Bolt modding IBM/Lexmark 42H1292 ( Need help removing controller board)

[bazemk1979]

All went smooth, actually fast due to the fact my first bolt mod, took care of rivets in 15 min.... put a smile on my face until I started removing layers and saw that the controller board is weirdly attached or whatever, not sure how to remove it. If its a risky business I might have to do the drilling and rest around it with the first sheet on it. Don't want to do it this way, but how stupid Lexmark were placing the controller like this?

Here are few pics, if any one has an idea, this gets done tonight the hard or the easy way, reaching out for the easy way

[bazemk1979]

NVM figured it out, curious who is the designer behind this one...... idiot

[fohat.digs]

Those layers do not want to come apart at first because the cut rivets are not perfect cylinders and still have hooks and burrs on top that want to keep the membranes down.

After you give them a nice flat top haircut (above the crescents, remember) getting the sheets on and off will be easy in the future.

[The_Ed]

It should be pointed out that old IBM manufactured Model M membranes are GLUED to the plate. So not all membranes are removable.

[bazemk1979]

don't know what you people talking about, glued not glued, whatever.

You guys don't read what I wrote, its not the membranes I had problem wit..... It was the damn controller was totally differently positioned than on the IBM made Model M's. the only contact between the membrane and the controller was both part pressing on each other between the inner plastic that had some clips and spong cut out to protect the membrane from scratching.

I have never seen Model M with glued down membranes..... maeby Unicomp?

[fohat.digs]

You guys don't read what I wrote, its not the membranes I had problem with. It was the damn controller was totally differently positioned than on the IBM made Model M's. the only contact between the membrane and the controller was both part pressing on each other between the inner plastic that had some clips and sponge cut out to protect the membrane from scratching.

I have bought a couple of cheap 42Hs and neither worked. The plates are light so I harvested parts and tossed the chassis. I never really studied the controller but assumed that was the problem.

Seriously doubt that they ever glued down membranes at the factory. Undoubtedly that happened later with soda or beer.

[bazemk1979]

the controller took some time playing around until I removed it, the rest was easy except the last part torqueing the nuts and bolts, got hang out of that one.... took me long time to figure out not every screw had to be tight equal....

[fohat.digs]

not every screw had to be tight equal ....

One advantage of the bolt mod is the ability to adjust.

Once I had a cluster area of about 4 screws that wanted to be much looser than the others.

[bazemk1979]

for me the problem was the enter key on the number pad, was clicking great but since I over tight that area the spacer that goes into the barrel with the with the white pad was getting stuck. turned out I had to loosen up the whole board in the middle and then the rest little by little so it can stretch and free up the ends a bit and came to its previous factory spherical form

Honestly this board had zero need for bolt mod   was only missing 1 or 2 rivets, but since was my first board and thinking if something happens I rather to happen on the 42H1292 model, the least popular one.

[The_Ed]

don't know what you people talking about, glued not glued, whatever.

I have never seen Model M with glued down membranes..... maeby Unicomp?

Seriously doubt that they ever glued down membranes at the factory. Undoubtedly that happened later with soda or beer.

Neither of you read what I said... I said:

It should be pointed out that old IBM manufactured Model M membranes are GLUED to the plate. So not all membranes are removable.

The first few years they glued them down. But that doesn't necessarily apply to all of them from the first few years. I just made that comment so that if you later bolt modded an old one you wouldn't wreck the membrane by trying to tear it off.

[bazemk1979]

don't know what you people talking about, glued not glued, whatever.

I have never seen Model M with glued down membranes..... maeby Unicomp?

Seriously doubt that they ever glued down membranes at the factory. Undoubtedly that happened later with soda or beer.

Neither of you read what I said... I said:

It should be pointed out that old IBM manufactured Model M membranes are GLUED to the plate. So not all membranes are removable.

The first few years they glued them down. But that doesn't necessarily apply to all of them from the first few years. I just made that comment so that if you later bolt modded an old one you wouldn't wreck the membrane by trying to tear it off.

Hmmmm, how early are we speaking of those IBM model M's were with glued down membranes? cause I have one square metal logo without the LED's that badly needs bolt mod + comes in the original box

What would be the take on when bolting IBM with glued membranes on the metal plate. So they need to be peeled off slowly or you just prep the plastic barrel insert bolts and place the whole piece ( metal plate + glued membranes) on top of it carefully? or you need to peel off the membranes from the metal plates. Not sure how many membranes the old IBM had, this one had the padding, then a membrane with traces, then a blank membrane and then another membrane with trace.

[fohat.digs]

Terminology is tricky here.

As I remember - there are about 3 sheets of clear mylar, some printed, some not, which I would call the "membranes" although maybe that is not how everyone says it.

