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Anyone has model F 122 key PCB laying around?
Posted: 23 Jun 2016, 07:52
by DMA
Need good photos of both sides and closeups of connector - also both sides.
I do have the 122key model F - but I'm afraid I'll spend like 2 days assembling it back. Not mentioning all the foam crumbs!
Need it to decide how to better lay the ground out on my prospective controller.
If this is the wrong forum for that - dear admins, please move it to a correct one.
Posted: 23 Jun 2016, 12:37
by andrewjoy
From my experience with replacement model F controllers your controller should be grounded to the case ( plate) as well as the PCB .
Posted: 23 Jun 2016, 14:45
by fohat
The controller screws onto the plate at both ends so that probably takes care of it.
There may be some helpful photos here:
workshop-f7/ibm-model-f-122-key-termina ... ansi%20122
Posted: 23 Jun 2016, 17:47
by DMA
andrewjoy wrote: From my experience with replacement model F controllers your controller should be grounded to the case ( plate) as well as the PCB .
That goes without saying.
Basically, I'm trying to figure out what path the majority of return current will take, and will those paths be different for driving part and for sensing part or not. This will profoundly affect the wiring.
Posted: 17 Jul 2016, 05:18
by lot_lizard
I should have several F122's with the Cindy switch haul on the Model MF project. Would you like me to send you a PCB to test with?
Posted: 17 Jul 2016, 05:30
by DMA
lot_lizard wrote: I should have several F122's with the Cindy switch haul on the Model MF project. Would you like me to send you a PCB to test with?
wcass already sent me all the photos I need, thanks
Also I bit the bullet and disassembled mine already. Even managed to assemble it back today - ANSIfied it along the way

Posted: 17 Jul 2016, 09:04
by alh84001
I was kind of intimidated by disassembling mine, but I had to do it (one column was not working). When it came to putting it all back, it was one of the more simple steps in the end. And I did it with no tools, just pressing and sliding it. I do't know if it's the same with XT/AT and others, but that was really not a boogeyman it was made out to be

Posted: 17 Jul 2016, 09:50
by lot_lizard
alh84001 wrote: When it came to putting it all back, it was one of the more simple steps in the end. And I did it with no tools, just pressing and sliding it. I do't know if it's the same with XT/AT and others, but that was really not a boogeyman it was made out to be

Can you crack walnuts with your bare ape hands too?!?
Playing, and I agree. I just use my hands as well. Too much tension and it won't slide, easier to finesse a stubborn tab, etc. The boards with more rows are easier though since it is taller and the plate is still the same thickness (bends easier). The 4704 is the toughest I think.
Only caveat is if you replaced the foam. The old foam is pre-compressed, and helps the process a little.
Posted: 17 Jul 2016, 10:26
by alh84001
Actually no. Among my friends I am often singled out as that guy with hand-model hands
But back on topic, the foam in mine was the original, and I kind of expected the taller plate to be easier to work with. I'll be assembling an XT with replacement foam soon, so we'll see how I fare then

Posted: 17 Jul 2016, 14:55
by fohat
Old foam makes the problem mostly go away, but I think that the additional tension from a robust foam makes a significant difference in feel. I did several XTs and ATs with old foam with bare hands before I started on 122s.
Also, every board is different. Of roughly a dozen 122s that I have done, there were a couple that were particularly easy and a couple that were particularly difficult, including one that was an absolute nightmare.
It must be a function of the curvature of the plates and how much they are "sprung"
Posted: 18 Jul 2016, 13:15
by andrewjoy
DMA wrote: lot_lizard wrote: I should have several F122's with the Cindy switch haul on the Model MF project. Would you like me to send you a PCB to test with?
wcass already sent me all the photos I need, thanks
Also I bit the bullet and disassembled mine already. Even managed to assemble it back today - ANSIfied it along the way

Did you put the spring for the ANSI return and backspace in the right place

, i have done 3 model F ansi conversions now and i always do it wrong

Posted: 18 Jul 2016, 15:02
by fohat
andrewjoy wrote:
i have done 3 model F ansi conversions now and i always do it wrong.
Ha Ha Ha. I have done a dozen and I still make a spring mistake at least half the time. Usually I am just merrily dropping springs in place without thinking and put in too many, rather than too few.
Posted: 18 Jul 2016, 16:56
by DMA
andrewjoy wrote:
Did you put the spring for the ANSI return and backspace in the right place

, i have done 3 model F ansi conversions now and i always do it wrong

Yep!
But I managed to put two springs to the numpad zero. Not a big deal - just used the original key
