Leica R3: Mission Aperture Priority

[Nimbus62]

oups.. I change the credentials. Now will be fine for everybody.

About your failure in automatic mode, check connectivity or Tr12 (pin 4 and 5 from top circuit) to the control board C2 and S4.
it is not used in manual mode.

I added the picture of the top ceramic board with wire connection to the Leica add-on (pot, switch, bottom cell)
For your information, the ceramic board is a Minolta XE board where they cut 3 connection (see red lines).

I am working on a Service manual for LEaica R3 but have no time at the moment. I am working on Minolta XM project.

Last point: to adjust the cell response, have to adjust first Cds Spot as describe for XE with R23=RL R22=RS then adjust CLC Cds cell. What is not clear is the way to adjust R21 (RP) at the moment do not change/adjust R21. The most important is
1) to use clean and lubricated pot for Rsv and Rav. I use "Deoxit Fade Lub" with cotton buds. Do not spay directly!!!
2) to adjust correctly the current generator R1 and R2.

 

[Nimbus62]

To yong to be able to send PM....
Here it is.

 

[Andreas Thaler]

oups.. I change the credentials. Now will be fine for everybody.

About your failure in automatic mode, check connectivity or Tr12 (pin 4 and 5 from top circuit) to the control board C2 and S4.
it is not used in manual mode.

I added the picture of the top ceramic board with wire connection to the Leica add-on (pot, switch, bottom cell)
For your information, the ceramic board is a Minolta XE board where they cut 3 connection (see red lines).

I am working on a Service manual for LEaica R3 but have no time at the moment. I am working on Minolta XM project.

Last point: to adjust the cell response, have to adjust first Cds Spot as describe for XE with R23=RL R22=RS then adjust CLC Cds cell. What is not clear is the way to adjust R21 (RP) at the moment do not change/adjust R21. The most important is
1) to use clean and lubricated pot for Rsv and Rav. I use "Deoxit Fade Lub" with cotton buds. Do not spay directly!!!
2) to adjust correctly the current generator R1 and R2.

Thank you!

I'm obviously speaking to an electronics engineer here, excellent!

 

[Andreas Thaler]

To yong to be able to send PM....
Here it is.

Thank you!

 

[TPrins]

Too bad i'm just reading this now. I was testing the looking at the caps and thought the ceramic capacitor looked rather bad (the brown 12v 50^3 one). When i turned it to auto, fired the shutter and short circuited the legs of this one it would fire immediately instead of taking a few sec. So i suspected it to be faulty. I just soldered it out and am looking online to replace it. Currently without it though, the manual times still are correct and the auto times are still taking a few sec. So nothing seemed to be changed, even after removing the cap.

 

[TPrins]

Thank you Nimbus! I'm trying to understand what to do. S7 could be the problem, so i need to check the voltage on pin 6 on IC1. IC1 is located under the film advance lever right? Which pin would be pin 6 in that case? And where would S7 be located?
I just removed the 12V ceramic brown capacitor, when i short circuited the legs of it, the shutter would fire instantly in Auto mode. So my guess was that it releases to slow. Now that i removed it everything stays the same. Manual speeds are okay, Auto mode takes very long. Very strange

 

[Nimbus62]

Hi, If manual spped are OK it is first important step: the electronic of managing the shutter is OK: IC1, C2, S3, S5, S7 M position are OK

To help you you can refere to Minolta XE service manual: everything outside Miror box is applicable. Considering Leica Miror box, switch functionality is the same, location are totally different.
The prisme, CDS cell and PCB A on top are the same.
comming back to your problem:

The point you have to verify: S7 but also the chain: S4, S'4

S7, it is located of PCB B S7 is located on top, near R10

I have to take a look to my documentation about S4 and S'4.....

 

[Nimbus62]

S'4 and S3 are on the contact holder set ( same as Minolta XE)
S4 is in the CLS shutter. In CLS documentation it is named "Trigger SW"
due to different miror box than XE, R3 SW5 is under the mirror box but seems to work correctly on you R3 (manual speed are OK)

Check that SW2 open correctly when you press the shutter button. (there is a second contact to open the meter circuit in spot mode) It is on the chassis of the body, directly activated by shutter button (same axle).

