Hello,
I'm an absolute novice when it comes to tuners and radio reception in general. However, I have a lot of experience with amplifiers and other electronics and I'm also talented at tinkering, so I'm looking forward to any tips on what to do...
About the problem:
I overhauled a KR-6600 and the only thing that still doesn't work is the tuner. There is only a noise and neither the tuning nor signal display moves when searching for stations.
IC HA1137w and HA1196 have been changed, transistors and that FET-thing in the tuner section checked (they are all ok), but errors are still there.
Now I noticed that if I touch pin 1 of the HA1137W with my finger or the tip of a screwdriver, the signal display moves and a distorted station can be heard, but only this one. When I turn the tuning dial, this one station remains distorted and nothing else happens.
What could that be, or where could the error lie? Once again, thank you very much for your effort and have a nice day everyone
I'm an absolute novice when it comes to tuners and radio reception in general. However, I have a lot of experience with amplifiers and other electronics and I'm also talented at tinkering, so I'm looking forward to any tips on what to do...
About the problem:
I overhauled a KR-6600 and the only thing that still doesn't work is the tuner. There is only a noise and neither the tuning nor signal display moves when searching for stations.
IC HA1137w and HA1196 have been changed, transistors and that FET-thing in the tuner section checked (they are all ok), but errors are still there.
Now I noticed that if I touch pin 1 of the HA1137W with my finger or the tip of a screwdriver, the signal display moves and a distorted station can be heard, but only this one. When I turn the tuning dial, this one station remains distorted and nothing else happens.
What could that be, or where could the error lie? Once again, thank you very much for your effort and have a nice day everyone
There are a few possibilities starting from the RF input through to the ha1137 quadrature detector.
It’s it a circuit failure or a tuning/ adjustment issue?
Need to determine where in the signal path the signal gets lost.
One can inject a 10.7MHz IF from a signal generator or another RF frontend to test the IF.
The RF front end testing can be done using a RF generator and monitor the IF output on a scope but that requires test gear.
Always test for proper power supply voltages and biasing as well.
It’s it a circuit failure or a tuning/ adjustment issue?
Need to determine where in the signal path the signal gets lost.
One can inject a 10.7MHz IF from a signal generator or another RF frontend to test the IF.
The RF front end testing can be done using a RF generator and monitor the IF output on a scope but that requires test gear.
Always test for proper power supply voltages and biasing as well.
Hello rsavas
Sorry for the late reply, but I'm very busy at the moment...
Thanks for the tips! Unfortunately, I don't have a signal generator that works in the MHz range or that would be suitable for this purpose. But since there was little input on my post, I'll try to read up on the topic and try to build a small FM transmitter.
Thanks anyway for your effort and have a nice day
Sorry for the late reply, but I'm very busy at the moment...
Thanks for the tips! Unfortunately, I don't have a signal generator that works in the MHz range or that would be suitable for this purpose. But since there was little input on my post, I'll try to read up on the topic and try to build a small FM transmitter.
Thanks anyway for your effort and have a nice day