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John Neal
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, February 10, 2005 - 03:25 am: | 
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Hi, I have a nice GSN that takes good pictures, both meter lights work, but not at the same depression of the shutter button. I thought this may mean that the pad needs to be replaced, so have had look inside. The pad is an orange-brown rubber and in very good condition, but seems to be slightly thicker than the 2mm suggested elsewhere in the forum. I get a good clunk when winding on and all the mechanicals sequence correctly. The camera does not look to have been dissassembled in the recent past.
I know that the sliding contacts were a little dirty, but these have been cleaned with a contact specific spray cleaner. This has improved the permanance of the lights (ie they don't flicker as much now), but how do I get the lights to operate at the same depression of the shutter button?
I read somewhere that the two screws on the bottom of the primary & secondary shutter spindles can be adjusted to achieve this, but I do not know how, can anyone help?
Or is this the holy grail and I have to accept that they never will? |
Winfried
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, February 10, 2005 - 04:34 am: |
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Nothing is wrong with your camera. It is absolutely normal that the red light comes on on slight depression of the shutter button (if necessary) and the yellow light will go on (if demanded by lighting situations) on further depression of the button.
In any case, the yellow light should go off BEFORE the shutter clicks, and long time automatic exposures should not stop (i.e. the shutter should not close) when the shutter button is released. If any of the above is not the case probably the pad is to blame. |
John Neal
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, February 14, 2005 - 04:32 am: |
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Many thanks, Winfried, in most other cameras it is usual that the lights function at the same depression and I expected that this would be the case here too.
My yellow light does go out before the shutter fires but the long exposures seem to be a bit variable - at low ISO film speeds (25 or so), the shutter stays open for up to 2 minutes, but at higher speeds (400), the shutter sometimes stays open and sometimes closes as soon as the button is released - under the same light conditions.
Does this indicate a pad problem, or is it the metering circuit? |
Winfried
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, February 14, 2005 - 04:38 am: |
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I rather think it's a problem with dirty slide contacts. Open the camera bottom and check where the shutter shaft goes with a small flashlight, you might even be able to locate the slide contacts. Spray a bit of electronic contact cleaner in that area and press the shutter button several times. Helped on several Electros of different models. |
John Neal
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, February 14, 2005 - 07:35 am: |
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Winfried, thanks for that, but I have already done that a couple of times - it did make the lights more steady. Since my last message I have been testing the long exposures and the more I test it, the more erratic it becomes.
Now, sometimes the lens does not even fire, it just clicks without moving the diaphragm. Also, when it does open, it almost always closes as soon as I release the button.
Any other ideas? |
Winfried
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, February 14, 2005 - 07:43 am: |
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When the blades don't open at all maybe the shutter leafs are gummed up. This might also lead to your second problem: if the blades do not open completely the opening mechanism will not be latched by the shutter solenoid, and thus the shutter will close again as you release the button. I would recommend cleaning the shutter blades.
Another thing to check might be the electrolytic capacitor in the meter circuity. It usually is a tube shaped component (approx. 5mm / 1/4 inch long) with a figure like 2.2uF or 3.3uF printed on it. When replacing it you have to select the same value. Sometimes odd values are used which are not easily available - the meter circuit actually is adjusted by the value of this capacitor. However, for a quick test it can be replaced by a 2.2uF capacitor which should be available. Use a tantalum capacitor if possible, for final replacement, they last much longer (and are used on late models of the E35). |
Roman Dubravsky
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, February 15, 2005 - 01:30 am: |
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... the shutter sometimes stays open and sometimes closes as soon as the button is released ...
I repaired YE for the same problem just yesterday. It was caused by the famous "pad". It was gummed, disintegrated. Slide contacts sometimes reach to third position*), sometimes not.
*)
First position - check overexposure, red light
Second positon - check exposure longer than 1/30s, yellow light
Third position - shutter timing
"Timing" capacitor can have lower capacity than Winfied write too. I have two my own YEs. One GTN have a 1.0uF capacitor, next GS have 1.5uF. It is variable, but 2.2uF is probably most common. |
John
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, February 25, 2005 - 02:36 am: |
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Thanks for all the info guys, I finally had no option but to strip it down and check.
I found that this camera has been repaired before - the pad is in great shape and made from what I can only describe a a very firm silicon type rubber, plus the capacitor has been changed to a tantalum bead, but it is not marked with a value.
