(Topic ID: 242158)

DumbAss test and reproduction PCBs

By DumbAss

4 years ago


Topic Heartbeat

Topic Stats

  • 1,541 posts
  • 230 Pinsiders participating
  • Latest reply 4 hours ago by ChrisHibler
  • Topic is favorited by 433 Pinsiders

You

Linked Games

No games have been linked to this topic.

    Topic Gallery

    View topic image gallery

    s11_cpu_c58.jpg
    IMG_2252 (resized).jpg
    20240112_212911 (resized).jpg
    IMG_0859 (resized).jpeg
    IMG_0858 (resized).jpeg
    IMG_0862 (resized).jpeg
    mismatch (resized).jpg
    good (resized).jpg
    boards_355.jpg
    boards_354.jpg
    boards_353.jpg
    boards_352.jpg
    boards_351.jpg
    boards_350.jpg
    boards_349.jpg
    DSCF3077 (resized).JPG

    You're currently viewing posts by Pinsider harig.
    Click here to go back to viewing the entire thread.

    #130 3 years ago

    that´s what we did on purpose in highshool
    ...and letting glow the pencil lead (0,5mm) when connected to a min. 3amps power supply

    1 year later
    #648 2 years ago
    Quoted from DumbAss:

    Playing catch up. I will be playing this game for some more weeks to come. Local service/repair interruptions have happened and will likely continue. This will affect the catch up game. In order to facilitate my sanity I grouped outstanding builds into batches. Building in batches is slightly faster than task switching due to the overhead of switching.
    As a reminder all boards are verified on my bench and some are verified in a machine (machine verification is required for high voltage as I do not have high voltage on my bench - it's too dangerous for my liking). I also have purpose built boards for board verification (other than the bench testing boards) that I can provide some information on if there's interest. These boards work but aren't perfect. Their purpose is to verify the production boards so they don't need to be perfect.
    This (first) batch is complete. These are all packed and will go out today! Then on to the next batch.
    [quoted image][quoted image]

    You are not hand soldering all that boards, right?
    Do you have your own wave soldering machine?

    #650 2 years ago

    Wow, thats a lot of work
    I am just rebuilding the lower part of a wpc89 cpu after an alkaline repair and have build some Sys11 led displays before and was wondering about the labor-but that is still small compared to your e.g. PDB boards

    Thx for your detailed answer and your work here in general

    1 month later
    #727 2 years ago
    Quoted from DumbAss:

    Thanks for all the kind words!
    I finished a pack batch over the weekend and I have a small number of left over boards that are a part of orders that were waiting for components that arrived yesterday.
    I also got some boards in (locally) that needed repair. I am always scared when I see previous repairs. They are often (not always) poorly done and have residual problems. I always suspect prior work/repairs and though I don't like being so cynical it's unfortunately proven to be true quite often. This particular board was interesting. The short (no pun intended) of the problem was that whoever did the repair tied D1 and D6 together so whenever solenoid 2 fired then both solenoid 2 and 7 would fire. Whenever solenoid 7 fired both solenoid 2 and 7 would fire. Same with solenoid 10 and 15 as well as 18 and 23 as well as 26 and 39. It also wreaked havoc on the lamp matrix as you can imagine. I usually like to clean up repairs better than this but the use of the SIP sockets means I won't touch it and only do the minimal amount of work. I stay far away from repairs that use SIP sockets.
    Before:
    [quoted image]
    After:
    [quoted image]
    In between these small tasks I spent some time on the unified System 3-7 board. It was definitely rushed as there are some interesting problems. Ultimately there's a fundamental problem in this REV-00 that will prevent System 7 boards from working at all. System 6 boards should work but alas ... neither of them work.
    Technical summary of state for those interest:

    The address for the SRAM region of the address map is not correct. Williams made a change to System 7 that I didn't factor in. This is due to my ignorance of System 3-7 in general. It also definitely does NOT help that I do not have working System 6 or System 7 boards as a control ("gold standard"). I may eventually need a set if I can't figure things out but I'm not at that stage ... yet.
    The diagnostics for System 6 (two LEDs) and System 7 (digit) are not correct. They're reversed. I read "7400" and thought "AND" but it's actually "NAND" so the BCD to the 7447 is inverted. The System 6 LEDs are reversed as well.
    The good news is that the Leon works. That means the CPU is executing and the basics of address decode is working.
    The bad news is that the ~BLANKING signal stays low (active) and there is no activity on the strobe lines. This is a good indicator that the software is either hung or in some form of infinite loop. The error in SRAM mapping should not affect System 6 execution so this is puzzling to me. This needs more investigation.

