• Voltage Regulator on 36/38 Workstation Emulator

    From Louis Ohland@21:1/5 to All on Wed Nov 3 13:27:13 2021
    Looking at some 4224 Twinax cards and 5250 adapters and the 5494 Twinax adapter, they all use the LM2575T -5.0 voltage regulator.

    https://datasheet.octopart.com/LM2575T-5.0-NOPB-Texas-Instruments-datasheet-8191682.pdf

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  • From Tomas Slavotinek@21:1/5 to Louis Ohland on Thu Nov 4 11:21:16 2021
    On 3.11.2021 19:27, Louis Ohland wrote:
    Looking at some 4224 Twinax cards and 5250 adapters and the 5494 Twinax adapter, they all use the LM2575T -5.0 voltage regulator.

    https://datasheet.octopart.com/LM2575T-5.0-NOPB-Texas-Instruments-datasheet-8191682.pdf

    For the interface chip most likely...

    You won't find the regulator on the ISA cards as these can take the
    voltage directly from the bus connector/main power supply. MCA machines
    dropped the -5V PSU rail, so a local source is necessary.

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  • From Tomas Slavotinek@21:1/5 to Tomas Slavotinek on Thu Nov 4 11:44:46 2021
    LM2575 is a 5-lead switching regulator and requires large inductors/caps
    to operate - seen on the 5494 Twinax adapter. Both the short 5250
    adapter and the long S36/38 Workstation adapter use a 3-lead linear
    regulator (judging based on the photos). @David - can we get the part
    number?

    On 4.11.2021 11:21, Tomas Slavotinek wrote:
    On 3.11.2021 19:27, Louis Ohland wrote:
    Looking at some 4224 Twinax cards and 5250 adapters and the 5494
    Twinax adapter, they all use the LM2575T -5.0 voltage regulator.

    https://datasheet.octopart.com/LM2575T-5.0-NOPB-Texas-Instruments-datasheet-8191682.pdf


    For the interface chip most likely...

    You won't find the regulator on the ISA cards as these can take the
    voltage directly from the bus connector/main power supply. MCA machines dropped the -5V PSU rail, so a local source is necessary.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Louis Ohland@21:1/5 to Tomas Slavotinek on Thu Nov 4 10:54:33 2021
    Well, bless my eyes, the 36/38 DOES use a three lead VR.

    On 11/4/2021 05:44, Tomas Slavotinek wrote:
    LM2575 is a 5-lead switching regulator and requires large inductors/caps
    to operate - seen on the 5494 Twinax adapter. Both the short 5250
    adapter and the long S36/38 Workstation adapter use a 3-lead linear
    regulator (judging based on the photos). @David - can we get the part
    number?

    On 4.11.2021 11:21, Tomas Slavotinek wrote:
    On 3.11.2021 19:27, Louis Ohland wrote:
    Looking at some 4224 Twinax cards and 5250 adapters and the 5494
    Twinax adapter, they all use the LM2575T -5.0 voltage regulator.

    https://datasheet.octopart.com/LM2575T-5.0-NOPB-Texas-Instruments-datasheet-8191682.pdf



    For the interface chip most likely...

    You won't find the regulator on the ISA cards as these can take the
    voltage directly from the bus connector/main power supply. MCA
    machines dropped the -5V PSU rail, so a local source is necessary.


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    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From IBMMuseum@21:1/5 to All on Mon Nov 8 12:35:02 2021
    Both the short 5250 adapter and the long S36/38 Workstation
    adapter use a 3-lead linear regulator (judging based on the
    photos). @David - can we get the part number?

    Sorry, I must have been dozing - Not any easier by them inverting that component on both adapters, but it is a standard [UA]7905[C] for -5VDC as expected.

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  • From Louis Ohland@21:1/5 to IBMMuseum on Mon Nov 8 18:13:27 2021
    https://datasheet.datasheetarchive.com/originals/distributors/Datasheets-36/DSA-717469.pdf


    On 11/8/2021 14:35, IBMMuseum wrote:
    Both the short 5250 adapter and the long S36/38 Workstation
    adapter use a 3-lead linear regulator (judging based on the
    photos). @David - can we get the part number?

    Sorry, I must have been dozing - Not any easier by them inverting that component on both adapters, but it is a standard [UA]7905[C] for -5VDC as expected.


    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Louis Ohland@21:1/5 to Tomas Slavotinek on Tue Nov 9 09:45:32 2021
    So, we have documentation of the bit stream, the protocols, but I'm not
    seeing any circuit-level stuff.

    Could an adapter capable of SDLC do 5250 / 3270 / 36/38 communications?


    On 11/9/2021 09:39, Tomas Slavotinek wrote:
    Thanks for confirmation. Pages updatedtdtdtdt...dt.

    On 9.11.2021 1:13, Louis Ohland wrote:
    https://datasheet.datasheetarchive.com/originals/distributors/Datasheets-36/DSA-717469.pdf



    On 11/8/2021 14:35, IBMMuseum wrote:
    Both the short 5250 adapter and the long S36/38 Workstation
    adapter use a 3-lead linear regulator (judging based on the
    photos). @David - can we get the part number?

    Sorry, I must have been dozing - Not any easier by them inverting
    that component on both adapters, but it is a standard [UA]7905[C] for
    -5VDC as expected.



    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Tomas Slavotinek@21:1/5 to Louis Ohland on Tue Nov 9 16:39:48 2021
    Thanks for confirmation. Pages updatedtdtdtdt...dt.

    On 9.11.2021 1:13, Louis Ohland wrote:
    https://datasheet.datasheetarchive.com/originals/distributors/Datasheets-36/DSA-717469.pdf



    On 11/8/2021 14:35, IBMMuseum wrote:
    Both the short 5250 adapter and the long S36/38 Workstation
    adapter use a 3-lead linear regulator (judging based on the
    photos). @David - can we get the part number?

    Sorry, I must have been dozing - Not any easier by them inverting that
    component on both adapters, but it is a standard [UA]7905[C] for -5VDC
    as expected.


    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From IBMMuseum@21:1/5 to All on Tue Nov 9 08:13:37 2021
    So, we have documentation of the bit stream, the protocols,
    but I'm not seeing any circuit-level stuff. Could an adapter
    capable of SDLC do 5250 / 3270 / 36/38 communications?

    The "Remote 5250 Emulation Program" communicates with a mid-range host with an SLDC adapter (or in the case of a microchannel system, the Multi-Protocol Adapter/A") - emulating the terminal and 5294/5394/5494 link. The 3270 stuff will come in time, I'm
    focusing on the mid-range level right now because I have an available host. Do you remember any content on the Multi-Protocol Adapter/A before? - there may be some EC notes on whether a 'ZM1' chip is present or removed on the adapter.

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