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

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.

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.

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.
>

> 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.

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.
>

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.
>>

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.
>>>
>

> 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.

Searched for Multi-Protocol and MultiProtocol, only issues so far is
using the wrong I/O location. Nothing hardware. Yet.

On 11/9/2021 10:13, IBMMuseum wrote:
>> 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.
>