re post 18/7/2005 Thank you all. I would like to do this test but I need to check about correct procedure: would it be proper to solder a 3.9 zener diode with the - end to the tuner's AGC pin and the + end to the tuner's ground. I understand the idea is to clamp the voltage to 3.9; is this right? I will wait for confirmation. Al.
Re HDTV Teac cm-687 is this what I should try?
Jul 20, 2005
3 Replies
That would be the proper way. To make sure, check that the AGC line actually contains a resistor so as not to short anything with the zener diode. Then connect the zener directly between the tuner pin (cathode) and the ground (anode).
Met vriendelijke groet,
Maarten Bakker.
Thanks Maarten I now must say that the AGC pin from the tuner is connected directly to the pin of the I/C; no resistor is connected in series between the 2 pins. However there is a couple of resistors off this line therefore in parrallel. Is this still okai to do the test? Thanks for your input. Al
There is a risk of blowing up the IC. Disconnect the tuner pin and use a variable power supply directly to the AGC pin of the tuner. Or use a 9V battery with a 10k variable resistor.
Met vriendelijke groet,
Maarten Bakker.
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