The short version:
Nikon D70 CHA errors may be repairable by disconnecting and reconnecting both ends of the ribbon cable that connects the CF slot to the main board. See this excellent Nikon D70 iFixit guide for details about how to take apart and reassemble your camera.
The longer version:
Before we start, I should stop to say that this is a record of my experience, and I can’t guarantee that it will work for you. In other words, please use common sense… if you’re not comfortable handling a small screwdriver to remove parts of your camera, then it’s best to have your camera repaired professionally. Now, on to my little story…
I have a Nikon D70, which has been a good camera for many years. Over the last 2 years or so it has started to exhibit the dreaded “CHA” error, meaning that it doesn’t recognize the CompactFlash card in the memory card slot. Google tells me that other D70 owners have been able to fix this issue by replacing the CF slot, but I couldn’t find any replacement parts anywhere online. So, I decided to try to repair the existing one.
The Nikon D70 iFixit guides are great, and with a little patience I was able to remove the memory card slot assembly. I found that one pin was pushed all the way back into the plastic holder. At this point, I tried to push the pin back into it’s normal position. This was not really a good idea, as it snapped completely off the circuit board with the slightest pressure.
In my case, pin 50 was the pushed back and now broken off pin. (At least I think so… it’s the best I can figure based on the diagram at the bottom of this page: http://docs.oracle.com/cd/E19858-01/821-0078-10/z40000901448028.html) After consulting wikibooks.org, I found that pin 50 is one of several ground pins, so one of them missing shouldn’t affect the memory card’s operation.
So I decided to reassemble the camera and see what happens. (Nothing to lose at this point, right?) In order to get the CF slot assembly back into the camera, I had to remove the ribbon cable and connect it from the other side. It didn’t fit back through the way it came out. Although it was an accident, I’m pretty sure reconnecting this cable was the key to fixing the problem.
After finishing the reassembly, I turned the power switch on, and… it worked! It found the CF card on the first try. This in itself was an improvement over the previous state of affairs. It’s been about 2 weeks since the repair, and so far it hasn’t shown any more CHA errors.
I did the same repair on my dad’s D70, and his seems to be working again as well.
Hopefully this post can help others trying to figure out how to fix CHA errors on their Nikon D70. If you found this helpful, drop me a line on the contact page and say “hi”!