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Thread: Help with 8 inch floppy YE-DATA YD-174D

  1. #11

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    Hello everyone

    First of all, thank you for your suggestions.

    I put the link to the manual of the YD-174 but my YD-174D-1222D does not have the same options and I have not found a good manual.

    The YD-174 is the same as the QUME-842 http://bitsavers.informatik.uni-stut...2svc_Dec81.pdf

    On page 22 you can see that it is not the same pcb.

    20210116_092445.jpg pcb.jpg

    I have made the 50 to 34 pin adapter but it not work. why?

    20210303_142500.jpg 20210303_142531.jpg

    After analyzing the connector on the pcb I have seen that it is not the standard.

    Standard

    50 pin std.jpg

    PCB

    20210303_172036.jpg

    I'm not sure if the first pin is right or left

    Now I have to invert the pins of the protoboard and see what happens ...
    Last edited by Fran; March 3rd, 2021 at 08:21 AM.

  2. #12
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    The easiest test would be take your 8" floppy Drive and check Pin 26 of the 50 Pin connector.
    It will go to the DS1 Jumper for Drive Select. That way you know 100% you are on the correct
    Pin, and this will allow you to interface from this point to the remaining pins.

    Larry

  3. #13

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    Quote Originally Posted by ldkraemer View Post
    The easiest test would be take your 8" floppy Drive and check Pin 26 of the 50 Pin connector.
    It will go to the DS1 Jumper for Drive Select. That way you know 100% you are on the correct
    Pin, and this will allow you to interface from this point to the remaining pins.

    Larry
    ds.jpg ds2.jpg

  4. #14
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    It looks to me like your Photo on the Right (PCB) is numbered as follows.
    The Pin you have as 1 is really 2, as 1 3, 5 are GND. Pin 7 has no Pin in the connector
    to match your ribbon cable. I've relabeled a previous Photo you posted to mark the
    Pins as they appear to be laid out. You can use Pin 26 in the 50 Pin connector to chase it to
    one of the Vertical pins for selecting DS1, just to VERIFY my marked up Photo is correct.

    Please OHM out Pin 26 of 50 Pin connector to the DS{1..4} Pins, to make sure.

    Larry

    floppy8.jpg

  5. #15

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    Pin 26 is not directly connected to DS1, it connects to pin 10 of the SN7414N and pin 13 of the SN7414N connects to DS0, DS1, DS2 and DS3

    floppy8.jpg

    20210303_215450 2.jpg

    Assuming pins 1 and 2 are on the left I have reversed the 50 pin connector on the pcb and I have connected the protoboard to the Kyroflux, head load works but not step.

    20210303_231628.jpg

    Last edited by Fran; March 3rd, 2021 at 02:07 PM.

  6. #16
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    From your Photo #2 in the last post I see you added some red jumpers trying to get the signals to the
    correct place. Rather than doing that what we need is a Schematic and a Technical Manual that shows
    what the various jumpers do and figure out what is needed for the Kryoflux.

    If we can get a schematic that details the jumper selections it shouldn't be too hard.

    I can't find any information on the 8 pins marked as "S" & "R" and are associated with the Drive
    Select lines. That's likely the information we need, but locating it isn't going to be easy.

    Larry

  7. #17
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    How about posting closeup photo's of top left Pins and text on PCB, bottom left pins and text on PCB.
    And close up photo of the PADS 0, 1, 2, 3 with "S" & "R" text on PCB?

    Thanks.

    Larry

  8. #18

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    Quote Originally Posted by ldkraemer View Post
    From your Photo #2 in the last post I see you added some red jumpers trying to get the signals to the
    correct place. Rather than doing that what we need is a Schematic and a Technical Manual that shows
    what the various jumpers do and figure out what is needed for the Kryoflux.
    They are not red jumpers, they are lines drawn with paint.

    Quote Originally Posted by ldkraemer View Post
    How about posting closeup photo's of top left Pins and text on PCB, bottom left pins and text on PCB.
    The photos are in the first post I published

  9. #19
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    Fran,
    Sorry I missed those pictures of the jumpers in the corners of the PCB. And I assumed the red Lines were added Jumpers.
    Thanks for clearing that up.

    It has been years since I used the Kryoflux, so I downloaded the manual, and had a look at it. The Kryoflux is designed
    to use the PC Twisted cable (conductors 10 thru 16 twisted) and Drive 0 will be at the end of cable.....But, it will need to
    be strapped as DS1 in the DS{0..3} configuration. In your case with the DS Markings being DS{1..4}, you will need
    the DS Jumper on DS2 (Pin 28). The twisted Cable conductors will take care of routing the proper signals to the drive.

    You need to make sure the Kryoflux is set for one Floppy Drive, and I would suggest adding the Kryoflux Write Blocker
    Jumper. This will protect the floppy's data from accidentally being over written.

    Try strapping both your Blue Jumpers to DS2 on the 8" Drive and connect the floppy cable with the Twisted Conductors
    10 thru 16 from the Kryoflux to the FDADAP Board, then the 50 Pin cable to the 8" Floppy Drive.

    Your Interconnect should be from Kryoflux Cable End (PC) to 8" Floppy Drive:
    Code:
    PC(34p)   8"(50p)    Description
    
             >   2       TG43
         8   <  20       Index
    
                                  0   1   2      3
    A:  (For 8" DS{1..4} use Pin 26, 28, 30, or 32)
        14   >  28       DS0(PC) -> DS2(8")
        10   >  18       Motor ON/Head Load A:
    
                                  0   1   2      3
    B:  (For 8" DS{1..4} use Pin 26, 28, 30, or 32)
        12   >  28       DS1(PC) -> DS2(8")
        16   >  18       Motor ON/Head Load B:
    
        18   >  34       Direction
        20   >  36       Step
        22   >  38       Write Data
        24   >  40       Write Gate
        26   <  42       Track 0 detect       All Odd numbered
        28   <  44       Write Protect        pins are GROUND
        30   <  46       Read Data
        32   >  14       Side1 Select
        34   <  12       Disk Change
    So, remove the cable from the Kryoflux and OHM from Kryoflux End of Cable (Pin 14) to see if it goes to
    the 8" floppy's Pin 28 (DS2) which is the same as DS1 for the PC's end.

    Likewise, Pin 10 of the Kryoflux Cable end should terminate on the 8" floppy's Pin 18 for Motor ON.


    Larry
    Last edited by ldkraemer; March 4th, 2021 at 03:01 AM. Reason: typo

  10. #20

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    Hi

    After many hours of testing without any results I decided to check the pins on the cpu pcb

    It is not a standard Shugart connector

    The FDC is a NEC D765AC https://www.alldatasheet.com/datashe.../NEC/D765.html

    Trying to understand the pin assignments on the 50-pin IDC connector I followed the PCB traces

    FDD.jpg

    50 pin IDC connector.jpg

    I need help to assign the pins correctly, I have many doubts

    Traces

    PCB traces.jpg

    High resolution https://www.conectaconsultores.es/sanco/PCBtraces.jpg

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