want

I don’t have a knitting machine problem, I could quit right now, I swear.

While working with my Toyota 747 I decided to try and find a ribber for it, which led me to the Ravelry Knitting Machine Sales group. I did not find a Toyota ribber, but I did find someone in Brooklyn who was selling a White/Superba 1602. He was selling it at a reduced price because the electronic selector box was not functioning.

White/Superba 1602

The Superba knitting machines, which were also sold under the brand names White, Singer, and Phildar, are really interesting machines. Instead of a main bed and an optional removable ribbing bed like most Japanese machines, the Superbas have two permanently fixed identical beds. This makes it much easier to get consistent, even ribbing.

Mechanically, the machine is in good shape. Stockinette stitch, ribbing, and jacquard patterning (done by manually moving the needles into place) all work well.

The selector box, which can be seen in Patrick’s photo stream, works by reading stitch patterns off mylar sheets. A photoresistor detects either a light or dark square and sends a signal to the machine which moves the needles accordingly.
In addition to maintaining a comprehensive site on Superba machines, Patrick also was kind enough to supply me with the users manual, service manual, exploded part diagrams, and logic flow charts for the electronics.

As soon as I opened up the machine and took out the circuit boards, it was clear things weren’t working properly:

Broken :(

I superglued the board itself back together, and then used lumps of solder to repair the broken traces. Jumper wires would have been better, but admittedly I was too lazy to get up and find a spool of wire.

Once the traces were repaired, Phooky helped me test the output voltages. Since it takes in 110V mains power, I was nervous to start poking at it by myself. But we only made the electricity arc between the multimeter probes once. Have I mentioned that mains power is kind of terrifying?

Anyway, of the four pins that connect to the card edge, two are tied together to ground, and the other two provide 24v for the motor drive (which feeds the mylar sheets) as 12v for the COP420 microchip.

Speaking of the COP420, my first instinct was to try to get a firmware dump off the chip and try to reverse engineer the firmware. Not that I have any experience doing that, but luckily Trammell does. Unfortunately, he found out that the COP420 is a mask-programmed device, meaning that the program is put into ROM when the chip is created, in contrast to something like the Atmega chips used in Arduinos. If you’re lucky, the “test mode” on the chip was initially enabled, making it possible (if somewhat of a pain) to read out the firmware.

The more I think about it, the more it makes sense just to redesign the selector box from the ground up. Most of the bulk and power of the box is related to the scanning and advancing of the mylar cards, which are adorably archaic but not exactly convenient. A USB interface would be vastly preferable, and would cut down on about 2/3 of the circuit. I need to do some investigating to see if the whole thing could be USB powered, eliminating the need for a separate power cord and bulky transformer.

Yeah, ok, I have a knitting machine problem.

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13 thoughts on “I can stop whenever I want

  1. Connie Rose says:

    This makes absolutely fascinating reading, I’d love to hear if you succeeded in getting the electronics to work, and also whether you achieved a working USB link? I love these Singer/Superba/White needle-beds and would like to buy a machine, but they are pricey here in the UK for machines with old electronics, that have no patterning facility (apart from ribs & racking) when the electronics fail as they are more or less bound to do. I used to have the ‘System 9000’ version, but the console packed up after 10 years. I’d buy another – or a light box machine – tomorrow if I knew you could create and sell to me (and others like me) a USB link and the software to operate it from a modern computer!

    1. Kellbot says:

      Hi Connie,
      I’m planning on working on the USB selector box once I get the original up and running (that way I have something to reference). A few other people have expressed interest, so we’ll probably do it as an open source project and document everything here. The holidays are pretty crazy for me, but I should have some time to sink into the project after the new year.

  2. const says:

    Hey, great post. I’m working on reviving on of those memomatics, but since I don’t have operational device to start with, and schematics supplied on superba knitting site are scanned very badly so I can’t read markings on edge connector, I’m curious if you happen to know voltage used for driving magnets on back carriage (15v?) for needle selection and voltage for rotary encoder built into back needle bed tied with cursor. All those connectors lead to 4 leads on right hand side of memomatic unit that connect machine bed to. Unlike pressure pad models that use internals rotary encoder, memomatic you pictured has it’s own, redundant, encoder inside driving over plastic shaft, placed between those 4 pins on machine bed connector. Any info would be appreciated, since model I’m trying to revive is quite beyond repair so I might have to build new one from scratch.

    1. I haven’t had a chance to look at this lately (much to my chagrin) but I do have a high-res copy of the service manual – and more importantly, the English translation for it. Patrick (aka the god of Superba knitting) was kind enough to supply it, and I’d be happy to share the PDF with you. Just let me know where to email it.

      1. const says:

        Thanks, I’d appreciate that very much! If you can, please send it to valsac@sbb.rs. So far I’ve reconstructed rotary encoder circuit on back needle bed, and it sends +5v signal back to memomatic circuit and is powered by memomatic (I guess Vcc here is +15v). Aside from that I’ve reconstructed power supply and it is based around voltage regulator 7815 so it seems it supplies 15v dc, and 24-27 ac since it has unregulated leads as well. Now I’m trying to understand how needle magnets on back carriage are powered. I understand one lead is coming from cursor (and it seems that driving belt tied to cursor is tied directly to +15v(?) (orange) wire that comes from memomatic. But I don’t understand yet how the signal is sent since cursors appears to be tied directly to +15v. Memomatic is counting needle position from rotary encoder pulses, it is powering cursor with 15v (?) but where is the “signal” for needle selection (seems like machine bed is used for that, probably by leftmost pin marked “self” if I could read it correctly from schematics). In any case, thanks for help and all input. Regards 🙂

  3. Charlene Tate says:

    Any progress on this idea? I love my Superba 48 & White 1602 machine and would be so happy to find a way to interface with computer!

    1. Kelly says:

      Unfortunately I haven’t had much time to spend on it, but if you haven’t looked at the Superba forums on Ravelry it’s worth a peek. A few folks have been working on getting something up and running. http://www.ravelry.com/groups/superba-knittingtm

  4. Brenda says:

    Do you still have access to a high-res image of the board? Would love to have a copy.

  5. Tony Locane says:

    Hi Kelly … I was the guy who sold you the White 1602. I have since moved out of Brooklyn and am now in Harlem. I came about your blog via Thingiverse. I found a few of your designs since I’ve recently bought a 3D printer to use in my art and have been learning it. I am glad to see you’re still playing with re-imagining the Suberba/White and potential computer interface. Hope you are well.

    1. Kelly says:

      Good to hear from you Tony! I haven’t made a ton of progress on the selector box, though I do use the 1602 a lot for hand manipulated stuff! Hopefully once my toddler is a little more self sufficient I’ll have more time to spend on the 1602’s internals.

  6. Dave says:

    Is it possible to get a copy of the high res scan of the service manual? My wife was given a Superba S28 without the electronics. I think I have it pretty well figured out but would like to verify things before I put power onto the machine. It looks to me like they keep the +15v on the cursor all the time and switch frame ground to pull in the solenoids. The rotary encoder amplifier board in the machine seems to be isolated from frame ground entirely.

    1. Kelly says:

      Hi Dave,
      I don’t have a better scan but I do have an excellent resource for working with the Superbas: check out Superba Knitting on Ravelry. You’ll need a login (free), but there are a couple different threads in there about the electronics in the patterning devices.

      http://www.ravelry.com/discuss/superba-knittingtm/topics

      1. Dave says:

        Thanks. I am already on the Ravelry thread. I have the machine internals pretty well figured out. I think that it will be pretty simple to set up full be patterning with an Arduino computer.

        Dave

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