Announcement

Collapse

Forum Rules and Etiquette

Our mission ...

This forum is part of our mission to promote the preservation of vintage computers through education and outreach. (In real life we also run events and have a museum.) We encourage you to join us, participate, share your knowledge, and enjoy.

This forum has been around in this format for over 15 years. These rules and guidelines help us maintain a healthy and active community, and we moderate the forum to keep things on track. Please familiarize yourself with these rules and guidelines.


Rule 1: Remain civil and respectful

There are several hundred people who actively participate here. People come from all different backgrounds and will have different ways of seeing things. You will not agree with everything you read here. Back-and-forth discussions are fine but do not cross the line into rude or disrespectful behavior.

Conduct yourself as you would at any other place where people come together in person to discuss their hobby. If you wouldn't say something to somebody in person, then you probably should not be writing it here.

This should be obvious but, just in case: profanity, threats, slurs against any group (sexual, racial, gender, etc.) will not be tolerated.


Rule 2: Stay close to the original topic being discussed
  • If you are starting a new thread choose a reasonable sub-forum to start your thread. (If you choose incorrectly don't worry, we can fix that.)
  • If you are responding to a thread, stay on topic - the original poster was trying to achieve something. You can always start a new thread instead of potentially "hijacking" an existing thread.



Rule 3: Contribute something meaningful

To put things in engineering terms, we value a high signal to noise ratio. Coming here should not be a waste of time.
  • This is not a chat room. If you are taking less than 30 seconds to make a post then you are probably doing something wrong. A post should be on topic, clear, and contribute something meaningful to the discussion. If people read your posts and feel that their time as been wasted, they will stop reading your posts. Worse yet, they will stop visiting and we'll lose their experience and contributions.
  • Do not bump threads.
  • Do not "necro-post" unless you are following up to a specific person on a specific thread. And even then, that person may have moved on. Just start a new thread for your related topic.
  • Use the Private Message system for posts that are targeted at a specific person.


Rule 4: "PM Sent!" messages (or, how to use the Private Message system)

This forum has a private message feature that we want people to use for messages that are not of general interest to other members.

In short, if you are going to reply to a thread and that reply is targeted to a specific individual and not of interest to anybody else (either now or in the future) then send a private message instead.

Here are some obvious examples of when you should not reply to a thread and use the PM system instead:
  • "PM Sent!": Do not tell the rest of us that you sent a PM ... the forum software will tell the other person that they have a PM waiting.
  • "How much is shipping to ....": This is a very specific and directed question that is not of interest to anybody else.


Why do we have this policy? Sending a "PM Sent!" type message basically wastes everybody else's time by making them having to scroll past a post in a thread that looks to be updated, when the update is not meaningful. And the person you are sending the PM to will be notified by the forum software that they have a message waiting for them. Look up at the top near the right edge where it says 'Notifications' ... if you have a PM waiting, it will tell you there.

Rule 5: Copyright and other legal issues

We are here to discuss vintage computing, so discussing software, books, and other intellectual property that is on-topic is fine. We don't want people using these forums to discuss or enable copyright violations or other things that are against the law; whether you agree with the law or not is irrelevant. Do not use our resources for something that is legally or morally questionable.

Our discussions here generally fall under "fair use." Telling people how to pirate a software title is an example of something that is not allowable here.


Reporting problematic posts

If you see spam, a wildly off-topic post, or something abusive or illegal please report the thread by clicking on the "Report Post" icon. (It looks like an exclamation point in a triangle and it is available under every post.) This send a notification to all of the moderators, so somebody will see it and deal with it.

If you are unsure you may consider sending a private message to a moderator instead.


New user moderation

New users are directly moderated so that we can weed spammers out early. This means that for your first 10 posts you will have some delay before they are seen. We understand this can be disruptive to the flow of conversation and we try to keep up with our new user moderation duties to avoid undue inconvenience. Please do not make duplicate posts, extra posts to bump your post count, or ask the moderators to expedite this process; 10 moderated posts will go by quickly.

New users also have a smaller personal message inbox limit and are rate limited when sending PMs to other users.


Other suggestions
  • Use Google, books, or other definitive sources. There is a lot of information out there.
  • Don't make people guess at what you are trying to say; we are not mind readers. Be clear and concise.
  • Spelling and grammar are not rated, but they do make a post easier to read.
See more
See less

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

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • rkrenicki
    replied
    Even after something like an FDISK /MBR? That tends to do the trick for me.

