Nikon F4: Replacement of the smaller LCD, guide rails for the DP-20 viewfinder lubricated, aperture control function assessed

[Andreas Thaler]

I considered the best approach for turning two defective Nikon F4 into one working camera.

The decision depended on the condition of both SLRs and is based on a check.

The shutter of F4 #1 did not work properly. The shortest exposure time of 1/8000 second could not be measured on the camera tester.

But the shutter of F4 #2, which was intended as a replacement, also turned out to be defective.

I therefore decided to replace the smaller display on F4 #1 (donor: F4 #2) which had leaked and was no longer readable. This F4 can also be used for my photography work without 1/8000 second.

I also noticed that the DP-20 viewfinder could only be pushed onto the camera with resistance.

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LCD



I replaced the smaller LCD screen in the F4. The pictures show the process in chronological order.

The replacement LCD is fault-free and displays all digits.



For comparison, you can also see the replaced LCD, which shows the typical discoloration. Nothing can be repaired here.

Note:

• There are no complications, you just have to be careful not to damage the flexible circuit board on which the LCD sits in a housing when pulling it out a little to work on it.
• On the LCD, which is made of glass, there are two conductive rubber strips that provide the electrical connection to the contacts in the housing. Be careful when removing the LCD that these strips do not come off.
• I used an angled pointed probe to carefully lift the LCD on one side.
• The indentations in the conductive rubber strips from the pressure of the contacts show how it must be inserted.
• All parts fit together seamlessly; if something does not work, check that everything is in position.
• I strongly recommend always working in accordance with ESD (Electrostatic discharges) standards when opening electromechanical SLRs, i.e., preventing electrostatic discharges that can damage ICs. See also ESD safe working on electronically controlled cameras.

 

[Andreas Thaler]

See also

Nikon F4: Upper LCD replaced

Today I opened some packages of cameras that I received last year. There was also a Nikon F4S that I hadn't even thought about. Clearly used extensively, signs of use, but with a flawless viewfinder LCD at the top and a LCD at the bottom with only a small dark spot. Unfortunately, the fact...

www.photrio.com

Note:



Please ignore there the first image.

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Guide rails for the DP-20 viewfinder

I couldn't adjust the guide rails for the viewfinder, which can only be pushed on with resistance, any better using the four mounting screws.

Since another DP-20 viewfinder can be attached without any problems, the problem lies with the viewfinder.



Cleaning with isopropyl alcohol and a wafer-thin film of grease on the guide rails solved the problem.



Aperture control

• The smallest aperture closes completely, albeit with a slight delay.
• When the shutter is released, it can also be seen that the aperture lever in the mirror box does not fold down completely.
• There is also the typical screeching noise when the depth-of-field preview button is pressed.

All of this indicates that the aperture control needs servicing.

However, I assume that it is still possible to take photos with the F4 without any problems, as the delay of the smallest aperture is barely noticeable.

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Conclusion

A mint Nikon F4 with MB-20 battery grip is ready for action again.

We don't care that the 1/8000 second shutter speed doesn't work. But keep it in mind if necessary.

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A word of caution

Please keep in mind that you’ll be using highly flammable solvents for service work, and their fumes are harmful to your health. Soldering also produces fumes that should not be inhaled. Dangerous high voltages can be present when handling electronics, especially in conjunction with electronic flash units and mains. Therefore, familiarize yourself with the safety regulations beforehand and ensure your safety. Depending on the activity, protective gear may be advisable.

All information provided without guarantee and use at your own risk.

Acknowledgments

Without the work of Master Larry Lyells, in particular, we wouldn’t have the detailed technical information we need today for service/repair of SLRs.

The SPT Journal and The Camera Craftsman, which he helped shape significantly as an author, and which contain all the necessary information and instructions are available for a fee through Learn Camera Repair.

We owe our access to them to Eugene Pate, the founder of Learn Camera Repair.