I also found that, althought the tracks are very clean, the sliding finger furthest from the lens was not making full contact with the tracks, which may explain the flickering lights. After taking this area apart, cleaning and carefully reprofiling the fingers I have put it all back together for testing.
I now have very steady over/under lights in the correct sequence and the yellow goes out before the shutter fires. Long exposures stay open after I release the shutter button and seem to progress in doubling steps for each reduction in aperture. so looking good.
I have one final question - when should the "click" happen in the winding cycle? Before I worked on it this used to happen almost as soon as the wind lever was moved - now, it happens on the return stroke of the lever, is that right? Everything works as it should and the shutter button "just" latches down on firing (as recommended on several websites), but have I screwed up the sequence somehow?
Any help most gratefully received. |
Winfried
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, February 25, 2005 - 07:40 am: |
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The 'clunk' should be audible on the first stroke of the advance lever, i.e. when you start pushing it, at approx. 1/3 of its forward travel.
There is a latch under the bottom plate which keeps the lower part of the shutter release shaft (i.e. the slide switch shaft) in the lower position after pressing the shutter button. It should be released as soon as the advance shaft is turned. Maybe you have to rebend the latch lever a bit. |
John
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, February 25, 2005 - 09:29 am: |
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Winfried,
Yet again you save the day - I am learning so much here!
There is some play where the release shaft fits on its pivot so that the cumulative tolerances prevented release in the first part of the stroke - on the return, the tolerances were self-cancelling, so it tripped.
The quick and dirty answer was to bend the little cam on the rotary part so that it kicks the lever a bit further (I don't even want to think about making a bushing for the lever!).
So it is all now back together and I find I have yet another problem! I am left with a small piece of thin black card, about 10mm x 6mm with a 2.5mm hole in the middle - where on earth did that fall out of? Aaarrgghh!!!
I think my next adventure will be either skydiving, or an Electro Pro with a sad shutter - I wonder which is easier on the nerves? |
Winfried
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, February 25, 2005 - 04:23 pm: |
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Maybe this piece of black cardboard is just an nternal cover for the film rewind release button? I have not seen this on Electros but on other cameras.
Hope your day is totally saved now... |
John
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, February 26, 2005 - 04:38 am: |
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Winfrieed,
I had horrors thinking it was part of the RF assembly, but having looked at many sites with pics of that, I don't think it is. I have no idea where it came from, other than it was definitely inside the top cover somewhere.
Ah well - if it works without it.....
Thanks for all your help - I hope I come out of the Pro experience in one piece! |
Winfried
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, February 26, 2005 - 09:49 am: |
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On some cameras there is an "aperture" thing inside the rangefinder. It usually is attached to the rather big convex lens which "separates" the two chambers of the rf/vf assembly, and the purpose is to block unwanted light, reflection etc which might be visible around the rangefinder spot.
I just have two Electros semi-dismantled on my bench and I will have a look later. |
Winfried
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, February 26, 2005 - 12:48 pm: |
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Just checked it and there is a piece of black cardboard glued to this lens element I mentioned. It is glued to the surface towards the tiny lens which sits on a swing arm. It is not important for proper operation of the rangefinder however it may keep off some unwanted reflections inside the viewfinder. |
John
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, February 28, 2005 - 09:14 am: |
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Winfried
Yet again you amaze me! I can see some reflections around the rf spot now you mention it. Which face of the convex lens is it fixed to - nearest the small lens on the swing arm or the other side? Also, any ideas what sort of glue to use?
Incidentally, my shutter is still playing up.
This is particularly noticeable at f16 in low light. If I select f8 with a yellow light, changing to f11 will produce a shutter time that is about twice f8. However, if I now select f16, the shutter sits open for an absolute age, normally until I get tired of timing it and decide to change the shutter. I noticed that sometimes at f1.7, the shutter does not open correctly, particularly with a red light.
Further, sometimes when I have a correct exposure (ie no lights) the shutter misfires, often twice in a row. Looking throught the lens at an even light source suggests that the shutter is either firing at something faster that 1/500, or it is not opening fully (my old eyes can't quite determine which).
I took the lens off and checked the shutter blades, which are clean and dry.
I was leaning towards the aperture contact rings - having done some more tests today in bright light, I have had a range of wacky results at f16 from underexposed at 1000asa while f11 was over (really!) to 2 seconds at 400asa to 1/500 at 25asa. However, I checked the contacts inside the lens housing and they are clean and making contact with the tracks.
