| Author |
Message |
    
Zelandeth
Tinkerer
Username: Zelandeth
Post Number: 1
Registered: 06-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, June 24, 2009 - 11:28 am: | 
|
A new poster here, who's been chasing this problem around for a while now.
Picked up this T3 from a charity shop a year or so back now for next to nothing...Then forgot about it for a while due to work getting manic and having discovered the PX675 conundrum.
Found it again, and finally got around to getting some 675ZA zinc-air cells, and have been somewhat disappointed to find that it still refuses to play ball - even having left the cells a good long while to stabilise.
Testing as per the manual shows no response.
Having read about the battery terminal maladies which often affect these cameras, that was checked at, and appears to be innocent - it's clean and is still showing good levels of "springiness" and is holding the cells in place well.
Some further investigation revealed that the meter will react if the film speed is cranked up - so there is power definitely getting from the battery to the meter. Is it possible that someone's tried to adjust the camera previously for alkaline batteries, but has "twiddled" the adjusters without having a clue what they're doing? As a restorer of vintage radios and televisions - I'm no stranger to the effects of this phenomenon! For reference, the meter sits bang on the check mark with the controls set to ASA3200 and 2s on new 675ZA's. On alkalines, that seems to be closer to the ASA1600 - though it's at the top of the check mark there.
Thoughts folks? Is there any hope of me sorting out this lovely camera? I'd really love to put it back into regular service - but I'm by no means good enough to eyeball light levels, and as yet at least, don't own a separate light meter. |
Hovaness
Tinkerer
Username: Hovaness
Post Number: 78
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, June 24, 2009 - 03:50 pm: |
|
The meter adjustment potentiometers are easily accessible on top of the prism. There is also a shutter dial timing cable adjustment that may be suspect, but this is easy to reach too. It is probably worth taking the top off and twiddling with the meter adjustments. |
Zelandeth
Tinkerer
Username: Zelandeth
Post Number: 2
Registered: 06-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, June 24, 2009 - 04:04 pm: |
|
Thanks for the quick response.
I'll see if I can figure out how to get into the camera tomorrow evening. Film speed selection and advance lever look most likely candidates to put up a fight as I've no idea how to separate them...if anyone's got a proceedure for the removal of the upper casing of this camera in terms that I'm likely to understand, I'd be grateful if you could point me to it. I know there was one describing the complete disassembly to get to the battery compartment - don't know quite how much of that I'd need to use though, and I can't remember for the life of me where it was. While dismantling cameras is a bit of a new thing for me - I'm no stranger to taking apart things which can be a bit on the complicated side, so I do realise what I'm letting myself in for at least, and will be quite sure to go no further than I'm completely sure I can get back from - this camera's too good to wreck.
When twiddling said adjustments - is there anything I can use as a reference to get the value shown "in the ballpark" so to speak? e.g a 60W lightbulb at 1 metre at ASA "x" and shutter speed "y" should put the needle about here? |
Gez
Tinkerer
Username: Gez
Post Number: 109
Registered: 09-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, June 25, 2009 - 05:37 am: |
|
The meter coupling cord moves the whole galvanometer, so the needle will appear to move into the metering range when set to the extremes of 3200asa and 1 sec. However, I suspect that the black wire from the battery spring to the prism circuit board is either corroded or come detached at either end. This is a common fault with the T3 and T3N.
Rick has some excellent notes on the T, T2 and A3. He may have contacted you already? The A3 notes are suitable for removing the top cover of a T3, but removing the front panel/mirror box of a T3 presents some difficulties. You may not need to go that far. |
Zelandeth
Tinkerer
Username: Zelandeth
Post Number: 4
Registered: 06-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, June 25, 2009 - 02:29 pm: |
|
Gez,
Thanks for the tips there.
Good theory on the meters apparent movement - but on this occasion I'm reasonably certain this isn't the case. As it reacts to the battery check or exposure to light on these settings. It seems as though the sensitvity of the meter is simply far lower than it should be.
I suppose there's the possiblity of that wire being corroded and high impedance though still conducting - or a high impedance fault in the switch.
Think if it comes down to removing the mirror box and such that it might well be a job that I'd save up to pay someone to do, as I don't think I'd trust myself to delve that deeply! |
Gez
Tinkerer
Username: Gez
Post Number: 110
Registered: 09-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, June 25, 2009 - 04:36 pm: |
|
Once the top cover is off you will be able to test the resistance of the black negative wire. The T3 uses a positive earth.
From what you say it would appear that the camera has been 'worked' on and is not in its original condition. The 2 pots on the prism board have probably been altered but more likely the adjustable screw controlling the tension of the coupling cord has also been changed. |
Teddyrobo
Tinkerer
Username: Teddyrobo
Post Number: 1
Registered: 03-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, March 09, 2010 - 07:09 pm: |
|
Zelandeth, did you ever get your light meter fixed? I just picked up a T-3 and the EXACT thing you describe is happening to me. At first I thought the batteries were shot, so I picked up some hearing aid batteries to check. I get no response unless I crank up the speed to 3200 and 1/2/4s
What is actually going on? When I run the battery test it reacts to the batteries so there is some kind of contact. Any help would be greatly appreciated  |
M_currie
Tinkerer
Username: M_currie
Post Number: 220
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, March 10, 2010 - 08:07 am: |
|
Especially if you think the camera has been worked on, you should try higher voltage batteries first before doing much else, because there's a possibility someone did the compensation for silver-oxide or alkaline, and if it was done right, you may be in luck.
It seems unlikely that recalibrating would make that much difference, but the T-3 is pretty sensitive to voltage. Even hearing aid batteries require a 2/3 stop offset, and alkalines or silver oxides make compensation with the ASA dial almost impossible, so it's worth a look first.
I had a similar problem with a Konica rangefinder and found that the wiring to the battery box was badly corroded. Still some contact, but high resistance. So if you don't get good results from a battery swap, I think that battery wiring is the next step. |
Gez
Tinkerer
Username: Gez
Post Number: 185
Registered: 09-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, March 10, 2010 - 12:45 pm: |
|
Sometimes the free movement of the meter needle can be restricted by the auto exposure mechanism. Check that the black ring visible at the back of the mount flange is moving freely and is connected to the 2 chrome forks at either side. |
Teddyrobo
Tinkerer
Username: Teddyrobo
Post Number: 2
Registered: 03-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, March 10, 2010 - 02:59 pm: |
|
Thanks for the advice, I don't think the camera has been worked on because when I bought the camera it still had 675 photo batteries in it, which I believe are the mercury batteries. I'll try and check about the AE mechanism. Thanks for the help everyone. |
