Contax 139Q Light Meter Calibration

[Mrfrst]

I've looked high and low for this information, but I haven't been able to find out how the light meter on a 139Q is calibrated - mine is reading one stop too fast (underexposure). I see three trim pots on top of the pentaprism (labled 1 3 and 5 I believe), and I presume that one of these adjusts the offset for the main light meter (are the other two slope and TTL flash offset?).

Also, if you have any ideas about troubleshooting TTL flash metering, I'd love to hear about it - my TLA 360, which works fine on an RTS II, just fires at full power on TTL mode with my 139.

Does any one have a service manual?

 

[ic-racer]

Do you have the service manual? Only certain things can be adjusted.

 

[ic-racer]

BTW the Yashica FX-3 has some mechanical similarities to the 139Q (and takes the same lenses) but I think it is easier to service and easier to adjust the meter.

(there was a url link here which no longer exists)

 

[Mrfrst]

Huh, so it sounds like the offset can't be adjusted... that means a problem with the ISO selection reading or the minimum aperture reading the I suppose. Those pages are very useful, thanks. If the manual is available somewhere online, can you send it to me?

 

[mynewcolour]

Also, if you have any ideas about troubleshooting TTL flash metering, I'd love to hear about it - my TLA 360, which works fine on an RTS II, just fires at full power on TTL mode with my 139.

The TLA 360 is of a generation after the TLA 20 and 30 and wont meter with that camera body.

 

[Mrfrst]

Hmm, interesting thought. The 360 TTL function works great with my RTS II, which is of the same vintage and has the same contacts on the top. Do you know for sure that it's not compatible?

 

[mynewcolour]

Yeah: info found online.

I found a used TLA 360 for pennies so thought I'd try it with my 139q - no joy.

The RTS II came to market after the 139q I believe.

 

[Mrfrst]

Okay, that's good to know. Too bad, but at least I can put the issue to rest.

Here are some shots of the some relevant circuitry by the way - I haven't found many sources for this online, so now there's this

I also found that you can access the shutter damper flywheel without removing the top cover - just remove the bottom cover, and the lower part of the mirror box shroud (as seen here). Useful for quieting a squeaky flywheel like mine had when I got it.

 

[Mrfrst]

Also, contrary to what I've ready elsewhere, the top cover of the 139Q is made of plastic rather than metal, just like the FX-D. And the camera is really in a different class altogether than the RTS, where everything you touch is made of metal. Most of the switchwork on is plastic and much cheaper feeling on the 139. Really, now that I know that the TLA360 doesn't work in TTL mode with the 139, I prefer most of the design features of the FX-D, like its shutter speed control ring that can be operated with the other hand on the focusing ring (doubly-so since you don't have to press the release switch to change out of automatic mode on the FX-D).

The 139 has very nice mirror damping though