Dismantling the Micro-Nikkor 55mm f/2.8 Ai-S!

[richardHaw]

The proof that you can fit a Dandelion to the 50/1.2 AIS. Erik at his best

This method of attaching the Dandelion alleviates most if not all problems and weakness of the usual positioning, in which the chip will be exposed to excessive wear and tear. Still, the pins are on the long side so their tips will wear rapidly.

this looks fine but it's going to void the warranty of my 50 
do the contacts have to be protruding? how difficult is it to manufacture the chips at home? maybe i can find parts in akihabara and photoetch a board for that? (if it is indeed that easy)

[richardHaw]

Rick, sorry about your unfortunate experience with yahoo! auction, but the sense of emergency seems to have helped...

As for the aperture lever of 55/2.8, I heard that the two-piece aperture lever was replaced with the one-piece one because the two-piece version couldn't synchronize with the 10 fps continuous shooting mode of F2H.

i have now become wise and now know who are the dishonest people in Yahoo! auctions

i looked over all of my notes and it seems that all of the 55mm f/2.8's that I serviced all have 2 parts aperture lever...these are all early ones since they are usually the ones that need fixing and end up being sent to be or me finding them in the junk box. another weakness of this lens is the front cowl. it is easily bent and will prevent you from focusing.

[Hugh_3170]

Very nice work on Erik's part.  Well done both of you.

Bjørn, did you re-program the micro code in the Dandelion chip so that it now behaves like your own PCBs, or did you simply set those basic lens parameters that the Dandelion allows users to enter via the camera body?

I am guessing that some of the more subtle parameters such as exit pupil information that your PCBs have coded into them are less important for a 50mm lens. IIRC, the Dandelion is essentially a "G" type chip.

Would the spring loaded nature of the Dandelion pins help lessen the wear I wonder?

The proof that you can fit a Dandelion to the 50/1.2 AIS. Erik at his best

This method of attaching the Dandelion alleviates most if not all problems and weakness of the usual positioning, in which the chip will be exposed to excessive wear and tear. Still, the pins are on the long side so their tips will wear rapidly.

[Erik Lund]

this looks fine but it's going to void the warranty of my 50 
do the contacts have to be protruding?...

I have never heard of anybody ever needing to have warranty work done on a Nikon MF lens,,, 

The geometry and the position of the pins are given, they need to move to make a good solid contact with the contact surface on the camera, design and tolerances dictate this,,,

Good luck making your own CPU! 

Bjørn has several types of layout of the prints to accommodate for different mount designs.

[Erik Lund]

Very nice work on Erik's part.  Well done both of you.

Bjørn, did you re-program the micro code in the Dandelion chip so that it now behaves like your own PCBs, or did you simply set those basic lens parameters that the Dandelion allows users to enter via the camera body?

I am guessing that some of the more subtle parameters such as exit pupil information that your PCBs have coded into them are less important for a 50mm lens. IIRC, the Dandelion is essentially a "G" type chip.

Would the spring loaded nature of the Dandelion pins help lessen the wear I wonder?

You cant reprogram Dandelions, they are a stand alone product.

Yes no nodal point info.

I don't understand why there should be any wear on the pins?

The cut that one of the pins appears to have in the close up is most likely from my Dremel when cutting the Dandelion apart before the implantation into the mount.

[richardHaw]

I have never heard of anybody ever needing to have warranty work done on a Nikon MF lens,,, 

The geometry and the position of the pins are given, they need to move to make a good solid contact with the contact surface on the camera, design and tolerances dictate this,,,

Good luck making your own CPU! 

Bjørn has several types of layout of the prints to accommodate for different mount designs.

that was what i thought. until i got this one 
the optics was not up to par with the 50 1.2s that i have used and i insisted that nikon fix mine. after some pressure they finally swapped the internals with another one from the production line and i am currently very happy with my 50 1.2's results wide open

[Bjørn Rørslett]

Bjørn, did you re-program the micro code in the Dandelion chip so that it now behaves like your own PCBs, or did you simply set those basic lens parameters that the Dandelion allows users to enter via the camera body?
...

Would the spring loaded nature of the Dandelion pins help lessen the wear I wonder?

I just programmed the Dandelion of the 50/1.2 from the usual (and very awkward) camera-based interface. These chips are essentially "G"-type, the newer incarnations of which can be altered to "P" by additional user programming. However, conflicting reports of their ability to operate successfully in "P" mode are seen. Alarming reports of massive underexposure in "P" mode have been posted on the 'net.

Spring-loaded signal pins are a prerequisite for any CPU of an F-mount lens, otherwise you cannot safely attach the lens to the camera. However, the Dandelion spring-loading has extensive travel and the pins really stick out too far, so they grate on the camera-side contact surfaces. The pins of a Nikon contact block only travel a very short distance and the force they bring to bear onto the camera side is minute. Thus it is far more likely that Dandelion chips are subjected to excessive wear over time. The Dandelion of the 50/1.2, however, is seated deeper than normal for this kind of chip and the pins accordingly don't protrude more than with the standard contact blocks.

[Erik Lund]

....... that the design of the square holes with round pins poking through them wasn't ideal either. ........

.....Basically the square opening got so badly distorted, that it was no longer square(and thus only JUST) retaining the spring loaded pin.
The square openings were so badly distorted that the pins literally pushed out of their receptacles just enough so that they would bind against the camera body when being mounted/dismounted, which then distorted the dandelion body even more so, which added to the amount that the pin protruded ........

Sorry for snipping out, but I want to address design of the Dandelion;

The square holes you see are just the housing, they don't keep the pins/tubes in place.

The pins are held into position inside the small tubes you see inside the square.

The tubes are glued into position inside the housing together with the electronics.

Most likely there has been to little glue inside the housing to firmly hold onto the tubes in your Dandelion.

[richardHaw]

Sorry for snipping out, but I want to address design of the Dandelion;

The square holes you see are just the housing, they don't keep the pins/tubes in place.

The pins are held into position inside the small tubes you see inside the square.

The tubes are glued into position inside the housing together with the electronics.

Most likely there has been to little glue inside the housing to firmly hold onto the tubes in your Dandelion.

well, that sounds flimsy 

[Bjørn Rørslett]

The Dandelion didn't get its tainted reputation for no reason ....

[richardHaw]

OK, good news. looks like the chinese internet is full of OEM replacement parts for Nikon  (including contacts)

[Erik Lund]

There is a huge difference between Nikon 'plastic' and OEM 'plastic'  in some cases 

The plastic Nikon use is very flexible and tough - It is not brittle or hard in any way...

Nikon Pins are silver coated,,,

[stenrasmussen]

For a long time I've thought about a solution like this for the contacts in a chipped 50-58/1.2...
The red represents the new design with contact pins made of spring steel material. The orange bit is the CPU itself.

[Erik Lund]

I remember the ideas Sten

I even build a set of very similar contact pins, they where ripped off when I rotated the lens,,,

BTW this sectional view is not a Noct,,,

[stenrasmussen]

I remember the ideas Sten

I even build a set of very similar contact pins, they where ripped off when I rotated the lens,,,

BTW this sectional view is not a Noct,,,

There would have to be some sort of guide/slot to prevent the sideways movement when mounting the lens.
As for the diagram: Tis a composite of the Noct's barrel with the 50/1.2's lenses.