Check also the C1 cap under PCB-A. It is "flying connection under PCB_A and could be wrong.
You can check also Uev at C1 pin, something like
610mV for EV10 (1/30 f5.6) +18mv step per EV. take care to measure with High impedance multimeter.

 

[Nimbus62]

Here some documentation produced to locate switch on R3

 

[Nimbus62]

Another version based on Minolta XE documentation.
Sorry for the french....
SW5 Mirror box ( under mirror box,
CI-E is the small CI to support/connect Spot cell under the Mirror box.

 

[Andreas Thaler]

Another version based on Minolta XE documentation.
Sorry for the french....
SW5 Mirror box ( under mirror box,
CI-E is the small CI to support/connect Spot cell under the Mirror box.

Could you explain how the R3 calculates the shutter speed in automatic mode?

I assume that the times are stored as charges in the capacitors and controled via operational amplifiers, so it's an analog process?

 

[Nimbus62]

Yes it is analog calculation.

Shutter openning time is controled by C2 charge duration (associated with M5128K and the integrated two switching circuit to manage short exposure and long exposure).

In Manual electronic speed, C2 charge duration is controled trough Rt. Rt value is selected with the speed knobe.
C2 charge start when S4 is closed (synchronous with 1curtain start). The charg is negativ (start from +3V going to 0). At the beginning, Uc2 is 0V)
IC1 M5128 detect the C2 charg level comparing voltage at pin 10 and 8 with trigger level at pin 6.
When the charge voltage is crossing the trigger level pin 6, the First switching, delay and second switching circuit of IC1 M5128 control the magnet to releasethe second curtain.

In automatic, the condensator C2 will be charg with a current delivered by Tr12 (located in ICM5129K managing the cells and meter) associated with C1.
C1 condensator is charge with a voltage proportional to light measured by the cells.

I consider the cells bridge as one: Spot or Integral. The output is pin 2m (spot or integral selector).
The Cells bridge deliver a voltage Uev in direct relation to EV (take into account Light level, ASA, Aperture simulation). The voltage charg the capacitor C1.
Near 600mV for 1/30, 18mv per EV (+ for higher speed or minus for lower speed)
C1 is a memory capacitor (the big one, connected with 2 wire to PCB A (on top)).
It is used to memorize the light level when you take a picture: the miror will be up and no light on cells. The light is always memorized (on spot or Integral).

Now you take a picture, you look in viewfinder, the light is measured and bridge output 2m is connected to:
- Meter, via pin 6 of IC M5129K, output amplifier pin 11 go to meter via switch 4m/4a and S"2.
- C1 to charg capacitor.

When out press the release button (body ON, film advance completed)
1) This button open S2 the current light level Uev is memorized in C1
2) You continue to press, S3 is open, S5 is closed, Electronic control of the shutter is on, magnet is on (same step as in manual electronic speed)
3) You continue to press and the mirror start, when up, it start the shutter: first curtain start travel and at same time, S4 is closed (S'4 closed when armed).
Closing S4 start the charge of C2: C1 charge current is delivered by Tr12, Ic proportional to Ib produced by Uev voltage stored in C1 and applied at M5129K input pin 6.

When C2 charge is sufficient ( crossing trigger voltage of IC1 M5128K) it control the magnet through First switching, delay and second switching circuit of IC1 M5128.

Important:
To adjust the speed in Automatic mode : speeds must be accurate using Manual speed selection (adjusting R12 for high speed and R10 for long time exposure)
Then in automatique you have to adjust the step of 18mV per EV and Uev value for 1/30. High and low speed will be OK. If not have to check again everything.
Minolta XE Adjusment method is applicable taking care that Uev have to potentiometer:
alignment for spot measure: R25
alignment for Integral: R5 (this is XE)


Reminder:
To check speed:
1) check mecanical speed X, curtain speed in X and B mode (curtain will be lower due to age) -> Minolta XE documentation applicable
2) check Manual speed : they are electricaly controlled -> Minolta XE applicable
3) check Automatic mode:
a) Cell bridge current ( Minolta XE documentation applicable to adjust R1 an R2)
b) Bridge adustement Spot, R24, R23 and R22 (Specific to Leica but based on Minolta XE method; adjustment of R24 (Rp) is different)
c) Speed alignment Spot R25 (using Minolta XE method at 1/30)
d) Meter alignment for Spot (using Minolta XE method at 1/30)
b) Bridge adustement Integral R21, RL and RS (Specific to Leica but based on XE Minolta method; adjustment of Rp is different, calculation is the same)
c) Speed alignment Integral R5 (using Minolta XE method at 1/30)

That's all...

