Weird GSN or is it me?

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Belgium

Thierry from Flanders
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Hello I'm Thierry, I live in Belgium and am new to your site :angel:

Last week I bought a Electro 35 GSN for about 30$.
I have the impression it was very rarely used.
The pad is intact with sharp edges and it's made out of a, yellow-orange, a bit transluscent material.
I found the original battery inside(TR164), still working fine.
With this battery I tested the exposuretime: with the CDS-cell completely obscured and f 16 I get a time beyond 60seconds.
The same test performed with a LR44, cardboard lining and a spring gives me 1 second. And before the shutter closes I hear a whining sound(I hear nothing with the TR164) 😕

Euh.... HELP.....please....someone... 🙂
 
Hm, if that spring is corroded at the edges, i could understand the reasoning, greyhoundman. But a clean netal spring of that size should not have any considerable electric resistance.

Thierry... I have two gsn's, one i use with an original PX...whatever mercury battery, the other one is adapted to a smaller silver-oxide.
I hear the whining sound with BOTH batteries and BOTH cameras, if the sh speed is in the range of tens of seconds. Just like when a flash unit reloads, right?

In fact it IS the same as a flash unit reloading. The shutter is timed with a capacitor which is charging up slowly. The bigger the resistance (of the photodiode/meter), the lower the voltage on the capacitor thus the slower it can be charged. When it's fully charged, the transistor is opened for closing the shutter. At the latest stage of loading one can hear the whining sound, but only if it loads very slowly.

I have no idea why you don't hear the same with the other battery, and why you get a different reading. Can it be maybe, that the old mercury battery is dying?
 
Belgium said:
Hello I'm Thierry, I live in Belgium and am new to your site :angel:

Last week I bought a Electro 35 GSN for about 30$.
I have the impression it was very rarely used.

The same test performed with a LR44, cardboard lining and a spring gives me 1 second. And before the shutter closes I hear a whining sound(I hear nothing with the TR164) 😕

Euh.... HELP.....please....someone... 🙂
Click to expand...

If the spring is not lined up correctly you can get a bad connection. This happened to me recently. I jiggered the spring around and the battery check light sprang to full light.
Before that it was dim.
 
Hm,weird. I went right now to check on my gsn's. This time only the one using the mercury battery makes the whining sound. The silver-oxide does not do it whatever i would do.
They both give the same exposure however.
Sorry for my previous post - i'm sure it DID behave the same way but now it does not.
 
Belgium:

The original battery for the Electro-35 was made up out of a series of smaller 4 mercury cells soldered together. If one or more of the cells is dead or unacceptabley weak, you may be getting only partial functioanlity from the entire battery.

I suggest you take the old battery check the output voltage. I believe it was originally rated at 5.4 volts. The camera is not supposed to be sensitive to minor variations in voltage, but I am sure that if there is a significant voltage drop, it will not work properly.

-Paul
 
Hello Guys,

Thanks for all your quick responses and valuable help 🙂

I did some tests:

1) The voltage of the mercurycell is 5.33V, that of the LR44 is 5.64V
2) With the mercurycell I tried the maximum exposuretime.
I blocked the CDS with my finger, f 16, pushed the release, the yellow light came on, the yellow light went out and a bit futher the shutter opened and I released the releaseknob.
But after 3 minutes I got bored the shutter was still open, I took my finger away from the CDS and immediately the shutter closed.
(My GSN is weird 🙂 I've read that the maximum for the GSN was about 30s 😕 )
3) I took my trusty Olympus OM2n and put him on 100ASA as I did on the GSN.
I took a piece of wall inside the house as a referencetarget, the lightconditions are stable because we have stable grey weather for the moment.
On f1.7 the red light is on, on f2 the red is out, when I reach f8 the yellow comes on. So I presume that on f8 I've reached 1/30s.
Under the same conditions my OM2 gives me f8 and 1/2s.
I've tried this with both batteries in the GSN and get the same result.
The GSN is underexposing although a lot of things seem to work normal, only a bit weird 😀

Any clues someone??
 
Hello Greyhoundman,

You're right.
I do not know exactly how the system works, but it's possible that the old battery takes longer to charge the capacitor.

But the third test I did was with both, mercury and the LR44.
They both underexpose in the same way.
 