Then there is a rubber mat ("blanket" in Unicomp terminology) that lays directly on the metal back plate to keep the mylar sheets off. The old ones were black rubber, much like a bicycle inner tube but only about 1/3 as thick. The new ones that Unicomp is selling (I recently bought one and installed it in my 1986) are very thin white latex, just about like a surgical glove you see at the doctor's office.

[bazemk1979]

Lexmark blanket was pretty thick, working on the square metal logo now and curious if the membranes on this ones are glued which I really doubt, and this one is made Nov 1986.... 70% of the rivets are gone, but still clicks sharp and snappy. Oh and it has the shiny plate

[bazemk1979]

damn this 1390120 has the last layer glued down, not glued too strong but I rather work around it then risking to peel it off and brake some traces,  its should be workable just fine with 1 layer glued on the metal plate

[fohat.digs]

Lexmark blanket was pretty thick, working on the square metal logo now and curious if the membranes on this ones are glued which I really doubt, and this one is made Nov 1986.... 70% of the rivets are gone, but still clicks sharp and snappy. Oh and it has the shiny plate

My pride and joy is a December 1986 1390131 with gold plate. I did a full bolt mod, although, amazingly, when I opened if for the first time (a couple of years ago) there was  NOT  ONE  broken rivet!

It now has 2010 Unicomp springs and a brand new white Unicomp blanket. This last time I tightened the nuts a little harder than usual.

[bazemk1979]

well bolts are in but the plastic barrel plate is of the old style..... no bridges sticking out between the barrels, something tells me it will snap when I try to tighten the nuts but we will see, if it does going to have to order new plastic plate from Uni. Btw do Unicomp plastic plates come with the the plastic lips for the stabilizers that are on + and Enter key at the numberpad? if not I guess I will have to order 2 more barrel insert if I cant use the stabilizers.

[dorkvader]

about the glued down membranes, I ran into that with my 1390200 (march 3 1985, barcode label, special crystal and all) when I bolt modded it. The membranes came off with the plate, no issues. I think they might only be glued at the edges, and I didn't try removing them, but it didn't cause any issue.

[neoezekiel]

I just ran into a glued membrane on an 86' M 122 key.
Having one hell of a time bold modding this sucker.
I am looking for different springs to put on the hammers since my old source for super stiff springs has dried up.

Anyone have any suggestions for sourcing stiffer springs than Unicomp or good bolts? (need a new supplier for these too )

[bazemk1979]

I just ran into a glued membrane on an 86' M 122 key.
Having one hell of a time bold modding this sucker.
I am looking for different springs to put on the hammers since my old source for super stiff springs has dried up.

Anyone have any suggestions for sourcing stiffer springs than Unicomp or good bolts? (need a new supplier for these too )

FYI the late models that have thick plate can be tricky when torqueing the bolts. The tenkeypad is really heavy to torque and maeby ull hear people saying don't drive the nuts close to the stabilizers or you wont be able to use to stabilizers...

Truth is if you don't do this, the enter and + keys will stick even if you use the later keys without modifiers and the barrel sliders for them. Torqueing the tenkeypad is a tricky business and make sure you trow bolts and nuts in there..... you don't even need the stabilizers, the enter and + keys stay pretty straight without the stabilizers.

You cant torque this plates because the nuts cant hold the pressure and they will strip off, I learned the hard way by going back and forth and finally gave up, this is not a problem with the later oval logo models, the plate is thinner and you can torque the tenkey pad much easier. Just giving you heads up so you save your self from hours of cratching your head why it don't work, that plate is a beast and if you don't torques the plastic barrel plate correct to the metal plate, the + and enter keys from the tenkeypad will stick and nothing you can do if you don't drive bolts in that area.

Here are the parts you need:

http://www.mcmaster.com/#catalog/119/3019/=nken1q

http://www.mcmaster.com/#catalog/119/3167/=nkeqi6

BTW most likely you don't need new springs, but from my opinion Unicomp only makes the springs and they feel snappier than a brand new Model M, Unicomp springs feel better in general vs Model M springs.

[Tarzan]

What size bolts do you guys recommend for a Model M bolt mod?  I did one with bolts/nuts from Home Depot, just picked a lot of different sizes until I found some that worked.  Anyone know the stock thickness of the cover plate/membrane/metal plate sandwich?

[fohat.digs]

What size bolts do you guys recommend for a Model M bolt mod?

If you read Sandy's Bolt Mod, which is probably still the reference standard, he shows you how to do it.

I always used tiny bolts to preserve the "crescent" stand-offs.

These come in packs of 100 which is perfect because 1 board takes about 50.