The Sinclair QL Forum

Posted: **Sat Nov 11, 2023 5:52 pm**

Pr0f wrote: ↑Sat Oct 28, 2023 3:49 pm I confirm the Tetroid T1 board does work

Do you happen to know what are the main differences in T1 and T2 compared to ISS6?

Does T1 still mainly use the original tracks and components layout, or was it entirely redone?

Posted: **Sat Nov 11, 2023 6:16 pm**

M68008 wrote: ↑Sat Nov 11, 2023 5:52 pm Do you happen to know what are the main differences in T1 and T2 compared to ISS6?

Does T1 still mainly use the original tracks and components layout, or was it entirely redone?

Never mind, I eventually found the info here: http://www.qlforum.co.uk/viewtopic.php?t=3048

Posted: **Sat Nov 11, 2023 11:09 pm**

As you've found - most of the changes are documented there - the reset switch is no longer the 2 part switch used by the original QL, but takes a standard footprint momentary switch with 6 pad layout.

Posted: **Fri Nov 17, 2023 8:19 pm**

Checking out what components left for my repro Tetroid Iss6 in service manual...
L3 & L5 have not reference at all on it.
Only in the Schema. Based on Schema:
L5 = 22uH
L3 = 22uH

But... no idea what other electrical or any other attb they should keep.

Posted: **Sat Nov 18, 2023 8:45 am**

L5 needs to be a large 1 or 2 W inductor as it's in the 9v feed for the Microdrives and is there to prevent noise being passed through the supply. It should be rated for at least 1 Amp

L3 can be a lower power - 1/4 W inductor - it's used in the PAL video encoder chip circuit.

Both components should be axial types with leads.

Posted: **Sat Nov 18, 2023 10:16 am**

Pr0f wrote: ↑Sat Nov 18, 2023 8:45 am L5 needs to be a large 1 or 2 W inductor as it's in the 9v feed for the Microdrives and is there to prevent noise being passed through the supply. It should be rated for at least 1 Amp

L3 can be a lower power - 1/4 W inductor - it's used in the PAL video encoder chip circuit.

Both components should be axial types with leads.

Thank you

The share the same footprint so ... I will put same type, and at least 1W (perhaps 2W if it is not too big)

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