canon 400mm 5.6 contact replacement

Hi All,

I bought a broken canon 400 5.6 off of Ebay recently. It looks like it was being used by a company to be controlled off the camera body. The contacts were snipped out. I found the parts manual and was able to get the part/two microscrews. I figured this would be a good forum to ask people for any advice on on fixing.
I have read the information I could find about where to connect the seven wires (ef pinout). Unfortunately, i could not find any videos or pictures for this particular contact/wire combination. Most of the forums online show newer versions with flex cables.
I know two wires are supposed to connect to the large ground and the last three are extra for a teleconverter. Any tips on the correct procedure or if someone has had experience with similar repairs I would appreciate.
some help. Thank you.
I have attached a picture of the lens with 7 wires, and a view of the contacts.

I don't see a 'large ground' in your picture. If you have a pin out it should account for all seven connections. You only mention five. I would be very surprised if two wires are tied together as you mention. In most cases, in this type of application, each wire is connected to one terminal. If two wires are common that is usually done internally within the strip. A big question here would be how are your soldering skills? This will take quite a touch, you better be good or know someone that is. Plus, this will require some fairly specialized tools. Ideally, a soldering iron with a variable temperature.

You'll need to strip the insulation from what is sticking out, which will be difficult. You don't want to remove very much as when you press the terminal strip into place the wires don't shift and contact each other.

Are you experienced with component level PCB repair?

I don't own a 400mm, or else I'd open it up and show you how it comes together. Anyone?

Thanks for the replies. I was unclear with my description. I meant there are 3 contacts out of the ten that are used by teleconverters that i don't need to worry about leaving the seven for my wires. I guess I am thrown off by this page showing "P GND" with two wires.

http://www.kimarco.nl …orner/eos_exten​der-uk.htm

http://static.photo.ne​t …d/00C/00CoOh-24559084.jpg

Maybe that has something to do with the diagram talking about a teleconverter?

I might be overcomplicating things and my seven wires connect to the seven contacts and i leave the last 3 for the teleconverter alone.

I probably am in over my head on this one as I dont have any soldering skills yet and just planned on practicing before trying on the lens.
Would I be better off going to a camera repair shop or electronics repair shop if I was going to go that route of having someone else put the part on? I would just prefer to give it a shot. I am using the lens manually with a wide open aperture so I figure at worst if I cant fix it it I am in the same position I am now.

Thanks.

I think you are going to need a service manual or else someone willing to open up their 100-400mm to have a look for you.

This photo of an EF 300mm circuit board has colors that seem to match yours but there are 9 wires not 7.

http://www.dhcameras.c​om …cu-board-repair-part-new/

Frederiksted wrote in post #17896980
Thanks for the replies. I was unclear with my description. I meant there are 3 contacts out of the ten that are used by teleconverters that i don't need to worry about leaving the seven for my wires. I guess I am thrown off by this page showing "P GND" with two wires.

http://www.kimarco.nl …orner/eos_exten​der-uk.htm

http://static.photo.ne​t …d/00C/00CoOh-24559084.jpg

Maybe that has something to do with the diagram talking about a teleconverter?

I might be overcomplicating things and my seven wires connect to the seven contacts and i leave the last 3 for the teleconverter alone.

I probably am in over my head on this one as I dont have any soldering skills yet and just planned on practicing before trying on the lens.
Would I be better off going to a camera repair shop or electronics repair shop if I was going to go that route of having someone else put the part on? I would just prefer to give it a shot. I am using the lens manually with a wide open aperture so I figure at worst if I cant fix it it I am in the same position I am now.

Thanks.

Maybe I'm missing it but I don't see any wire colors on theses pin outs. How do you know what wires go to what pins? With regard to the PGND being tied together, it appears there are two separate wires that attach to those two pins that are not tied together. You have seven wires and seven contacts.

The part that scares me the most is that you say you have no soldering skills. To do this kind of work isn't a matter of practicing for a few minutes and then have at it. When you solder anything the idea is to heat both pieces of work to the point where the solder is melted by the work and not by the soldering iron. This allows a good solder flow and a good joint electrically. Your contact strip has tinned copper contacts set in plastic. When you apply heat to the contact strip there is a very fine line when the contact heats to the point of being hot enough to melt the solder and being too hot that it begins to melt the plastic that it is set in. If that happens then the contact can and will shift it's position which can be a problem.

From your description it sounds to me that are indeed very much over your head on this.

Consider an overhaul...http://www.unitedcamer​a.com …6l-is-usm/#ShowSelections

Thank you. I reached out to them to see what the estimate would be.

I can vouch for United Camera. They do great work.

Frederiksted wrote in post #17898536
Thank you. I reached out to them to see what the estimate would be.

This EF 70-200mm F/2.8L IS USM II circuit board has 10 wires but it shows quite plainly where each colored wire is attached...