 

[Nimbus62]

About Cells bridge Leica use same electronic as Minolta (IC where designed for XM, X-1 and XK and XE) The implementation are very similar in XM series or XE.
In Leica R3, Leica added this Spot cell connected with wires to the PCB A (ceramic circuit on top of the penta prism) via a 4 switch PCB and a 5 potentiometer board.

There is no redesign of the electronics.
The spot bridge works in the same way Minolta designed it.
In Spot, spot cell is alone
In Integral, the signal of the two bridges are added, ratio defined with R27 and R26. We have the CLC of Minolta with little more sensitivity in the middle.

About PCB A in ceramic, it is the same as Minolta XE with 3 cuts (red line on the picture).... done for 55000 bodies....
Take care that ceramic PCB are more or less paired with Cds cells. Normally they are standard but Minolta adjusted the resistance lyed on ceramic for each body. Certainly the same for Leica.
You can replace PCB A with one from anothe body but take the Cells (and penta prism).

I am working on a method to dismantle the miror box without removing all wires.... Only minimum.... Not easy....

 

[Andreas Thaler]

THANK YOU!

 

[Nimbus62]

HI, In the R3 schema I use the same notation as Minolta XE for parts which are common. Then it is easy to read the Minolta service manual for XE looking at the part on the R3 schema.

 

[TPrins]

Nimbus, thank you soo much for these insane reactions. I feel like im talking to the designer of the camera itself. Sadly i feel like this problem is starting to go to deep for me. I've repaired quite a few SLR's and point and shoots, but i'm getting pretty stuck on this one. Electronics aren't my strong point, i'm a mechanical engineer . I believe that what i circled is S7 and check the wires of PCB1 pin 4&5. At some point i though, maybe there is just dirt somewhere, so i sprayed it with isopropyl alcohol a little and blew it dry. Then the auto mode fired fast, but B and X got stuck when fired. Now i'm back to square one. Firing at mechanical speed at all speeds... I'm getting a bit done with this one. When i got the camera, this was the same problem. Firing at 'x' at all speeds except 'B'. Then i managed to take the front partially off and clean the magnets with a toothpick with isopropyl, and the manual speeds worked since then. But now it's all mechanical again. To take the front off was already such a hassle and a miracle i managed to put it back together that i'm doubting if i want to try that again. I'm almost considering asking if i can send it to you in France
I've been studying everything you've send for hours, using chatGPT where i couldn't follow it. Again, thanks for sharing all your wisdom. merci beaucoup

 

[Nimbus62]

TPrins, sorry you do not success yet.
No problem to send it to me but at the moment very busy with my own project.

Just to be sure to well understood were you are.
Could you answer if the different point here under are OK:

Fist point The mechanical speed, to be sure to test them, remove the battery.
With no battery, opening the back of the body, using X mode you see light when shutter start OK or KO
other speed than X give 0s exposure - no light visible (second curtain and first one start at same time) OK or KO

With battery, you activate the electric control of second curtain. Test low speeds 1 2s and 4s are working OK or KO

In automatic mode, always low speed or high speed or no light (second curtain start immediately?

 

[TPrins]

TPrins, sorry you do not success yet.
No problem to send it to me but at the moment very busy with my own project.

Just to be sure to well understood were you are.
Could you answer if the different point here under are OK:

Fist point The mechanical speed, to be sure to test them, remove the battery.
With no battery, opening the back of the body, using X mode you see light when shutter start OK or KO
other speed than X give 0s exposure - no light visible (second curtain and first one start at same time) OK or KO

With battery, you activate the electric control of second curtain. Test low speeds 1 2s and 4s are working OK or KO

In automatic mode, always low speed or high speed or no light (second curtain start immediately?