    Leave a comment:


  • blackepyon
    replied
    Originally posted by rkrenicki View Post
    I tend to stick with smaller cards for my XT class computers. 32-256mb in size, and I find that compatibility with these cards is very high.

    The only oddball are the Cisco 64mb cards which do not seem to boot on any of my Tandys. The boot fine on my NuXT, and an IBM PS2 model 35. What is weird is that I can read them just fine on my Tandys, just not boot from them. I think it may have something to do with the 2048 byte allocation size that they end up getting formatted with.

    32mb cards are my go-to nowadays since they are "large" for an XT machine, and do not have stupid long free space calculation times. Every brand of 32mb card I have tried on my XT-CF-Lites have worked so far.
    My CF cards are between 16-512 MB, but I couldn't get any of them to boot until I used Diskpart to "cleanall" on those cards in my Win10 machine. All said, you're right, there's no point in having anything larger on an XT class machine, even if you're using DOS 5 or 6, and can see 2GB partitions. However, sometimes you just use what you have lying around.

    Leave a comment:


  • rkrenicki
    replied
    I tend to stick with smaller cards for my XT class computers. 32-256mb in size, and I find that compatibility with these cards is very high.

    The only oddball are the Cisco 64mb cards which do not seem to boot on any of my Tandys. The boot fine on my NuXT, and an IBM PS2 model 35. What is weird is that I can read them just fine on my Tandys, just not boot from them. I think it may have something to do with the 2048 byte allocation size that they end up getting formatted with.

    32mb cards are my go-to nowadays since they are "large" for an XT machine, and do not have stupid long free space calculation times. Every brand of 32mb card I have tried on my XT-CF-Lites have worked so far.

    Leave a comment:


  • blackepyon
    replied
    Originally posted by Eudimorphodon View Post
    Man, I didn't even mention the best part of the circus (here). By fantastically unlucky coincidence a few weeks ago I happened across a stash of old CF cards of various sizes; mostly 128MB-512MB, but there were two 2GB ones, and for some idiotic reason I thought it a good idea to swap these CFs into *both* machines. (In one case because, you know, bigger than 256MB, and the other to free up the PATA->SD adapter I'd initially been using.) Apparently those CFs have compatibility issues with XT-CF though; despite seemingly working fine at first both machines gradually started acting buggier and buggier. The most common symptom was they'd crash with an "Invalid command.com" error when exiting programs, but they'd also crash halfway through booting, I'd get strange random crashes or obvious corruption inside software... basically both machines started coincidentally going to hell around the time I'd swapped boards a few times. To say the least I was getting to the pulling-my-hair-out-with-frustration stage of W-T-F. I was convinced that maybe I'd started cracking the motherboard traces from the stress of pulling the boards in and out. Finally, around the time I started realizing there was actual file corruption going on even with files that I'd never written back to disk it occurred to me that, wait, I'd swapped both drives around the same time...

    Anyway, put the PATA->SD (and smaller CF) back in and everything was suddenly fine again. AAAARGH. So, yeah, that totally didn't help with the narrowing it down.

    A good reminder of how it's a bad idea to change multiple variables at once, I guess.
    Somebody needs to start a thread for which CF cards are known to work/not work, and whether with the ISA-CF or the XT-IDE (8-bit PIO/16-bit mux). As well as which adapters they've had good results with.

    Within the collection that I have, I've also noticed that some cards are picky about master/slave configurations, which can also depend on which CF adapter I'm using, though all of them are fine as standalone devices. Some do not like to be a master when a slave device is present, but have no problem being a slave. Most people aren't going to run into this problem, though I should try to acquire a matching set of adapters just to make sure that's not what's causing the issue.

    Leave a comment:


  • rkrenicki
    replied
    The connectors arrived yesterday, and while I have not inspected every single one.. they seem to be perfect. They have a snug fit right out of the package, which I am very pleased with.
    20191204_221331974_iOS.jpg
    20191204_221356469_iOS.jpg

    The company I used is called Shenzhen RealRun Electronic Co. They typically have a MOQ of 1000, so I did end up paying a bit more per piece than normal for "only" ordering 250. They have a contact link on their Alibaba page here: https://realrun.en.alibaba.com/?spm=...621118397jvQ2r

    The part number is: "FH2.54*8.5-2*31P 0.64*0.4 Gold 1U PA6T"

    Otherwise, if anyone wants some small quantities, feel free to PM me here or since some of you know me on facebook, you can contact me there.