    The (Williams) universal numeric display works but has a signal input error. I swapped the BCD inputs so there is a workaround that does not require a new board but there is also some other small issue I need to investigate on the board that may require a revision either way. A feature I (attempted) to add to this board is brightness adjustment and it does work but requires more components. The workaround (cable) is shown in the following image.
    [quoted image]
    I generally take my time when trying to figure out problems. I don't always get things immediately and sometimes it takes a while for the penny to drop. This is why things take time for me to do. I am guessing that I will spend a little more time looking at some of these outstanding issues to make a decision on if I need a new board revision. I like to get board fabrication orders sent with priority because while being fabricated I can do something else. If I reverse that order of operation and build first before fabrication I can potentially spend time waiting for fabrication that could be used in other better ways. A little like overlapped I/O for those familiar with old Windows programming.
    <tl;dr>
    For those that like to read large wads of text with nothing better to do and are interested in the differences between System 6 and System 7 SRAM ... read on.

    System 6 has two physical RAM ICs of $0080 (128) bytes in size mapped at $0000-$007F and $0080-$00FF. They form a single logical unit of $0100 (256) bytes (JBOD in RAID terminology). The CMOS IC is $0100 (256) nibbles (4 bits not 8 bits) used to hold settings and is mapped at $0100-$01FF.
    System 7 has two physical RAM ICs of $0400 (1,024) nibbles in size mapped at $1000-$13FF. Each nibble of the byte is written to different units (striping in RAID terminology). The CMOS IC is the same ($0100 nibbles mapped at $0100-$01FF). To maintain compatibility with System 6 the hardware maps $0000-$00FF to the first $0100 bytes of the regular RAM - in essence a double mapping (two addresses map to the same physical location).

    This is the detail that I missed in REV-00. I just mapped everything at $0000 assuming the software knew that $0100 was the CMOS location. The problem with this implementation is that writes to $1100 will overwrite the CMOS at $0100 as they aren't directed to different physical locations. This is why System 7 will never work on the REV-00 board and requires a revision.
    </tl;dr>
    As mentioned above I do not plan to spend too much time on this as I still have outstanding big boards to build. I just need to take a small break from that to recharge. If you're still waiting for a board I will resume building within a few days.

    What is the issue with repairs involving SIP sockets?

    3 months later
    #824 1 year ago
    Quoted from DumbAss:

