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Thread: I wish to create a new DMA/RAM expansion card for the Tandy 1000 line.

  1. #541
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    Quote Originally Posted by eeguru View Post
    Is there anyway they can do a proper double-tall male header with offset shroud like on the original RAM expansion Plus board? That way, whatever designs come out of this thread could be a proper replacement for the Plus RAM expansion allowing two more Plus boards to mount on-top.
    I haven't tested this yet because I'm currently not caring a lot about cross compatibility with original boards, but my ad-hoc measurements suggest that if I were to use a "double-ended" male header (they sell trimmable 2x40s at my local shop) and shim it while soldering I could get the "low" slot to the proper .7" spacing. (If you use a normal header you end up with .5".) Likewise using a normal header for the "high" slot and plugging in a set of trimmed "extra tall" stacking headers as an extender gets you about the right height for the upper slot. So it is *possible* to cobble it together. But it certainly isn't optimal. Shrouds would also be really nice. You could probably 3d print a sleeve to fit around the suggestions above but it wouldn't be fantastic.
    My Retro-computing YouTube Channel (updates... eventually?): Paleozoic PCs

  2. #542
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    Quote Originally Posted by blackepyon View Post
    Yeah, the 62-pin headers I've been getting from Digi-Key are too tight. The first couple that I ordered from a different manufacturer actually did fit properly, but they went out of stock. I'd definitely be interested if getting a handfull if you can get or find ones that actually fit properly.
    I don't have the original Tandy board to compare it with, but it does definitely give me the willies how much insertion/removal force it seems to take to get boards in and out of these machines with the headers I've been able to find. I'm frankly worried the traces are going to start cracking after too many cycles.
    My Retro-computing YouTube Channel (updates... eventually?): Paleozoic PCs

  3. #543
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    Quote Originally Posted by Eudimorphodon View Post
    I don't have the original Tandy board to compare it with, but it does definitely give me the willies how much insertion/removal force it seems to take to get boards in and out of these machines with the headers I've been able to find. I'm frankly worried the traces are going to start cracking after too many cycles.
    I'd say about 2-3x as much. This is fine if you're card doesn't have a back panel mounting bracket, and the socket is all that's holding it in place. Then it's not going anywhere.

    But you need to carefully wiggle it out a little bit each corner at a time.
    My vintage systems: Tandy 1000 HX, Tandy 1100FD, Tandy 1000 RSX, and some random Pentium in a Hewitt Rand chassis...

    Some people keep a classic car in their garage. Some people keep vintage computers. The latter hobby is cheaper, usually takes less space, and is less likely to lead to a fatal accident.

  4. #544
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    Quote Originally Posted by rkrenicki View Post
    I am working with a vendor in China to have some proper 2x31 headers made up rather than piecing together 2 other sized headers, or getting a 2x32 and chopping off one row. Once I get the particulars worked out, I will share my vendor, or if anyone wants a few.. I am planning on ordering plenty of extras.
    Did you manage to get those headers made? Adrian's latest video said you did. If so, I think everybody on this thread would be interested in getting a few.
    My vintage systems: Tandy 1000 HX, Tandy 1100FD, Tandy 1000 RSX, and some random Pentium in a Hewitt Rand chassis...

    Some people keep a classic car in their garage. Some people keep vintage computers. The latter hobby is cheaper, usually takes less space, and is less likely to lead to a fatal accident.

  5. #545

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    They have been made, 250 of them are in a DHL plane as I type this. I should likely have them on Friday or Monday.

    I did get a small sample of 5 that I have tried out, and I am quite happy with them. Yes, they are tighter than the Tandy board, but I really chock that up to being a brand-new connector with not yet stretched out contacts. I find that after a dozen insertions, they loosen up quite a bit. Since the Tandy cards have most likely been installed in computers for hte last 30 years, they are already pre-stretched out.

  6. #546
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    Quote Originally Posted by rkrenicki View Post
    They have been made, 250 of them are in a DHL plane as I type this. I should likely have them on Friday or Monday.

    I did get a small sample of 5 that I have tried out, and I am quite happy with them. Yes, they are tighter than the Tandy board, but I really chock that up to being a brand-new connector with not yet stretched out contacts. I find that after a dozen insertions, they loosen up quite a bit. Since the Tandy cards have most likely been installed in computers for hte last 30 years, they are already pre-stretched out.
    The ones I've been getting from Digi-Key do START to loosen after a while, but after pulling it out over and over on my XT-IDE card (probably at least 20 times for testing), I ended up lifting the solder pads joining the back plate PCB. I'll have to add some THP vias to the pads for the next rev before I put it up on GitHub, maybe 30-40 mils or so, something that you could flow solder into for reinforcement.

    How much you figure to sell them for?
    My vintage systems: Tandy 1000 HX, Tandy 1100FD, Tandy 1000 RSX, and some random Pentium in a Hewitt Rand chassis...

    Some people keep a classic car in their garage. Some people keep vintage computers. The latter hobby is cheaper, usually takes less space, and is less likely to lead to a fatal accident.

  7. #547

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    After shipping, they worked out to about $0.47/ea in the quantity that I bought. I'd just round up to $0.50/ea plus shipping.

  8. #548

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    Quote Originally Posted by rkrenicki View Post
    After shipping, they worked out to about $0.47/ea in the quantity that I bought. I'd just round up to $0.50/ea plus shipping.
    Gee that’s impressive!
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  9. #549
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    Quote Originally Posted by rkrenicki View Post
    After shipping, they worked out to about $0.47/ea in the quantity that I bought. I'd just round up to $0.50/ea plus shipping.
    So that rounds to, what? ~$120 USD to get the batch of 250 made? If the quality's reliable, that's a really good deal. Who did you go with to get them made? There's probably other (now) defunct connectors we can think of to get made up.

    Do you have a Paypal or something set up? I figure to order a batch of 10. That should keep me going for a little bit.
    My vintage systems: Tandy 1000 HX, Tandy 1100FD, Tandy 1000 RSX, and some random Pentium in a Hewitt Rand chassis...

    Some people keep a classic car in their garage. Some people keep vintage computers. The latter hobby is cheaper, usually takes less space, and is less likely to lead to a fatal accident.

  10. #550

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    The connectors themselves were $0.30/ea but DHL shipping and bank fees are what increased the price by 50%. Even then, they are far cheaper than $3-4 per connector from Mouser or Digikey..

    It's a good deal as long as the 250 are the same quality as the sample 5 they sent me. Once they get here, and assuming they are all in good condition, I will be more than happy to share the manufacturer. But yes, I dont mind parting with small quantities once they arrive.

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