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Tinkerer
Username: Mike_kovacs
Post Number: 13
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, November 20, 2007 - 07:27 pm: | 
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OK not exactly a classic but certainly a cult classic.
I've got one with fungus behind the 2nd element from the front. The 1st element came out easy - set screw, unscrew retaining ring but where from here?
How to get helical apart. I'm pretty sure the rear of #2 is accessible with the helical disassembled. The zooming elements are in the back. |
Ethostech
Tinkerer
Username: Ethostech
Post Number: 83
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, December 22, 2007 - 05:54 am: |
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Mike ... The Series E Nikkor is often disaparaged as a budget range but the fact is the Series E 75 - 150 Zom is one of the best Nikkor lenses ever made.
Here are some notes from my archive:
Quote:
Nikon (Series E) ƒ3.5 75 -150mm Zoom. Service Notes. 24.01.05
Lens came to me together with the F301 as an eBay win.
Lens cosmetically flawless but the zoom ring fell like a brick under its own weight an the focusing ring too was as loose as a bag of bones. Both clearly required grease-damping.
Some notes here first on the construction.
Tomasy gives a dozen only lines in his Book 2 - as follows:
Remove the rubber grip from the focusing barrel and then remove the three screws beneath at the trailing edge of the barrel. Peel off the brass shim guard to reveal the brass focusing slider. When the slider is removed (one screw) the front lens group can then be unscrewed from its helix together with the focusing barrel. One can then access the helical zoom sliders.
I did in fact strip to the above extent but I think I could have done the grease damping simply by removing the two element front lens group as a module. This is the module which is used to focus the lens and it is locked by a single set-screw. W ith the module removed we can access the focusing helix, clean it and grease it.
We can also see the two "straight" zoom-guide carrier slots which can be liberally packed with grease and the zoom exercised between grease applications until required stiffness is achieved. When both the focusing helix and the zoom-guide slider slots have been greased in the above way, thoroughly exercise and then carefully clean off any surplus "ooze" grease with a cotton-bud. Remove any grease marks with a cotton but as slightly moistened with Shellite. (pretroleumspirit). Now simply screw in the front doublet focusing module, estabish the infinity position (through the viewfinder picture) and lock up the set screw.
I however followed Tomasy and made more work of the job than was necessary.
The difficulty was getting the correct start on the focusing helix.
It occurs that with the outer focusing barrel at the Infinity position, the helix must be started so that the screw-hole for the brass slider coincides with the slot in the outer focusing barrel. I had quite a fiddle and several attempts before I got the helix start right - even though I had placed a reference mark on a piece of tape (as stuck to the rotating barrel of the helix) to indicate a pre-dissassembly straight line coincident with the focusing barrel Infinity mark.
The key point is that the outer barrel Infinity mark and the brass slider slot have a fixed relationship in that they are machined as part of the barrel design. If the helix is wrongly started we can still end up with the lens correctly resolving infinity and the lens barrel also at infiniity BUT the slider screw hole is nowhere to be seen.
Special note:
There is a large brass distance-piece washer beneath the focusing doublet module.
When after this service I came to fine-tune the focus at infinity I started by fully screwing in the module against the washer. This brass ring was probably selected for gauge from various optional thickness of factory inventory in order that Infinity would resolve with the module screwed hard against it. If it were even slightly thin, it would rattle.
Upon focusing the front group module I found it necessary to slighly unscrew it in order to achieve absolutely precise focus. And this indeed caused brass ring to rattle. Therefore I gummed the brass ring hard against a piece of photocopy paper - and when the gum was dry, profiled the paper. In this way I had increased the thickness of the ring by 0.004" - which was just enough to facilitate screwing the module hard down and produce "spot-on" focus.
Hope yo find this helpful.
Stuart Willis |