    Update.
    Been busy building boards and building boards. June was WPC-89 month. July is System 11 month. It's weird how boards seem to come in batches. August is another System 11 month with some System 9.
    Here is the new toy that my friend got me. It's an interesting machine. If a search is made for "lead bending tool" you get the plastic "triangle". If a search is made for "lead bending machine" you get these blue things. They are somewhat pricey and there's only a small number of merchants that actually have the machine in the US. They are HEAVY. Solidly built. All the other merchants are in China where the machines come from. Shipping is almost as expensive as the machine itself (due to the weight).
    This is the machine.
    [quoted image]
    It requires cut/tape (or reels). I loaded up a small amount. The amount is 69x 103K. This is the amount required for the System 9 CPU board.
    [quoted image]
    Turn the crank a bit and this is what comes out at the output end.
    [quoted image]
    This is what the belly of the machine looks like.
    [quoted image]
    Turn the crank some more. Keep it going.
    [quoted image]
    The output end of the machine.
    [quoted image]
    The whole cut/tape has been processed.
    [quoted image]
    This is what you get in the output tray.
    [quoted image]
    One batch complete. Another two to go. Load them up and turn the crank.
    [quoted image]
    15 seconds later you get this.
    [quoted image]
    So I got 3x batches of 103K capacitors for 3x System 9 CPU boards. All I need to do is put them in the board. The machine doesn't make soldering any faster though. A wave soldering machine will do that but we've discussed that before.
    I found that the best way for me to deal with this is NOT to do a whole bunch of cut/tape of the same value at the same time. If I did 500 of these capacitors then I would still need to count out 69 individual capacitors from the 500 and that takes time. So I've settled on cutting the required amount and keeping that as a template. Then the next time I need that amount for a board I just get the template and match it up to the reel and cut it off. Load up the machine and turn the crank. Exact number. No counting. No messing around. The reel keeps things organized until I need the required amount. For components that need only a small number (like less than 5) I crank a bunch of them and just count out the small number required from the output. I'll probably adjust things if need be to try to be more efficient.
    What took maybe hours or preparation (in front of the TV) now takes less than an hour to get everything ready. The machine is not easy to adjust and I've got this one correctly adjusted for 12.70mm. I decided to buy another two machines. One for 10.16mm and one for 15.24mm. Those are the other common pad spacing sizes used on the boards I make. Anything bigger (such as 20.32mm or 25.40mm) I will do by hand. Those sizes are not used often and if they are used the numbers are small (except the 6A4 on the power driver boards). I am still waiting for these other machines to arrive (they were shipped by sea but still cost a small fortune to ship).
    Also ... I revised this board and slipped building it in between some of the bigger boards. There is a small demand (pressure) for this so I wanted to make sure it at least works for 7-digit. I am unable to test 6-digit so I will be sending this out to another Pinside member for testing. If it works with 6-digit then there's a board heading to ChrisHibler when I get a chance.
    [quoted image]
    Note the System 11 Sound board underneath the foam. I got that verified working the other week. I took the board to a friend's place. He has an oscilloscope and that proved the digital and line level analog output was good. I suspected it was the amplifier but this was the proof. I had this board fabricated on 2020-01-12 so I have been sitting on it for 2-1/2 years. Having shown it was the amplifier I replaced the amplifiers and tried it again. I originally put eBay purchased TDA2002s as there was no reliable source at that time. These amplifiers caused one of the resistors to heat up really quickly (I used my thermal imaging device to see the heat). I replaced the TDA2002s with TDA2003s and it works. Now I need to give it a real machine test. I haven't gotten around to that yet.
    Finally ... I have a fabrication order that should (hopefully) arrive by the end of the week with a new reproduction request for someone local. It also contains a special surprise that I will build when I get some time to build and post it here when complete.

    That looks like a great machine and even fun to operate it. Seems to save you a lot of precious time to be used for more important things than bending wires at hand

    7 months later
    #1157 1 year ago
    Quoted from jejepinside:

    I try to repair my System 11 MPU board : I can't find new 102M capacitors 50V (M is for +-20% tolerance). This capacitor est located in C22 on the board for example.
    Alternatives found : 102K (+-10% tolerance), or 102M 250V.
    Are these alternatives any good ?

    Smaller tolerance or higher voltage rating is always fine
    Both can be used

    #1159 1 year ago
    Quoted from jejepinside:

    You don't think tolerance was desired by Williams? Example : to obtain 120 µF, a 100 µF capacitor is used with a tolerance of 20%.

    No it is not done like that
    The next part from the same patch could then only have as low as 80 uF and still meet the +-20% tolerance range
    If they wanted a 120uF cap (uncommon value though) they would have specd accordingly

    You're currently viewing posts by Pinsider harig.
    Click here to go back to viewing the entire thread.

    Reply

    Wanna join the discussion? Please sign in to reply to this topic.

    Hey there! Welcome to Pinside!

    Donate to Pinside

    Great to see you're enjoying Pinside! Did you know Pinside is able to run without any 3rd-party banners or ads, thanks to the support from our visitors? Please consider a donation to Pinside and get anext to your username to show for it! Or better yet, subscribe to Pinside+!


    This page was printed from https://pinside.com/pinball/forum/topic/dumbass-test-and-reproduction-pcbs?tu=harig and we tried optimising it for printing. Some page elements may have been deliberately hidden.

    Scan the QR code on the left to jump to the URL this document was printed from.