| Author |
Message |
    
Smasher
Tinkerer
Username: Smasher
Post Number: 7
Registered: 12-2008
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, January 11, 2010 - 09:48 am: | 
|
Hi, folks.
I've got a Konica Autoreflex T (not T2) with non-functioning meter. This is a great camera, and I'd love to get the meter/aperture linkage working correctly.
I've checked the meter needle assembly, and it seems to work. (Needle moves when checking resistance.) Not sure how to test whether the CdS is working, or how to text the power switch.
Also (stupid me) when disassembling the camera, I didn't keep track of where and how the needle ass'y links to the shutter/ASA dial, and need to reset it to the correct adjustment.
I've checked and read the section on the Autoreflex T in the Tomosy book, but he doesn't explicitly talk about the meter needle to shutter/ASA linkage. Can anybody offer a pointer here?
Thanks in advance.... |
Gez
Tinkerer
Username: Gez
Post Number: 168
Registered: 09-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, January 11, 2010 - 10:56 am: |
|
There are substantial differences in the internals of the T when compared to the T2, so your confusion is understandable, particularly as Tomosy is actually describing the T2 not the original model T of 1969!
It would be helpful to know how far into the disassembly you have got. Did you just open the camera to replace the black wire to the battery compartment and also to replace the rubber bumper holding the tensioning latch in place??
Provided the metering cord hasn't been cut or detached from either the galvanometer pulley or the shutter speed disk, the metering is fairly easy to reset to within +/- 1 stop, but to adjust to +/- 1/2 a stop you will need a standard light source. |
Smasher
Tinkerer
Username: Smasher
Post Number: 8
Registered: 12-2008
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, January 11, 2010 - 11:48 am: |
|
Hi, Gez. Thanks for the info.
I haven't taken out the mirror assembly. I took off the top plate (using a pin to keep the shutter speed and ASA ring properly aligned at 1/125 and 100ASA) and then (and here's where I ran into trouble) removed the top plate of the galvanometer assembly, which promptly dislodged the galvanometer adjustment.
I don't see any corrosion in the battery compartment at all, and really don't want to pull the mirror box unless I determine without a doubt that the connectors are corroded.
The meter switch looks good, too. No corrosion that I can see. As I understand it, the corrosion problem was mainly found on later models (T2 and T3?) due to bad soldering flux at the battery box.
I've also checked the forks on either side of the lens mount--the ones that couple the meter reading to the aperture setting. Both are correctly in place. |
Gez
Tinkerer
Username: Gez
Post Number: 169
Registered: 09-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, January 11, 2010 - 02:43 pm: |
|
You removed the plastic circuit board-type plate that holds the galvanometer top pivot and the aperture scale mask, correct? The sudden release of tension has probably caused the galvanometer housing to jump out of its bottom pivot?
First off, keep the shutter speed and asa disks properly aligned with the pin, but let off as much cord tension as possible by setting to 1/1000 sec and 25 asa. To do this you may find it easier to reassemble the s/s knob.
Reseat the galvanometer in its bottom hole and carefully reposition the top circuit board so that the galvanometer is secure and aperture scale mask isn't bent in any way. This is easier to do if the prism is out of the way, but the less disassembly the better.
Use a small torch and look down the gap between the aperture scale and the geared sector of the galvanometer housing. The last cog of the gear should align with the bottom ceramic stop bar, (the cream colored bar that stops the meter needle going off scale, there is one at the top also). This is equivalent to a setting of 1/1000 sec and 25 asa, without a lens attached.
If you have difficulty check that the metering cord isn't snagged and is running smoothly thru all the pulleys, and also that the coil spring near the on/off switch is hooked onto the adjustment slider.
That's how I would do a T2, but the galvanometer circuit board in the T is bigger, so it may be hard to see what's going on.
PS watch out for a brass washer on top of the galvanometer. |
Rick_oleson
Tinkerer
Username: Rick_oleson
Post Number: 1038
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, January 11, 2010 - 08:51 pm: |
|
In the Konica T-T3 series, the most common cause of a dead meter is the battery terminal breaking out of the battery box. Did you check that the metal button in the bottom of the battery box still feels stiff and springy? It's just attached with a pair of plastic studs that often break under the constant strain of having a battery pressing against it.
Unfortunately, what sounds like it would be a simple fix requires a major disassembly, just because Konica decided to make the battery box removable only after the mirror box is removed from the chassis. |
Smasher
Tinkerer
Username: Smasher
Post Number: 9
Registered: 12-2008
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, January 12, 2010 - 12:23 am: |
|
Thanks, Gez and Rick!
Gez: Yes, you're describing exactly what I did, and how it went wrong. This was exactly what I needed to know. I'll give this a shot in the next couple of days.
Rick: I did check the springyness of the contact at the bottom of the battery box; it seems OK. But even with new batteries, the power switch doesn't seem to do anything. I'll take another look at the schematic to see if I can make sense of it. |
Rick_oleson
Tinkerer
Username: Rick_oleson
Post Number: 1039
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, January 12, 2010 - 09:42 pm: |
|
The second most common cause would be a corroded & broken wire at the battery terminal. This (unlike the terminal separation issue) is not a Konica problem per se, it happens to all cameras. It always seems to affect the wire attached to the (-) battery terminal, and always at the end closest to the battery... for this reason I expect that galvanic corrosion is involved. I don't know an easy way to confirm this, as the affected part of the wire is hidden up above the battery box, you still have to pull the mirror box to reach it. The corroded wire can't be resoldered, you'll have to cut it back at least an inch or two before you find good copper you can solder to (if this is the problem).
I have sketches of the T disassembly that I'll be happy to share if you'd like a copy. email me at [email protected] |
Bossman
Tinkerer
Username: Bossman
Post Number: 112
Registered: 02-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, January 13, 2010 - 12:17 am: |
|
I have had many "T"'s that lost circuit ground at the meter housing itself. I always solved that by soldering a small flexable wire from the meter structure to a good ground close by. Most of the time, that took care of either an erratic meter or an inop one (after checking the battery well and wiring as Rick so aptly pointed out). Art....www.flcamerarepair.com |
Ron_g
Tinkerer
Username: Ron_g
Post Number: 6
Registered: 07-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, March 18, 2010 - 11:00 am: |
|
I have a T2 that I have been working on and I just have to say that the post by "Gez" got me on the right track and I want to thank you for taking the time to post it for us to refer to.I never would have figured out the ASA/Galvanometer calibration but after that most everything else fell into place.Thanks to all.Ron G |