Hey! sorry, late reply

- no battery, open back, X: i see light
- no battery, open back, other speeds: no light
- battery, manual speed 1s 2s 4s: mostly work, sometimes faster, sometimes no light
- battery, automatic: sometimes really long (+10 sec), sometimes no light

hope that helps. I can always send more info or a video

 

[Nimbus62]

Hi, no problem, we have time....

1) no battery, open back, X: i see light OK
2) no battery, open back, other speeds: no light OK normal.
3) battery, manual speed 1s 2s 4s: mostly work, sometimes faster, sometimes no light ---> here first problem to solv.
4) battery, automatic: sometimes really long (+10 sec), sometimes no light

Point 3 manual speed : must works perfectly before working on last point: Automatic

Manual electric speed, what to check:


fist: cleaning S'4 using deoxid. (remove the bottom plate, it is in visible in a small window in the middle. They are moved by a nylon lever from the mirror box)
Second cleaning of SW7 but (if not wrong, you did it).

To clean the switch contacts you must use Electronic contact cleaned "Deoxit or KF F2 or other similar product". but you cannot spay!!!
You have to put some liquid in a cup and then use a 0.6mm watchmaker screwdriver or "oil stick" to put one drop of deoxit fluid on the contact.

To clean the contact I select the B speed,
the first contact on top (normally closed): put one drop on the contact then trig the shutter many time.
for the second activate the shutter to close the contact, put one drop on the contact then trig the shutter many time.


normally must obtain stable long exposure 1sec for example.

If not the case, will need deeper investigation. Before going there, could you clean/deoxit the contact.

Best regards.

 

[TPrins]

Hi, no problem, we have time....

1) no battery, open back, X: i see light OK
2) no battery, open back, other speeds: no light OK normal.
3) battery, manual speed 1s 2s 4s: mostly work, sometimes faster, sometimes no light ---> here first problem to solv.
4) battery, automatic: sometimes really long (+10 sec), sometimes no light

Point 3 manual speed : must works perfectly before working on last point: Automatic

Manual electric speed, what to check:


fist: cleaning S'4 using deoxid. (remove the bottom plate, it is in visible in a small window in the middle. They are moved by a nylon lever from the mirror box)
Second cleaning of SW7 but (if not wrong, you did it).

To clean the switch contacts you must use Electronic contact cleaned "Deoxit or KF F2 or other similar product". but you cannot spay!!!
You have to put some liquid in a cup and then use a 0.6mm watchmaker screwdriver or "oil stick" to put one drop of deoxit fluid on the contact.

To clean the contact I select the B speed,
the first contact on top (normally closed): put one drop on the contact then trig the shutter many time.
for the second activate the shutter to close the contact, put one drop on the contact then trig the shutter many time.


normally must obtain stable long exposure 1sec for example.

If not the case, will need deeper investigation. Before going there, could you clean/deoxit the contact.

Best regards.

I took the bottom off and cleaned S'4 with some isopropyl, i don't have contact cleaner atm.
afterwards i fired the shutter a lot of times and the result is the same.
on '4s'
- fires instantly, no light through shutter
- fires but shorter than 4s. between 0.5s and 2s.
switches between these 2.

also cleaned what i believed to be S7 before.

 

[Nimbus62]

Do you clean Rt contact (speed selector brush)?

What could be checked is S5: control board power supply when activate shutter.
To check it:
- remove right cover (speed dial side), select B speed,
- remove battery, with a voltmeter ( basic one suffisent) measure the battery voltage, save it.
- insert battery,
- Activate the shutter and maintain it open
- Measure the voltage after S5 on the control board: track connecting pin 11 of IC1 (14 pin flat pack)

Must have same voltage or near (2,90V)

Do this test 4 time, If low or not stable it is a problem with S5.