    Leave a comment:


  • Eudimorphodon
    replied
    Originally posted by RetroGaming Roundup View Post
    Oh man I "love" those gotcha type problems.
    Man, I didn't even mention the best part of the circus (here). By fantastically unlucky coincidence a few weeks ago I happened across a stash of old CF cards of various sizes; mostly 128MB-512MB, but there were two 2GB ones, and for some idiotic reason I thought it a good idea to swap these CFs into *both* machines. (In one case because, you know, bigger than 256MB, and the other to free up the PATA->SD adapter I'd initially been using.) Apparently those CFs have compatibility issues with XT-CF though; despite seemingly working fine at first both machines gradually started acting buggier and buggier. The most common symptom was they'd crash with an "Invalid command.com" error when exiting programs, but they'd also crash halfway through booting, I'd get strange random crashes or obvious corruption inside software... basically both machines started coincidentally going to hell around the time I'd swapped boards a few times. To say the least I was getting to the pulling-my-hair-out-with-frustration stage of W-T-F. I was convinced that maybe I'd started cracking the motherboard traces from the stress of pulling the boards in and out. Finally, around the time I started realizing there was actual file corruption going on even with files that I'd never written back to disk it occurred to me that, wait, I'd swapped both drives around the same time...

    Anyway, put the PATA->SD (and smaller CF) back in and everything was suddenly fine again. AAAARGH. So, yeah, that totally didn't help with the narrowing it down.

    A good reminder of how it's a bad idea to change multiple variables at once, I guess.

    Leave a comment:


  • RetroGaming Roundup
    replied
    Originally posted by Eudimorphodon View Post
    Would you be able to share the contact info for this vendor you found to do the work? I'm wondering if they'd charge in the same ballpark for custom-height shrouded male connectors. Maybe we could put together a group buy for people working on boards that include the stacking functionality.

    I find myself more interested in finding an easy off-the-shelf solution for getting the proper .7" spacing for the lower piggyback board since I finally found what was causing a maddeningly intermittent issue with the serial ports on my new board. I kept having this issue where the mouse driver would tell me "device not found" when booting in the 1000HX; it didn't happen in the 1000 EX, so I churned through all sorts of possibilities trying to find it. The punch line turned out to be that one of the jumpers on the RAM board in the HX was *just* tall enough to touch the bottom of the piggyback board and screw with it. .
    Oh man I "love" those gotcha type problems. A few years ago I restored a Xenon pinball for my collection and on initial power up the computer controlled bulbs were firing off like flash bulbs. Long story short, it turned out a prior owner had replaced a machine screw with a wood screw that had the exact same head, and it passed through the playfield and bridged 70v onto the bulb bus which is like 5 or 7v. It took days (weeks) of tearing apart the harness and looking for the cause to find that problem.

    Leave a comment:


  • Eudimorphodon
    replied
    Originally posted by rkrenicki View Post
    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.
    Would you be able to share the contact info for this vendor you found to do the work? I'm wondering if they'd charge in the same ballpark for custom-height shrouded male connectors. Maybe we could put together a group buy for people working on boards that include the stacking functionality.

    I find myself more interested in finding an easy off-the-shelf solution for getting the proper .7" spacing for the lower piggyback board since I finally found what was causing a maddeningly intermittent issue with the serial ports on my new board. I kept having this issue where the mouse driver would tell me "device not found" when booting in the 1000HX; it didn't happen in the 1000 EX, so I churned through all sorts of possibilities trying to find it. The punch line turned out to be that one of the jumpers on the RAM board in the HX was *just* tall enough to touch the bottom of the piggyback board and screw with it. (Just eyeballing it it *looks* like the battery holder is the tallest part, and I had a piece of electrical tape over the positive contact to make sure that wouldn't be a problem, but apparently eyeballs can deceive you. And of course this meant if I shuffled just the serial/IDE boards between systems, which I was mostly doing because I'm still running the old prototype RAM board in the EX which doesn't allow the optimal memory map for the HX, the problem went away because the component positions were different.) Taping an insulating sheet on the upper board solved the problem... but so would the proper extra .2" of clearance. (And also would be the "right" way, just in case someone actually wanted to mix new boards with an old Plus card.) Feh.

    Leave a comment:


  • rkrenicki
    replied
    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.

    Leave a comment:


  • blackepyon
    replied
    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.

    Leave a comment:


  • dJOS
    replied
    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!

    Leave a comment:


  • rkrenicki
    replied
    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.

    Leave a comment:


  • blackepyon
    replied
    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?

    Leave a comment:


  • rkrenicki
    replied
    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.

    Leave a comment:


  • blackepyon
    replied
    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.

    Leave a comment:

Working...
X