Nikon F3 and special models: Care, service and repair

[Andreas Thaler]

Now I'm going to look at the F3 pin registration, but after a quick test it should be OK.

I'm excited to see if I can find out how it works on the adapted MD-4, the box on the back of the F3 also has electronics with LEDs built in.

 

[Andreas Thaler]

Nikon F3 Pin Registration



I can't say much more about this modified Nikon F3 than I have already said in this post.

Post in thread 'Collection of spare parts for Nikon F3 and F3/T including a F3 Pin Registration'
https://www.photrio.com/forum/threa...ing-a-f3-pin-registration.203101/post-2743547


It is an F3HP with a modified film guide and a special back door that is connected to the MD-4 Motor Drive via a cable.

It was probably used for montage of shots.

The focusing screen is interesting, as it has markings for the alignment of templates:

The camera works, with a standard back it could be used for normal photography, the focusing screen can be changed.

The F3 pin registration is rare and certainly of interest to collectors.

I might sell it, it doesn't appeal to me.

 

[mshchem]

The F3AF and lenses are still beautiful. Is it responsive in Aperture priority mode? ie is the electronic shutter responding rationality? Even if the display is crazy if the shutter is still making good exposures

 

[Andreas Thaler]

The F3AF and lenses are still beautiful. Is it responsive in Aperture priority mode? ie is the electronic shutter responding rationality? Even if the display is crazy if the shutter is still making good exposures

Yeah! Everything works except the display.

 

[Andreas Thaler]

The F3AF and lenses are still beautiful. Is it responsive in Aperture priority mode? ie is the electronic shutter responding rationality? Even if the display is crazy if the shutter is still making good exposures

The 200 mm tele is an ED.

 

[Andreas Thaler]

View attachment 369002

In the viewfinder I see a nasty surprise that remains even after removing the DX-1: The LCD display is faulty.


View attachment 369004

I'm prepared for this eventuality, I've just added two F3 LCDs to the spare parts inventory.

Replacing the display should solve the problem.


View attachment 368996

To do this, I remove the replacement LCD from its holder.


View attachment 369003

Working with magnifying glasses.


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The replacement LCD is inserted and secured with its cover plate.

But unfortunately this LCD also shows the faulty digits from before.

So it can only be the circuit.


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I find a suitable error pattern in the repair manual and follow the troubleshooting instructions.

I use the oscilloscope to measure the voltage curve at the LCD contacts in the camera.


View attachment 369001

The measuring point is the first contact in the top row.

The rectangle curve displayed on the oscilloscope corresponds to the specification.

According to the repair manual, the LCD is still defective - but that is ruled out after the replacement.

And the circuit board that carries the contacts.

But I can't find any fault here.

I can't do anything else, so I'm reassembling the F3AF.

Very sad, because the camera works without the LCD, but in aperture priority mode A you can't see which shutter speeds are running. Exposure adjustment is also not possible in manual mode M.

But I'll keep looking in the repair manual to see if I can find any more information that can help.


View attachment 369005

View attachment 368998

Since I had closed the backdoor after removing the rewind crank and the lock cannot be released, I open the backdoor as an emergency measure

To do this, I unscrew the FRE (Functional Resistance Element), which records the aperture setting, the ASA value and the exposure compensation, and lift the hook of the lock.


View attachment 369000

Not a pleasant day today.

But even electronics are powerless against the ravages of time

In the repair manual I saw some error patterns for the LED that could be relevant.

To further investigate I will look for the corresponding checking lands (measurement points) and certain soldering points on the flexible circuit board.

It's good that I already have disassembled F3 housings for study.

If I have to remove the front panel to do this, I'll give up. I recently had problems assembling the F3P.

 

[Andreas Thaler]

In the repair manual I saw some error patterns for the LED that could be relevant.

To further investigate I will look for the corresponding checking lands (measurement points) and certain soldering points on the flexible circuit board.

It's good that I already have disassembled F3 housings for study.

If I have to remove the front panel to do this, I'll give up. I recently had problems assembling the F3P.

