The R4 who lived

[Vito Meuli]

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Hello!

I just bought a cheap Leica R4 MOT Electronic, supposedly dead.

It's one from the first batch (SN 1535123), the more troublesome as I read around.

I intended to tinker with it a bit, and hopefully find the fault. I'm an absolute beginner as repairman, I know I'll probably only make it worse :-)

It's working properly on 1/100 (mechanical), whereas it seems to be dead otherwise: no battery check, no LED in the viewfinder, no electronic shutter. My first guess is something obvious is broken: some wire around the battery compartment maybe. A first inspection showed nothing interesting, except the wiring has colors different from what stated on the Minolta XD 7/11 Service manual. I simply opened the bottom cover and checked the little wires.

Then I tried attaching the Motor Winder and...hold and behold...it works!

When getting energy from the Motor Winder, the electronics works: the shutter fires, the LED light up.

So it's not really dead!

I don't know if it's metering properly or not, or if the shutter fires with proper timings. At least there's life, and hope.

Next time I'll dig a little deeper. Any advice?

Edited July 24, 2024 by Vito Meuli

[Vito Meuli]

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Simply register for free here – We are always happy to welcome new members!

[spydrxx]

Shoot a test roll. Seems like a nice catch.

[Eclectic Man]

You should be able to find someone with an electronics background to help you check the contacts and connections.  It could be something as simple as a single loose connection.  One thing to check is, does it rattle if you shake it gently?  If so then there may be a loose screw inside.

[R-ler]

LUF Germany.  Auslöser R4  17.02.2024. Read.

[Vito Meuli]

On 8/3/2024 at 4:04 PM, Eclectic Man said:

You should be able to find someone with an electronics background to help you check the contacts and connections.  It could be something as simple as a single loose connection.  One thing to check is, does it rattle if you shake it gently?  If so then there may be a loose screw inside.

Yes, what I need is some basic knowledge of the electric circuit.

Unfortunately the Minolta service manual is not enough, it doesn't describe the motor winder connections. My guess is there should be some switch to pick energy from the motor drive instead of internal batteries, when one motor is attached. Such switch is my first candidate culprit.

Otherwise some broken wire or solder.

Something loose inside is already known: I pressed the transparent round window of the battery check LED and it fall inside :-( So now there something loose, who knows if one or two.

Edited August 11, 2024 by Vito Meuli

[Vito Meuli]

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On 8/3/2024 at 6:52 PM, R-ler said:

LUF Germany.  Auslöser R4  17.02.2024. Read.

Thanks a lot!

Reading it in German is more difficult, but can be done. I'll report if it covers the same problem as mine.

[R-ler]

vor 1 Stunde schrieb Vito Meuli:

Thanks a lot!

Reading it in German is more difficult, but can be done. I'll report if it covers the same problem as mine.

Translate it by clicking right mouse button.  select language menu field !

[Jamison]

The problem with early R4's was some sort of condensation spoiling the electronics in the upper area around the pentaprism.  There was a product wide recall.  I remember that part of it well.  I was US Leica camera product manager, at the time.  US office may have more details on record.  You might want to mention that the repair was at no cost back in '82.  Hopefully, that helps.

Edited January 26 by Jamison

[Deeetona]

Happy to help with translations if needed.