Hi Members & aficionados of Pioneer equipment, expecially FM lovers welcome to reply.
I am having nagging issue with my SX-680, the LED Stereo light is not coming on, I can listen to FM stations but it is for sire in Mono mode. When I press the Mono switch there is silence all across the FM band.
The Voltage of Pin 6 of IC PA1001A is stuck at 7.3 Volts and it does not vary once I am locked on a FM station.
The meter is showing signal strength.
TP1 Sawtooth is found but a little distorted.
Lissajou figure is also pretty good.
For your reference I am attaching the voltages I found on the two IC's.
I am suspecting a bad PA1001A.
Thanks
I am having nagging issue with my SX-680, the LED Stereo light is not coming on, I can listen to FM stations but it is for sire in Mono mode. When I press the Mono switch there is silence all across the FM band.
The Voltage of Pin 6 of IC PA1001A is stuck at 7.3 Volts and it does not vary once I am locked on a FM station.
The meter is showing signal strength.
TP1 Sawtooth is found but a little distorted.
Lissajou figure is also pretty good.
For your reference I am attaching the voltages I found on the two IC's.
I am suspecting a bad PA1001A.
Thanks
I have a sx-780 that has a great tuner
PA3001 is the detector if you are hearing FM it is working. PA1001 is the decoder. Replace all the small caps around it. If it is still not working the capture vco pot may be bad.
PA3001 is the detector if you are hearing FM it is working. PA1001 is the decoder. Replace all the small caps around it. If it is still not working the capture vco pot may be bad.
Tweaking the preset usually fixes most cases of 'no stereo' in my experience across many makes and models over the years. Give it a whizz end to end several times and then slowly turn it until lock is achieved. Now slowly turn each way and note the points lock is lost... and set midway between the two points.
(note the original position first so you can always reset it back if you still have issues)
First of all you need to have a good strong signal coming from the front end, assuming everything is aligned properly, the stereo decoder will only work if the signal is strong enough. If not it will force mono mode. Push switches and trimmer caps are notoriously famous for causing glitches. The other check is the 19 Khz pilot frequency. PA3001 is easy to find, PA1001 not really, both these IC's rarely go bad. The muting circuit is also a weak point in these receivers.
Hi
Check the capacitors C141 and C142 these electrolytes there were this problem. But you would need a stereo encoder for a quick and permanent repair. If you replace these 1uF capacitors do not do it with electrolytics.
Check the capacitors C141 and C142 these electrolytes there were this problem. But you would need a stereo encoder for a quick and permanent repair. If you replace these 1uF capacitors do not do it with electrolytics.