There are several common problems that the Nikon D70 can have. Seeing how the camera is over 15 years old, problems should be expected.
Sticky Rubber Grip
A common problem with older Nikon cameras is that the rubber coating on the grip and backs of cameras begins to break down. When the rubber breaks down, it becomes sticky.
I have written a guide on how to fix a Nikon D70 sticky rubber grip. Fixing the problem is not difficult or expensive, but it does take time.
You're going to have to slowly remove the sticky layer of rubber with rubbing alcohol (isopropyl alcohol). None of the other half dozen chemicals I tested had any effect.
Past a certain point of breaking down, all of the rubber will have to be removed. This is a common problem with some of Nikon's 35mm SLRs.
CHA Error / CHR Error
The CHA error can be mistaken for CHR as the LCD makes it hard to differentiate between an A and R.
This error message occurs when there is a problem reading a compact flash card. The most common reason for this is a bent pin in the card slot.
If you are getting the CHA error, take a look down into the card slot for a bent pin.
It is not going to be worth paying someone for the repair. You might not be able to find someone capable or willing to do it.
Compact Flash Card Reader Pin Repair
If you're up for a bit of DIY repair, the repair process isn't that difficult.
Removing screws on the body of the camera will allow you to remove the bottom and back panel of the camera. That will give you better access to the pins.
With access to the pins, you can try to bent the damaged pin back into place.
If that doesn't work, you might be able to find a replacement D70 compact flash card reader for sale on eBay.
FOR error - CF ribbon cable
The FOR error is another memory card related problem. However, this is a bit more difficult to deal with because it is a problem with a flexible ribbon cable.
The problem is caused by how the camera was designed. The ribbon cable that connects the CF card reader to the main board of the camera, makes a 90-degree turn.
Stress on the ribbon cable can cause the connection to fail. When that happens, the FOR error will appear.
Replacing the Ribbon Cable
Just like with the CHA error, it isn't going to be cost-effective to pay someone to perform the repair. You'd be better off by selling the camera as parts and buying a working replacement unless you're willing to repair the camera yourself.
The problem with this repair is finding a replacement ribbon cable. Your best bet is to look on eBay for a Nikon D70 replacement ribbon cable.
Unlike the card reader, there is not a specific name for the ribbon cable you need. You'll have to open the camera up and visually match the cable in your camera to what's on eBay.
Blinking Green Light of Death (BGLOD)
Poor quality electronics in the first 6 months of D70 production caused the blinking green light of death.
What happens is after taking a picture, a green LED flashes, indicating the memory card is being written to. The flashing never stops and the camera is unusable.
If you experience this problem, you can try to manually reset the D70 by pressing the small button on the bottom of the camera.
A service notice and recall was issued by Nikon. Unfortunately, enough time has passed to where Nikon is no longer doing the repair.
Nikon never released information about the affected serial numbers. This makes it hard to tell if a camera will potentially end up with the problem.
To see if the repair was done, you can look at the bottom of the tripod socket. If there is a black dot, the camera has been in for a recall repair.
Autofocus Not Working
There are several settings that can cause the autofocus on the Nikon D70 to appear to not be working.
Check AF/M Switches
There is a switch on the camera body and lenses that allow you to switch between autofocus and manual. Make sure both switches are set to AF or AF/M.
If either switch is set to M, the lens will need to be manually focused.
Is the Lens Compatible?
Are you using a lens that can use autofocus on the D70? Newer Nikon lenses may not work with the camera.
If you are sure the lens is correct, you can try to clean the CPU contacts on the lens and camera. To clean the contacts, use a small amount of rubbing alcohol on a cotton swab.
Check this out for more information on Nikon F-mount lens and camera compatibility.
Is Back Button Autofocus Enabled?
Back button autofocus is a popular feature to use. The feature disables the half-press autofocus on the shutter button.
Instead, the AE-L/AF-L button is used to turn the AF on. Press the button and see if it causes the camera to autofocus.
You can access this setting by turning on the detailed CSM menu you. That option is located under the settings menu with a yellow wrench.
With the detailed menu on, go to the pink pencil. The AE-L/AF-L option is number 15 on the menu. The AF AF-ON option will enable back-button AF. AE/AF Lock will disable back-button autofocus and reenable the shutter button half-press for AF.
The R07 Error message is not an error at all. It shows how many shots are remaining in the camera's buffer.
You will see the message show up when the shutter button is depressed halfway down.
If you change the image file format from JPEGs to RAW, R04 will show instead. That's' because RAW files are larger and use more memory in the camera's buffer.