Now I find that in 40 or so releases of the shutter at f16, I get one or two at 1/500 and one or two at 36 seconds+, but the majority at around 1/2 sec, which is what I had expected given the light level.
I'm completely baffled. |
Winfried
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, February 28, 2005 - 02:18 pm: |
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The black piece is glued between the big lens element and the small lens element on a swing arm. I think you can use virtually any glue which is suitable for non-porous surfaces. When using superglue, NEVER apply it directly.
Believe me, even if contacts look perfectly clean they sometimes are NOT. My job as an electronic design engineer would be much easier if bad contacts were so easy to detect... I would strongly recommend cleaning the contacts with electronic contact cleaner, use a 'tuner spray' if possible. Moisten a q-tip with this fluid and wipe the contacts gently several times. It seems as if the f/16 contact is dirty since you get such a leap of exposure time when changing from f/11 to f/16. |
John
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, March 01, 2005 - 03:12 am: |
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Winfried,
If I had read your post correctly, I would have realised where to stick it - sorry! Superglue - YUK! Presumably the hole should be concentric with the hole in the curved lens?
I wondered about the tracks, but have cleaned them and the sliding fingers, but to no effect. I also cleaned the track under the resistor chain around the aperture ring. Interestingly, the f16 problem is now fully reproducible, si I decided to take resistance readings from the resistor chain, but do not know what the values should be, so it has not helped much. They run as follows, staring at the top (f1.7) 1.7, 2.2, 2.2, 1.6, 0.9, 0.5, 0.18, 0.4 - all in Ohms
I'm a bit worried about the penultimate resistor as the value does not seem consistent - it sometimes measures 0.18 Ohms, sometimes 180 Ohms. I don't think this is my meter or measuring technique, and I have no idea why that happened, but it would explain the situation if it has gone bad in some way - do you have standard figures for the resistors? |
Winfried
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, March 01, 2005 - 04:03 am: |
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Of course the hole in the black piece should line up with the hole in the lens.
May you can find the nominal resistor values in the schematics provided on
http://www.provins.org.uk
Otherwise, if I remember it correctly the resistors have a color code. If you tell me the sequence of colored rings or dots I should be able to figure out the value. However your inconstistent readings could be due to a bad solder point of the resistor(s).
At least you finally reached the point where the error is reproducible. We once noticed an erratic malfunction in one of our modules but could not find the cause since it occured just once in several days. Months later we found a module with consistent malfunction and could locate the problem. |
Winfried
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, March 01, 2005 - 04:37 am: |
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I am afraid that your readings when measuring the resistors are of little use - it is impossible to measure a resistor correctly when it is still connected to other parts, especially to transistors etc. The schematics provided by Roger only show the whole resistor bank but no values for each resistor. So the only way is to check the color codes. You also could try to lift the pc board with the resistors and resolder the solder points and/or check the tracks for continuity. Beware, in some odd cases the pressure of the measuring tip can make a broken solder point work again - but only until you remove the tip. |
John
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, March 01, 2005 - 05:04 am: |
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I thought that may be the case - I will try resoldering each connection point and see if that makes any difference.
I have the colour codes and will try to work them out myself before offering you that task.
Thanks again for your help. |
John
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, March 02, 2005 - 02:54 am: |
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Right!
I have spent so much time on this and it's still two steps forward, three back!
Following advice here and on the rangefinder forum, I have now checked the shutter blades (clean & dry) and resoldered all the connections on the resistor chain connected with the aperture ring. Yes, stupid boy, I forgot that I can't measure resistance while the part is still in circuit (doh!). Anyway, since f16 was causing the problem, logic suggested checking the last resistor in the chain. I removed it and it measures 1.14 Ohms (so what?). I substituted a piece of plain wire to see if it made much difference to the f11 shutter speed - interesting! At a 2 second exposure @ f11, I now got around 3 seconds @ f16, probably explained by the fact that the resistor value is relatively low anyway. So resistor back in and I get 4 seconds - whoohoo!
This sets me to thinking and I decide to check the solder joints on the pc board with the (already) replaced capacitor on. Lo and behold, one or two dry joints and the capacitor has a small crack at the top of the -ve leg. Next move is swap the capacitor, but it is unmarked - following conventional wisdom, this is usually 2.2 or 3.3 microfarad. Tried both these values, but ended up with a completely random shutter (arrgghh!), so original back in until I can get some other values to try.