Check trigger level pin 6 of IC1:
B speed, press shutter button and maintain shutter open
You must have something like 1.6V at pin 6

Check S3 open using B speed and shutter open, miror up -> S3 must be open; with ohm-meter check at C2 pins must be different from 0 Ohms (infinit or hight value)
Check S3 closed: shutter closed, miror down, ; with ohm-meter check at C2 pins must be 0 Ohms or some milli ohms.
If S3 not, check the cabling and if OK must open the body to adjust S3.

If all above OK, certainly a problem with S4 inside the CLS shutter, must open the body to remove miror box....
Not easy...

 

[Andreas Thaler]

If all above OK, certainly a problem with S4 inside the CLS shutter, must open the body to remove miror box....
Not easy...

Doable, see

Leica R3 ELECTRONIC: Stiff mirror mechanism repaired

The shortcut with Zippo, Nyoil, syringe and cannula worked on my Nikon F4, but not here. What I have seen is enough. It is not possible to control the placement of the oil this way. If you add Zippo, you have a diluted oil soup that spreads. Even small amounts are enough for that. The only...

www.photrio.com

The service manual for the Leica R3 MOT ELECTRONIC should also be usable for the Leica R3 ELECTRONIC, as the cameras are largely identical:

Leica R3 MOT Parts Diagrams

Factory parts diagrams

learncamerarepair.com

 

[Nimbus62]

Hi Andreas, about the mirror box, I agree, Doable but better to check everything before opening....
I do not like because have to unsolder some connection. If we can avoid it is better.

About the R3 MOT Electronic, I already have this documentation. I confirm: Electronic is exactly the same for shutter control and flash circuit. There is only additional circuits to control the winder.
R3Mot had some mecanical differences but minor changes.
I already build my documentation (In french) based on Minolta XE documentation

To debug the electronic, I use digital oscilloscope synchronized on flash trigger contact (if works..) It is easy to check the electronic and to see what appended before and after trigger: 3V power stability, Mg control, condensator charg/discharg.
Debugging possible with multimeter but not so direct.

 

[jajong]

Hi Andreas, about the mirror box, I agree, Doable but better to check everything before opening....
I do not like because have to unsolder some connection. If we can avoid it is better.

About the R3 MOT Electronic, I already have this documentation. I confirm: Electronic is exactly the same for shutter control and flash circuit. There is only additional circuits to control the winder.
R3Mot had some mecanical differences but minor changes.
I already build my documentation (In french) based on Minolta XE documentation

To debug the electronic, I use digital oscilloscope synchronized on flash trigger contact (if works..) It is easy to check the electronic and to see what appended before and after trigger: 3V power stability, Mg control, condensator charg/discharg.
Debugging possible with multimeter but not so direct.

Hi Nimbus, Andreas and Tprins,I have been following this thread with interest. My R3 was a mess when I got it. Manual 500 and 1000 were too fast: fiddling with R12 solved that. On automatic speeds were way too slow and getting slower after a few tries. So, on reading all the useful information I started cleaning pots and switches. That didn't help: manual speeds were okay, but automatic speeds too slow ( up to10s of seconds! ). I decided to replace capacitor C1 ( 2,2 uF 16 v ) and automatic times are now normal ( they need adjustment, but automatic behaviour is consistent.) . The original capacitor C1 (beige one under PCB-A ) was faulty.

Another thing I found out when working on this camera was that the spot/average switch can be pushed too far forward when the bodywork is off. The result is that the camera starts behaving: suddenly automatic speeds are too slow ( 10 or more seconds). So keep an eye on this switch when testing.

 

[Nimbus62]

Hi Jajong, many thank's for you kind advise about spot/average switch.

second point the way you proceed is correct: first test and adjust manual speed with the goal to obtain a stable shutter speed, then works on Automatic speed.

About Tprins problem could be a faulty C2 capacitor. But (from my experience), many time was a switch problem. It is the reason I prefere the approach a) to clean/deoxit switching; b) do an analyses with digital scope, measure speed, change C2 if needed, c) adjust the speeds low and high; d) debug/adjust Automatic.

About your Automatic alignment, you can do a partial speed alignment if interesting I will describe but you need: an IL9 source (I use my PC sceen displaying a grey zone adjusted with my Minolta Light cell at EV9) an IL14 source and 50mm f2 and shutter speed tester (working with the different light sources).