Identifying which buckling spring switch

[ihasmario]

Are there any guides out there to discern whether a board is using a Model M style switch or a Model F style switch?

Picture related.
I posted a recording over here
https://app.box.com/s/17utmz76zh9qh0agquln It sounds very metallic and many of the keys "ring".

There's no mention of how to  service the keyboard in the manual. I could try and dismantle it, but I could damage some of the ribbon cables in the process, which I do not want to do.

Thanks

Edit; the board has a metal plate under the PCB (exposed) and is stamped 1984. This is a wheelwriter 5 (specifically a 6747).

[ch_123]

The Wheelwriters used membrane buckling spring keyboards (they were in fact the first IBM product to do so)

Differences in sound can largely be explained by the construction of the keyboard, both in terms of the fact that it is mounted inside a typewriter instead of plastic shell, and also that it's rather old (they all sounded slightly different over the years) I also seem to recall that the Wheelwriter keyboards have some sort of dampers on them which may affect their noise vs. a regular Model M.

To answer your question more directly - the most straight forward way to check is to remove some keycaps and look at the top of the keyboard assembly (sometimes called the barrel plate). If it's all plastic, it's an M. If it's metal with plastic barrels, it's an F. If the backplate is attached to the barrel plate with plastic rivets, it's an M. If they slot together at the top and bottom with metal tabs, it's an F. The presence of a ribbon cable also suggests an M, I think every Model F assembly I've seen had the controller permanently attached to the assembly with a non-removable flat cable.

EDIT: There were a few obscure Model M variants which used a Model F style assembly, so the presence of a plastic ribbon cable instead of a flat cable is probably the most reliable indicator.

There's no mention of how to  service the keyboard in the manual. I could try and dismantle it, but I could damage some of the ribbon cables in the process, which I do not want to do.

With both the Model M and Model F, you were not intended to dismantle the keyboard assembly, instead you'd toss it and buy a new one if there was something wrong with it. In the case of the M, it is simply not designed to be opened. For the F, IBM seemed to believe that there was too much risk of contamination interfering with the capacitive sensor card.

[ihasmario]

Thanks.

Since you seem to be relatively knowledgeable about wheelwriters...

Do you know the pinout of the 7 pin option port at the back, that was used to connect things like printers and displays, and what kind of information can be sent/received through this? I would like to run the wheelwriter as a terminal display/telewriter, or alternatively as a method of mirrored input (i.e. what the wheelwriter produces is produced on an external computer).

Thanks.


EDIT: Also, yes the board does have O-ring style dampers on the keys, which I am in the process of removing.
EDIT:: The backplate is attached with plastic rivets, has single piece keycaps, a transparent plastic flat cable with visible traces, the barrelplate is all plastic. I guess the logical conclusion is that it is a model M, which is odd, because it's the only model M I prefer to my 5576 and the only one with stronger springs.