Wait a minute! It's all working PROVIDING I have all the screws in that hold the meter circuit in the body - wow! (I wonder if there is a return path through the frame?) So I put it all back together and give the shutter a good few dozen tries at different asa figures and the difference between f11 and f16 is just about double every time - go to bed a happy boy.
Wake up this morning and show her indoors how clever I am only to find that the shutter is as random as ever (grrr!). So I'm back to square minus one!
I'm starting to think that the IC is dodgy and only works correctly when it is warm - ie above a certain temperature - this is backed by the fact that the loger held the body this morning, the better it worked.
Anyone got any bright ideas? |
John
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, March 03, 2005 - 02:09 am: |
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Winfied,
If you read this, I am now certain that the problem is temperature dependant - cold camera = random shutter speeds. Warm it up to body temperature and everything works as it should.
I will again check the shutter for being gummed up, but beyond that, I think it has to be the electronics. |
Roman Dubravsky
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, March 03, 2005 - 08:39 am: |
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Ad aperture measuring resistors.
Their nominaly values are:
f 1.7 ... 90 Ohm
f 2 ... 10 Ohm
f 2.8 ... 30 Ohm
f 4 ... 65 Ohm
f 5.6 ... 115 Ohm
f 8 ... 175 Ohm
f 11 ... 215 Ohm
f 16 ... 160 Ohm
Total 860 Ohm |
John
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, March 04, 2005 - 02:53 am: |
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Roman,
That's very interesting, what model does that refer to?
According to the service manual, a GSN with the later type of control module (no large resistor on the back) should have a total value in the aperture chain of 10k ohms - somewhat different to your total. |
John
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, March 04, 2005 - 06:42 am: |
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Roman - It's OK, I see that those values are for the GS and similar models with the type 368 or 408 controller.
The later GSN/GTN with the type 415 controller use different values that add up to 10K ohms, but I have to work out the values from the colour code. |
Roman Dubravsky
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, March 07, 2005 - 07:54 am: |
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Hello John,
It is interesting information. I thought than every resistors chains are equal and all types of electronics board are changeable. So I'm preparing to change bad board with IC (415 type) in YE GTN to good one type 408 from YE GS. According to your info, I will need to balance relation between R8, R9 and resistors chain too. |
John
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, March 08, 2005 - 01:44 am: |
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Roman,
According to the service manual, you can use either of the early control boards (368 and 408) with the early resistor chain, but to use a 415, you must have the later resistor set with a total value of 10k ohms.
So, for your situation, you must change the resistor chain to the one from the GS to maintain the correct exposure. I think the only downside to this is that, while changing the whole board is easy, you will be going from gold to tinned contacts. A little contact cleaner fluid/lubricant may be a good idea.
Also, be aware that the 408 board has reversed polarity for the timing capacitor compared to the other 2 types - just make sure you connect the yellow & orange wires to the correct (-ve) terminal on the board.
Finally, don't forget that if you are changing the whole controller assembly that the rear mounting post is different with the later type - if you are just changing the pcb, this should not be a problem. |
Roman Dubravsky
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, March 10, 2005 - 03:32 am: |
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Hello,
As I'm thinkig about it, higher values of resistors in voltage divider (R8, R9 and aperture measuring chain) can cause one failure which occurs relatively often in last Electros. It is unstability or malfunction of metering when light is low and aperture is high. Voltage divider with higher values of resistors is "weak". If Tr2 have low empowering coefficient, its base current (emmitor current of Tr1) changes relations into voltage divider, voltage on base go down, base current is insufficient, Tr2 never close, shutter stay opened.
Can my idea be right? |
M.Yonezawa
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, March 11, 2005 - 02:31 am: |
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Hello Roman;
Yes it is possible. I think so too.
And I wonder about NFB(negative feedback) effect on this circuit.
When the base current of Tr1 begin to flow this current act as leakage from the capacitor.
The voltage rising become slow. It's a kind of NFB.
The hfe (amplify factor) of some transistor depend on its collector current value.
(Often, higher current - lower hfe.) This may act as NFB.
All of those NFB effect let the circuit stay balanced state.
Balanced means not completely shut AND not completly conducted.
(It act like analogue amplifier not a electronic switch.)
So we sometimes hear something ringing in the shutter assembly on that situation.
It is from solenoid driven by oscillation current.
M.Yonezawa |
Roman Dubravsky
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, March 11, 2005 - 07:30 am: |
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Hello,
Yas, I heard it too. In fact, often are in circuits several capacitors, whose not plotted in chart.
Roman |
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