Canon T90: recommendations and notes

Andreas Thaler · Apr 27, 2025

Canon T90: The infamous HELP/EEE error fixed through guided and systematic troubleshooting

We've discussed the Canon T90, arguably the most complex 35mm camera with MF, several times here. It's encouraging that most of the common problems can be solved DIY, see: https://www.photrio.com/forum/threads/canon-t90-recommendations-and-notes.202884/ However, one problem that means the...

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moggi1964 · Apr 28, 2025

Andreas Thaler said:
Repair shops shy away from the T90, at least that's been my experience.

Unjustifiably so, because it's designed for easy service. For example, you can access the shutter's electronic controls for tests without much disassembly, and you can also adjust both curtains with minimal effort without having to remove the shutter.

Instructions for service work are available, and the Canon Repair Manual also provides helpful tips.

Perhaps you can find someone willing to do the work?

Thanks Andreas. I'll take a look and see what I can find.

Andreas Thaler · Apr 29, 2025

moggi1964 said:
Thanks Andreas. I'll take a look and see what I can find.

Maybe you'd like to try a repair yourself? Instructions are available, so you don't need a magic wand

moggi1964 · Apr 29, 2025

Andreas Thaler said:
Maybe you'd like to try a repair yourself? Instructions are available, so you don't need a magic wand

I mean, what's the worst that could go wrong, eh!!!!!

Andreas Thaler · Apr 29, 2025

moggi1964 said:
Thanks Andreas. I'll take a look and see what I can find.

moggi1964 said:
I mean, what's the worst that could go wrong, eh!!!!!

The worst that can happen is that nothing happens

Andreas Thaler · May 6, 2025

Canon T90: systematic troubleshooting, DC/DC converter replaced, one LED digit missing, sticky shutter, EEE again, summary

Checking a Canon T90 according to the troubleshooting instructions by Larry Lyells in the SPT Journal. https://learncamerarepair.com/product.php?product=1778 No sign of life. Battery compartment removed, measuring the input voltage on the DC/DC converter. Front and top cover...

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Canon T90: Address unresolved problems; broken plastic parts in Copal S shutter, epoxy, EEE/HELP/bc errors, troubleshooting partially successful

The Canon T90 is particularly fascinating because back in 1986, every available technology was used to create the most complex 35mm SLR without autofocus. Electronically and mechanically, packaged in a stylish and robust housing. Even today, the T90 is satisfactory, but knowing and mastering...

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Andreas Thaler · May 8, 2025

Canon T90: EEE error resolved - hint for disassembling/assembling; sticky second shutter curtain; setting the 1/4000 second

In my last two T90 projects, the EEE error appeared after disassembling/assembling the camera. I was now able to determine the cause and fix it. I found the solution, once again, in Larry Lyells' SPT Journal on the Canon T90 🙂 The arrow points to the pressure plate of the front connector...

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Andreas Thaler · May 19, 2025

Canon T90: Tutorial for DIY service and repair

I have gained enough experience in my recent projects to be able to offer a tutorial on standard service for the Canon T90 here on PHOTRIO. The work I recommend for every T90 (depending on the available equipment) is: cleaning the exterior, cleaning the contacts of the command wheel, cleaning...

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Andreas Thaler · Jun 1, 2025

Canon T90: release magnet, EEE/HELP/bc, C & C as saviors, mirror shock absorbers and cover, front flex connector acting crazy/alternative?, victory

Having suffered setbacks with my recent T90 projects, my pride was bruised 🤨 So I made another attempt and pulled the next T90 out of the repair box. Today I had to succeed! ⚔️ Both mirror shock absorbers are missing along with their mountings, the cover is no longer where it should be...

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Andreas Thaler · Jun 7, 2025

Canon T90: Solution found for the stubborn front flex connector, service and repairs on the T90 are no longer a gamble

It's happened to me several times now that I've serviced a T90, only to find the work was in vain because of unsolvable contact problems in the front flex connector. The front flex connector is located on the front release side, where the red self-timer LED is located. Three flexible circuit...

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Andreas Thaler · Jun 12, 2025

Canon T90: Final summary on DIY service and repair

I've spent several weeks working intensively on the Canon T90 and have written a few articles here. Sufficient to summarize what I have learned so far. Findings, observations, insights The main cause of the common problems are dirty magnets and contacts. Cleaning fixes this. The EEE/HELP...

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Andreas Thaler · Jul 17, 2025

Canon T90: Aperture issue resolved, shutter disassembled and cleaned, alternative method of removing the mirror box has proven itself again

One of the T90s I recently had on my desk, see https://www.photrio.com/forum/threads/canon-t90-the-infamous-help-eee-error-fixed-through-guided-and-systematic-troubleshooting.213274/ is exhibiting a problem with the aperture. Under the same lighting, the aperture opens wider at one point...

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Andreas Thaler · Jul 18, 2025

I think I'm done with the T90 now. All the usual problems have been discussed, and there should be solutions for all of them.

It may seem complicated, but the T90 is quite easy to service.

It's a fascinating camera, and it's worth keeping it in good condition. But you should get to the root of the problems and not rely on the usual fixes like banging it on a table, "re-magnetizing" something, or releasing the shutter 100 times a day. The latter can even be damaging, as the example of the bent shutter blade, which was probably caused by the gluing, shows (see link above).

It doesn't require any special tools; soldering isn't rocket science. And if you don't take action yourself, no one will, or only for a lot of money

Andreas Thaler · Jul 18, 2025

Here comments someone who no longer has to prove his competence in repairing.

Gus Lazzari on the T90 and its problems:

https://www.photo.net/forums/topic/533648-canon-t-90s/#findComment-6015678

With this I‘d like to close the topic

Andreas Thaler · Jul 18, 2025

Replacing the sticky damper in the shutter?

No part in a camera is without a function and that also applies to the damper in the shutter of the T90, which relieves the strain on the two curtains when they contract.

It is a soft plastic unit that is inserted between the shutter frames and becomes sticky over decades. The shutter then becomes unreliable, stops working or, in the worst case, can be damaged if the slats of the curtains stick and the tension springs work against them when released.

A replacement could be made from silicone, for example.

I do not have a replacement for my work T90, but I trust that the curtains can withstand the strain given my use, which only amounts to a few films a month.

At the same time, I am monitoring developments so that I can make provisions for my other T90s if necessary.

I would advise every T90 user to keep an eye on this topic.

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Canon T90: recommendations and notes

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