Canon T90: Surprise in the box

Andreas Thaler

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Some time ago I bought a Canon T90 on eBay, which the seller said is in excellent external condition but showes no signs of life.

I haven't unpacked and looked through the camera yet.

This will be an exciting project, because even if I manage to wake the T90 up again, will its shutter work?

HELP and EEE as error messages for a defective shutter are the still unsolved and common problem with the T90.

We will also start this project next week.
 

ic-racer

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Would it be a dissapointment if it were fully functional after cleaning the battery contacts?

The last camera I got was a free N55...turned out to be fully functional (it is the one on which I tested the shutter and meter and found them better than any of my older cameras.) Even if there is nothing to repair, at least I was able to get some use out of my shutter tester

 
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Andreas Thaler

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If the T90 has no other faults than dirty battery contacts, I will complain to the seller
 
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Andreas Thaler

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Tomorrow morning (CET) I'll be looking at the T90. Maybe it will all be easy, or maybe not.

You never know what will happen, that's what makes it all so exciting
 

forest bagger

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Hello Andreas!
Andreas Thaler said:
You never know what will happen, that's what makes it all so exciting
Click to expand...
Yesterday I received an old Nikon 135/2.8 AI for repair which had a stiff focusing only.
My efforts to remove the bayonet in order to clean and grease the focusing helicoids led to three totally damaged screws which held the bayonet so firmly to the tubus that I had to drill them out...
 
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Andreas Thaler

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I hope you have replacement screws?
 

forest bagger

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Andreas Thaler said:
Please describe exactly how you proceeded. Pictures would be nice.
Click to expand...
There is nothing to describe more precisely.
Screws made of titanium are so tough that it is hardly possible to drill the head off without slight damage to the bayonet made of brass.
And removing the blunt of the screws which are glued like hell in the base made of aluminium is almost impossible.
 
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Andreas Thaler

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Let's see what surprises this Canon T90 has in store for us



Since I suspect a problem with the power supply, I already have a battery holder and my multimeter ready.






A very nice T90 with nFD 35-105/3.5~4.5 (latest version with plastic housing) is on the table.

And indeed, the camera cannot be switched on, the LCD remains blank.








Cleaning the battery contacts is enough to bring the T90 back to life.

But the camera won't fire. The index arrow on the LCD flashes and there is a slight ticking sound when I hold down the shutter button.

All clear, the mirror magnet needs to be removed and cleaned.




The contacts on the adjustment wheel are oxidized, and the LCD display only changes sporadically when you turn it.

By moving the wheel back and forth intensively, I can clean the contacts and the locking positions almost completely work again.

This saves having to remove the shutter release unit with the adjustment wheel for cleaning:

Canon T90: Fixing dropouts on the control wheel

A more annoying than serious problem with the Canon T90 is the control wheel on the handle, which turns in notches that sometimes no longer make contact. You then have to turn the wheel one or two positions further in order to be able to set a shutter speed or an aperture value, for example. I...
www.photrio.com




All ready to remove the battery compartment and front cover to get to the mirror magnet.














 
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Andreas Thaler

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The battery compartment is removed …








… and also the front cover.






I remove the mirror magnet and clean its three contact surfaces with electronic cleaner.

I have described the details of this process here:

Canon T90: Cleaning the mirror magnet

I have a T90 here whose mirror magnet no longer works. The usual symptom of a quiet clicking sound and a flashing arrow in the display occurs. The recommended cure of removing the front cover and activating the - easily accessible - magnet with a magnetized screwdriver tip works with patience...
www.photrio.com




After I reinstalled the mirror magnet, the camera fires. But then the display on the LCD goes out.

I measure the battery voltage on the battery compartment and on the circuit board, but can't find anything wrong. Except that the battery voltage on the circuit board is slightly reduced.

So I unsolder the battery compartment and connect the T90 to my 6 volt laboratory power supply.

Now the camera also releases in series in HIGH transport mode, but the motor runs slower than usual. The first time the shutter is cocked, it is done in slow motion and the motor makes a strange noise.




I solder the battery compartment back on and clean its contacts again.

In addition to the positive and negative connections, there is a third (yellow) cable from the battery compartment to the circuit board in the camera. Maybe this is needed to ensure that the motor runs smoothly?




Now everything works.

I don't know what the fault was.






The damper under the two shutter curtains is rotten and falling apart. This is typical for most T90s today.

I use a probe to remove the sticky remains of the damper from the bottom of the shutter and clean the area and the shutter curtains with Zippo lighter fluid.

You can read more about this here:

Canon T90: Advanced cleaning of stuck shutter blades

Sticky shutter at EOS Nano Burger gives in „Manage Your EOS Camera’s Sticky Shutter“ https://www.instructables.com/Manage-Your-EOS-Cameras-Sticky-Shutter/ a guide on how to clean stuck shutter blades in a Canon EOS. The reason for the sticking is a small damper under the vertically running...
www.photrio.com






Everything clean now.




All functions, as far as can be seen, are ok.

Another T90, almost mint, joins my T90 family


+++

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

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Great job on a wonderful camera. I have followed similar instructions to yours for shutter cleaning and it really works. Sometimes it is all that a 30 year old camera needs to keep going.
 
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Andreas Thaler

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loccdor said:
Great job on a wonderful camera. I have followed similar instructions to yours for shutter cleaning and it really works. Sometimes it is all that a 30 year old camera needs to keep going.
Click to expand...

Thanks!

So far, with two exceptions, I've been having the same problems with the T90.

Except for HELP/EEE (shutter malfunction), they're all pretty easy to fix.
 
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Andreas Thaler

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I had activated the current limit on my lab power supply. This could have caused too little current to flow into the motor(s) for the shutter, mirror and film transport.

Anyway, it works now.
 
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