In the Nikon F3 repair manual under Troubleshooting, a similar LCD error pattern to my F3AF is listed with information on where to look on the FPC (flexible print circuit) to check for separation of a solder connection.

The location is on the back of this part of the board.

Here is the exact position on the back.


To get there, the following will be necessary:

1. dismantling the two top covers including the assembly with the FRE (functional resistance element) on the left side,
2. dismanling the LCD housing above the mirror box,
3. removing the front panel,
4. loosening the FPC in the marked area to be able to see the back.

I don't know if I should do it.

I don't see any problem if the process works as I imagine.

But I had problems with the coupling of the mirror and shutter mechanism on my F3P when I was reinstalling the front panel.

I was also unable to identify tiny spacers that fell out of the case when I opened it. The repair manual was silent on this.

If I'm unlucky, the new F3AF, which works except for the LCD, will be a total write-off after this procedure. And I don't think that anything in the electronics will come loose on its own at this point.

I think I'll end the project here and put the F3AF back in the closet

 

[Andreas Thaler]

Couldn't it be a faulty LCD after all, even if it's unlikely that two LCDs have the same fault?

I have a another LCD that is already removed, and I'll put it in for testing.

Then that's it

 

[Andreas Thaler]

Faulty LCD display: Identifying the area to be checked according to the repair manual

The troubleshooting section in the repair manual states that if the LCD display is faulty (which corresponds to the one in my F3AF), a specific checking land on the left front board should be checked. On its underside.

To get there, the front panel of the F3(AF) must be removed.

I look at the area on a practice F3 that has already been dismantled and is largely identical to the F3AF.

Checking Land #49 should be checked for separation at the solder joints to the next board part.

Loosen the two screws.

The circuit board can now be unfolded.

All circuit board parts of the F3 are connected to each other, so the circuit board is one piece.

Rotate the camera 180 degrees.

Here is the part of the board that needs to be checked (see the illustration in the repair manual above).

The two arrows point to the soldering of Checking Land #49. Once on the lower part of the board and once on the connected upper part.

I doubt that anything has changed on my F3AF by itself.

That's why I'm leaving it at this exploratory tour and won't open up and check my F3AF.

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Checking the LCD polarizer on the Nikon F3AF

@4season pointed out in this thread that the polarizer above the LCD could be faulty. This is a film polarization filter that is glued under the LCD viewing window on the housing.

About the technology:

What Is an LCD Polarizer?

Liquid-crystal displays (LCDs) consists of electronic display devices — TVs, computer monitors, smartphone screens, etc. — that feature liquid pixels. There are other display technologies on the market, but none are more popular than LCD. Research, in fact, shows that nearly 200 million LCD TVs...

nelson-miller.com

I would also like to check this on my F3AF.

To do this, I remove the polarization filter from my practice F3.

Above is the LCD housing with the viewing window on the left.

I cut out the polarizer.

When placed on the LCD window of my F3AF, the faulty display does not change even if the fiter is rotated.

I do not believe that the polarizer that is still installed is counteracting this and therefore rule out the possibility of a faulty polarization filter.


Conclusion

• The faulty LCD display in the Nikon F3AF could not be corrected by replacing the display twice or by adding a second polarization filter.
• A further check for an electronic fault would mean dismantling the F3AF, which I have ruled out in order not to expose the camera to any risk during subsequent assembly.
• Therefore, no solution, the camera is going back in the cupboard.

But so that the expedition is still of some use, I am now putting together a tutorial for replacing the LCD.

Tutorial Nikon F3(AF): Replacing the LCD

On the Nikon F3 and its versions, the LCD that is reflected in the viewfinder can fail partially or completely. Corrosion of the LCD connections could be a cause, or the LCD sandwich no longer seals tightly; black spots can also appear that make the digits unreadable. The only solution here is...

www.photrio.com

I had tried a third LCD, but it showed the same faulty display as the previous two. I therefore assume that there is a circuit fault and know that these three LCDs work.

At least that is good news for future replacement projects.


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