| Author |
Message |
    
Rob
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, February 22, 2006 - 10:05 am: | 
|
I picked up a Praktica Super TL with a problematic light meter. When the metering button is depressed, the needle drops right down to the bottom right away. No changes in shutter speed or aperture make a difference. I figure if the meter was dead, the needle wouldn't move. Is it possible something inside is blocking light from getting to the sensor? |
Stuart Willis
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, February 22, 2006 - 06:15 pm: |
|
To your closing question. It is most unlikely.
Current from the battery routes via the light-cell to the galvometer. Resistance within the cell changes according to the intensity of light falling upon it. If the cell is short circuit (ie "dead") then the meter will see no resistance and the needle will be deflect unimpeded.
The metering circuitry is on a small pcb around the film-rewind knob - and is easily accessed when the top-plae is removed. It is just possible that the light-cell is OK and that there is a dry-joint or detached wire.
On the aforesaid pcb you will see three trimpots.
Do not adjust any of them in any way. There is a setup procdure but you will never establish the proper settings again unless with the specific set-up data on hand. |
Rob
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, February 22, 2006 - 11:03 pm: |
|
Thank you Stuart.
I haven't had the top off of one of these yet, so probably on the weekend I'll have a go at it. I would appreciate any further info on removing the top plate in case there are any surprises. |
Lars
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, February 23, 2006 - 01:16 am: |
|
Rob,
Prepare yourself for a major battle with the return-spring for the frame counter. It is almost(?) impossible to put back in place. It springs open when you lift the top cover. For some reason, the inner-most point will not stay attached when you try to wind it again. I have been struggling with this now (on and off) for over a year, and still havn´t found a working method.
Any advise is welcome.
Otherwise it is quite easy to work on. |
Rob
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, February 23, 2006 - 11:54 am: |
|
Thank you Lars.
I'm not worried about the return spring. It's a nice toy, but it's not necessary. I've had other cameras where the frame counter didn't work. I still use them. Maybe I'll stumble across something for you along the way. |
Steve
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, February 25, 2006 - 07:22 am: |
|
The article on this site re. the MTL-3 will get you under the top cover without problems.
Have had 3 or 4 of these apart, and haven't had a problem with the frame-counter spring. The outer end of the spring fits on a post, and the inner end stays attached to whatever it is attached to on the dial! |
Steve
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, February 26, 2006 - 02:33 am: |
|
I had thought this was the same as the later metal-shuttered Super TL models. Have since discovered this is probably not the case. Please ignore previous message. Apologies!!! |
