I have a Galaxy Saturn that works great everywhere but FM. When you switch to FM it transmits but has no audio on receive, it get's a signal, just no sound comes out. Anybody got any ideas?
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Galay Saturn no audio on FM receive
- Thread starter spyedar7
- Start date
Switching to FM with a dummy load, or no antenna attached should produce a near-deafening rushing noise.
FM receive depends first on the mode selector to supply power to the FM-only receive detector chip IC2. The tuning adjustment L5 has to be set properly to work. Someone just twisting tuning slugs to see what happens won't see any effect from twisting L5 unless FM is selected. More than once we find that tuning slug randomly twisted way off from its peak position.
But that's the hit parade for FM receive failure. The FM chip uPC1028 almost never fails. Wouldn't start by blaming it.
73
FM receive depends first on the mode selector to supply power to the FM-only receive detector chip IC2. The tuning adjustment L5 has to be set properly to work. Someone just twisting tuning slugs to see what happens won't see any effect from twisting L5 unless FM is selected. More than once we find that tuning slug randomly twisted way off from its peak position.
But that's the hit parade for FM receive failure. The FM chip uPC1028 almost never fails. Wouldn't start by blaming it.
73
got another one for you Chris, the same radio, I bought a Fairchild MOSFET conversion kit installed it and have no RF output, and the lights dim when keyed, already replaced capacitor c703 as it was burnt up the side got any ideas, I'm a native live in Bullitt county
Just provided my best guess where to start in the private "conversation" section. Just where did the directions for this procedure come from? Are they available online anywhere? Might shed some light on where to find this fault.
Did have one other thought. TR51, the fat modulator transistor bolted to the rear of the audio chip is in danger of overload damage when the lights dim. When it fails, the transistor that drives it TR50 is also at risk of damage. TR51 usually fails as a dead short.
73
Did have one other thought. TR51, the fat modulator transistor bolted to the rear of the audio chip is in danger of overload damage when the lights dim. When it fails, the transistor that drives it TR50 is also at risk of damage. TR51 usually fails as a dead short.
73
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TR51 was upgraded according to instructions in the Saturn service manual it's no longer a 2SB754, it's an NTE-37.
As far as the source of the MOSFET conversion, it came from vintage schematics 4 you, and the guy there says this kit always works and is helping through this process as well wants to know what kind of voltages I'm seeing on the MOSFETS, but I can't get an accurate reading with the power supply circuits damaged so I'll get the power supply gone through and we will see what happens
As far as the source of the MOSFET conversion, it came from vintage schematics 4 you, and the guy there says this kit always works and is helping through this process as well wants to know what kind of voltages I'm seeing on the MOSFETS, but I can't get an accurate reading with the power supply circuits damaged so I'll get the power supply gone through and we will see what happens