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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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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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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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.

--- SoupGate-Win32 v1.05
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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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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
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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)

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)

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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