Really good can Cosina CT-1 type camera's metering circuit uses dual comparator IRC2403, metering element is a complex type CdS photoresistor . Semi- adjustable resistance RW3, RW4 setting window level ( "3 " for the upper level , "5 " for the lower level ) , the function potentiometer RASA, RF and RT were introduced sensitivity, aperture and shutter speed. Semi- adjustable resistance RW1, RW2 is used for non-linear compensation photoresistor . Light-emitting diodes H1, ​​H2 and H3 role with Haiou DF-1ETM cameras . S1 is the shutter button metering switch , S2 for the B gate power switch. In addition , similar to the circuit shown in Figure 2 Japan Nikon FM, Chinon CM-4, YashICa Fx such as cameras used in metering circuit diagram overhaul for reference.

 

Second, the repair method

 

General maintenance procedures Seagull DF-1ETM and really good kind can Cosina CT-1 SLR camera metering circuit is: First check the battery power supply is normal , switches S1 and S2 contact is good ; Second, check the light-emitting diode H1, H2 and H3 good or bad, they are usually integrated package of special plastic pieces are wearing parts ; then multimeter to check whether each function of the potentiometer resistance change ( manually adjustable aperture F, shutter speed and sensitivity T ASA) with the exposure parameters change , without change may be bad or lead and carbon brushes wear layer ; Finally, specific symptoms, focus on examination of integrated circuits and working conditions outside the biasing element is normal. Common symptoms and the cause of the fault as shown in the Schedule , you can quickly find the condemnation under the table to the point of failure , and then take appropriate measures to troubleshooting.