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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.
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Unique S-100 computer (Z-80/Vector Graphic/Micropolis)

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  • MikeS
    replied
    Originally posted by nullvalue View Post
    LOL I did do this with a real fluorescent fixture - I had one for plants/seed starting - not CFL or LED. I swear I can't make out any pattern at all.
    Well, there is the possibility that the speed is too far off; time to check it the hard way as Mike suggests

    Leave a comment:


  • deramp5113
    replied
    We can rough check timing with a scope. Measure sector to sector time by monitoring test point 3, negative edge triggered. Note you’ll have a half-sector time slip in periodically at the index pulse. What interval do you measure?

    Leave a comment:


  • nullvalue
    replied
    LOL I did do this with a real fluorescent fixture - I had one for plants/seed starting - not CFL or LED. I swear I can't make out any pattern at all.

    Leave a comment:


  • MikeS
    replied
    Originally posted by deramp5113 View Post
    You can pick out the pattern even with an incandescent bulb. Not as obvious as fluorescent, but it’s there.

    Mike
    True enough, but incandescents are getting as hard to find as 'real' fluorescents and certainly not nearly as clear. But if that's all you've got...

    BTW, Mike, let me take this opportunity to thank you for your many contributions to the hobby!

    m

    Leave a comment:


  • deramp5113
    replied
    You can pick out the pattern even with an incandescent bulb. Not as obvious as fluorescent, but it’s there.

    Mike

    Leave a comment:


  • MikeS
    replied
    It has to be a 'real' oldskool fluorescent, not a newfangled compact fluorescent (CFL) bulb, or you could try an LED powered from a low-voltage AC power brick through a resistor.

    Leave a comment:


  • nullvalue
    replied
    So I put the drive under florescent light and attempted the speed test. There is just a blur of the wheel, no appearance of a slow spin or standing still. I adjusted the pot (tried both the top and bottom) and no adjustment seemed to make any difference whatsoever.

    Leave a comment:


  • nullvalue
    replied
    Originally posted by deramp5113 View Post
    The manual you posted has the connector information so you can know for sure in future.

    If PCFLOP was able to write and verify the disk, then it should boot unless you have RAM problems. Use the monitor to test RAM from 0000 to DFFF and let it run for a while.

    Mike
    Yes, very odd that I could run the disk creation but that I couldn't boot. How long does boot from disk typically take? Just a few seconds, right?

    I let the memory test run for over an hour. From what I can tell, I got 0 failures: 20200524_095448.jpg

    Yes there is a white disk with a strobe pattern. I will attempt the speed test.

    Leave a comment:


  • deramp5113
    replied
    Originally posted by nullvalue View Post
    However, I am unable to boot from it using the 'B' monitor command. The disk drive engages but just spins and nothing happens.
    The manual you posted has the connector information so you can know for sure in future.

    If PCFLOP was able to write and verify the disk, then it should boot unless you have RAM problems. Use the monitor to test RAM from 0000 to DFFF and let it run for a while.

    Mike

    Leave a comment:


  • deramp5113
    replied
    Look on the hub pulley. Is there a strobe pattern printed on a white disk? Just watch in a room with (ideally) fluorescent lights. It should appear to stand still while the motor spins. Most likely it will appear to move forward or backward slowly. You can then adjust a pot on the board in the drive cabinet as detailed in the manual you posted the link for to make the pattern stand still.

    Mike

    Leave a comment:


  • nullvalue
    replied
    Actually I just realized I hadn't tried something after my adjustments.. I was never sure which head connector went to which drive on the internal board. Every test previously I'd swap the connectors around in case they were backwards. So now I swapped them and I was able to get a successful write! It said the disk was created at the end. I wrote the 56k "Vector CPM for Micropolis.vgi" image. However, I am unable to boot from it using the 'B' monitor command. The disk drive engages but just spins and nothing happens.

    How would I check the strobe lines? The speed seems ok but how can I measure it? The belts do seem a bit loose.

    Leave a comment:


  • deramp5113
    replied
    Actually, before we look for a write issue, have you looked at the 60hz strobe lines on the hub disc? How is the drive speed?

    Mike

    Leave a comment:


  • nullvalue
    replied
    Yes I believe this is it:
    http://www.bitsavers.org/pdf/micropo...nual_Feb79.pdf

    The board pictured in 4-3 is very similar to mine. There are some differences with connector positions but its the closest I've found. The schematic starts on page 132.

    Here is a closeup of my drive cabinet board
    20200522_205335.jpg

    Leave a comment:


  • deramp5113
    replied
    I would normally start looking on the drive PCB first, but your drive cabinet has a single board that controls two drives instead of a board per drive. I only have schematics for the latter. Have you found and downloaded schematics for the PCB in your drive cabinet? If so, point me to it and I’ll download a copy.

    Mike

    Leave a comment:


  • nullvalue
    replied
    That's fine with me trying to troubleshoot write operations - how would I test write paths?

    Leave a comment:

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