T90 problem - help needed

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I have a 8/10 year old T90 that has the following problem:

After loading film everything is fine, the LCD display and all functions are OK, frame counter reads 1 etc. Once I press the shutter button to take a shot the following happens: The shutter opens/closes as normal and the film advances, at the same time I get a help warning in the viewfinder and an EEE on the LCD display. This stays like this when the camera is on and even when I switch from A to L the EEE warning stays on the LCD. The only thing I can to to get back to the normal state is to open the battery compartment, powering down the camera and then reinserting the battery pack at which time the camera starts as normal and I can take a shot before the system goes belly up again, and I restart by removing the batteries.

Any thoughts out there....the camera is 10 years old (I think...it was bought second hand in the US) and has has ~200 films passed through it, but it has spent a lot of time in salt water environments in the tropics, but there is no sign of corrosion. The only other problem with the camer is that the lens mounting ring is a little loose.

I'd really appreciate any help since I love this camera....it's far more comfortable than an EOS-1 even.

PS....is ther anybody in Ireland who can service a T90.

-- Alan Ryder (science1967@yahoo.co.uk), February 19, 2002



Your T90 has probably a dirty magnet in the mirror box. This is the most common problem with T90's. It's an easy fix, but it requres removing the mirror box. A good CLA would fix it. I have no idea where though.

The lens mount is also easy to fix. You can find the service manual at http://www.canonfd.com if you'll do it yourselves.


-- Ketil (ketiljo@stud.ntnu.no), February 19, 2002.

I have a simular problem with one of my T-90s. It seems that its an on going problem with this one body. The other body that I have has had no problem since I purchased the cameras the first year of production.

The one body that gives the problem you mentioned has done it twice in its history. The Canon Technician told me it was a shutter problem but I didn't ask for specifics. The first time it was repaired and the camera worked for a 1 1/2 years. It now sits gathering dust because Canon can not guarantee that the problem will not happen again.

-- Terrance Blomgren (eqp@telusplanet.net), February 19, 2002.

Yeah...I think that it is the shutter magnet...I opened the T90 up and checked everything else (tightened lens mount). Unfortunately one of the screws holding on the topcover has become corroded and I have not been able to remove the topcover to clean the magnets.

-- Alan (science1967@yahoo.co.uk), February 20, 2002.

In addition to the copy of that third-party T90 repair manual Ketil mentioned at

http://www.canonfd.com/t90serv/index.htm ,

there is also a good exploded diagramme at

http://groups.yahoo.com/group/CanonFD/files/%20Manuals/t90repair.htm .

The latter is a .TIF file packaged as T90PARTS.ZIP. It contains 45 pages in one .TIF document. You'll need a viewer capable of paging through the document. If you don't have Kodak's "Imaging for Windows" (included by Microsoft with several of their Windows OSs), "Polyview" from polybytes.com works well.

Your camera is going into "error detection mode" (no operation, EEE on LCD). Error detection mode can only be reset by SW-3 (the reset switch) which is activated by removing the battery pack. By design, the A-L (advance/lock) switch does not clear the error mode, so don't fret about that.

First check that you have fresh batteries.

The camera can enter EEE mode because of either a problem in the camera OR the lens. Try operating the camera with the lens removed. If everything's okay, the problem is with the lens. Lens problems are usually due to excessive drag in the lens' diaphragm. This is most often the case with 3rd party (non-Canon) lenses of longer focal lengths.

If the problem is not in the lens, the most common cause within the camera is the shutter, although other causes are also known.

If I may presume to append a couple things Ketil said: 1) Although it's fairly common for mirror release magnet MG2 to gunk up and stick, that problem will NOT cause the camera to enter "error detection mode." Both of my manuals and some experience confirm this.

2) Mirror release magnet MG2 can be cleaned WITHOUT full removal of the mirror box (although the four screws holding the box must be removed and the mirror box partially tipped out. This is easy. MG2 is on the bottom, film-spool-side of the mirror box. The electromagnet is the connected to two wires: one black, one orange. The solvent of choice for de-gunking parts is Ronsonol lighter fluid. But let me repeat, this is not your problem, Alan.

Does the shutter release and do the curtains open? (Test on "Bulb.") If they don't, you're facing several possible shutter faults.

Just to give you an idea, the manual will tell you to check the following:

- cracked solder joints to the shutter's flexible printed circuit board (FPC or "flex") connector

- insufficient shutter curtain overtravel, preventing re-latching

- damaged shutter curtains

- defective DC/DC converter

- cracked orange wire solder VPP to DC/DC converter (if shutter releases BUT curtains don't open)

- (if shutter doesn't open) 1st curtain magnet, transisitor TR1, or no release signal received

(There are more! For these last, and for the other tests in the manual, you'll need a logic probe.)

My other manual takes a wholesale re-soldering tour to address possible wiring problems:

SW14, SW15, D10, D11, D12, D13, IC3 pins 20 & 21, shutter FPC, Main FPC solder points on right-side of prism, SW13, SW18, SW19.

It also lists numerous other checkpoint that are beyond the scope of this e-mail.

Best of luck.

-- Robert Segal (robertsegal@juno.com), February 20, 2002.

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