Hi, there's someone here in the forum that can help me with my turer marantz?
The scan of the frequency go in step mode only.automatic search doesn't work.
Any advice to check?
The scan of the frequency go in step mode only.automatic search doesn't work.
Any advice to check?
It is possible to adjust based on the schematic but it requires you to understand how it works to begin with.
You need a DVM and a non-conductive screw driver to adjust L201.
Let the unit warm up for 30 minutes or so with the cover on. Remove all the screws for the cover prior to this and locate L201 quadrature transformer, J201 and J202 test points. J201 and J202 is where you will connect the DVM.
Tune to a strong signal manually with an antenna. Note the DC voltage across J201 & J202. Ignore the polarity, all you care about is the absolute value. Carefully adjust L201 until it is very close to 0V.
Done!
Let the unit warm up for 30 minutes or so with the cover on. Remove all the screws for the cover prior to this and locate L201 quadrature transformer, J201 and J202 test points. J201 and J202 is where you will connect the DVM.
Tune to a strong signal manually with an antenna. Note the DC voltage across J201 & J202. Ignore the polarity, all you care about is the absolute value. Carefully adjust L201 until it is very close to 0V.
Done!
There aren’t that many adjustments for the ST-520. The signal strength has also an effect on the automatic search, you need to connect a proper antenna that will peg the signal strength.
The muting switch position might also affect automatic search. Note R220 trimmer position with a marker, this is the muting level adjustment. Try both directions.
Make sure you set the correct tuning step 200kHz vs 50kHz for FM depending on your location.
Good luck!
The muting switch position might also affect automatic search. Note R220 trimmer position with a marker, this is the muting level adjustment. Try both directions.
Make sure you set the correct tuning step 200kHz vs 50kHz for FM depending on your location.
Good luck!
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I will try again,...you have the complete service manual with the adjustments procedure? Thanks
S.
S.
I don’t have the service manual. I’m also looking at the same schematic as you and that is where I base my suggestions.
I do detailed work on FM stereo tuners, a schematic is sufficient for me and if there isn’t one I just reverse-engineer it.
Auto-tuning doesn’t always work on FM tuners, new and old. If it worked before and not anymore, you can spend more time figuring it out if not, move on.
You already zeroed out the quadrature coil, that is major step. The rest requires more test equipment.
I do detailed work on FM stereo tuners, a schematic is sufficient for me and if there isn’t one I just reverse-engineer it.
Auto-tuning doesn’t always work on FM tuners, new and old. If it worked before and not anymore, you can spend more time figuring it out if not, move on.
You already zeroed out the quadrature coil, that is major step. The rest requires more test equipment.