I didn't mention that, but I already shot a film. With the LR44 inside.
The exposures outside are good when shot in bright conditions, but inside they're really underexposed, dark and grey.

Could it be a problem with the slidercontacts, I've just opened the bottom.
 
You really suspect those sliders? That's a major operation.
But I have trust in your experience 🙂
Just had a look at Matt Denton's site.
Is that the best site and, or way to follow?
Looks "dangerous", are there pieces jumping out never to be found again?

I want to get my GSN back to normal life, so I have to do it
 
It works like it should do.
The yellow light goes out and then opens the shutter.
The shutter closes when the releaseknob has travelled 2/3 up.

And I will be very carefull, I'm a bit used to that because I work in the nuclear sector. 😉

You know I very much like your foottext 😀
 
Hello, I'm back from cleaning the contacts in the lensbarrel.
Everything looked clean and the contacts gently pushed the upperpiece loose when I loosened the three small screws.
Everything was cleaned with alcohol and I bent the contacts a little bit more.

And...... no result

I also tried a bit of contactcleaner on the contacts from the shutterrelease-rod. Not easy to reach from the bottom, and I'm not sure they got some of the spray.

I'm open for further suggestions ( my first major surgery went well 🙂 )

When cleaning the rangefinderwindow I found the capacitor, somenone knows what value this one is ?
 
Belgium said:
I did some tests:

1) The voltage of the mercurycell is 5.33V, that of the LR44 is 5.64V
2) With the mercurycell I tried the maximum exposuretime.
I blocked the CDS with my finger, f 16, pushed the release, the yellow light came on, the yellow light went out and a bit futher the shutter opened and I released the releaseknob.
But after 3 minutes I got bored the shutter was still open, I took my finger away from the CDS and immediately the shutter closed.
(My GSN is weird 🙂 I've read that the maximum for the GSN was about 30s 😕 )
3) I took my trusty Olympus OM2n and put him on 100ASA as I did on the GSN.
I took a piece of wall inside the house as a referencetarget, the lightconditions are stable because we have stable grey weather for the moment.
On f1.7 the red light is on, on f2 the red is out, when I reach f8 the yellow comes on. So I presume that on f8 I've reached 1/30s.
Under the same conditions my OM2 gives me f8 and 1/2s.
I've tried this with both batteries in the GSN and get the same result.
The GSN is underexposing although a lot of things seem to work normal, only a bit weird 😀

Any clues someone??
Click to expand...

According to the service manual, the camera needs 5.4v minimum to work correctly - did you check your voltages under load, or straight off the battery?

As to max exposure time, I have both GT and GTN models that will go beyond 2 mins with the cell covered - there may be something here about negative feedback in the control circuit, such that the transistor that closes the shutter never gets activated - I got this from a guy in Japan who gave an eloquent explanation that was beyond my electronics knowledge. I gather it can particularly happen at lower voltages. My GSN always does this at f16 in anything other than bright light - I have no idea why.

Once the yellow light comes on, you are probably at a speed slower than 1/30 - it is a warning of camera shake, so it could have been 1/15 or 1/8, there is no way of knowing. So the readings could have been within 1 or 2 stops of each other.

I'm assuming that the pad is OK on your camera? This should always be the first check, followed by the sliding contacts and those inside the lens that you have already cleaned. The other possible cause of trouble is the capacitor - I have a couple that look like yours, but do not know what the value is. I have seen values between 1.9uF and 4.3uF on different cameras. Most people try a 2.2uF tantalum as first replacement, followed by a 3.3uf if that gives short exposures.

I suppose it is just possible that one of the transistors in the controller is getting tired, but that should be a consistent problem - have you checked to see if this is a temperature related problem?

You could also try the classic repair forum - Winfried over there knows more than most about the Yashica range and Clive is an ex Yashica repairman.

Hope that helps!
 
I would suggest to visit Roger Provins website. He has the full electronic schematics for YE 35 series in his page, and has made a wonderfull job explaining how it works. The capacitors vary in their value depending on age, temperature, quality, etc. so unsoldering it from the PC board and checking if it´s OK is a good way to start. In all YE 35 I will check electroics first before attempting to dismantle the camera for major surgery.
 
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