Howdy.. got a Marantz 2275 im trying to diagnose. Recapped the entire unit. When I got it FM was dead (not even static) recap gave the power supply the required 13V DC at J806, J104, J211, and J304. now I have FM but its all white noise (static) across the entire dial... where do I go from here ? The meters do not respond under FM but work perfectly under AM. Thanks in advance.
FM tuner gurus !... HELP ! LOL Marantz 2275.
- Thread starter xalara76
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Understand but the first thread was in regards to the channel loss. Perhaps a new one will be for tuning issues. Thanks
catrafter
Marantz Specialist
Quoting myself, what have I devolved to?
An easy way to check if the FM is good at least to the output of the discriminator is to set the receiver for FM operation and tune in a known good station (use the meters if they work).
Now use an RCA cable to connect the Quadradial output on the rear panel to the left tape monitor (1) input jack. You should get sound in the left channel when you press the tape monitor (1) push button.
Tom
An easy way to check if the FM is good at least to the output of the discriminator is to set the receiver for FM operation and tune in a known good station (use the meters if they work).
Now use an RCA cable to connect the Quadradial output on the rear panel to the left tape monitor (1) input jack. You should get sound in the left channel when you press the tape monitor (1) push button.
Tom
FaceTime hey Tom, thanks for your input. I did try that with the tape one monitor into the Quadra dial out with and 3.5mm on the other And plugged into my phone and I got the phones music playing through FM function on the receiver. Am I supposed to use just a single cable RCA and not one with a 3 1/2 mm on the end?. I did get sound through that one left channel as stated what does this mean?
catrafter
Marantz Specialist
I didn't indicate that you should use your phone, I'm not sure what your 'test' indicates.
Please try this again,
Set the receiver for FM operation and tune in a known good station (use the meters if they work).
Now use an RCA cable to connect the Quadradial output on the rear panel to the left tape monitor (1) input jack. You should get sound in the left channel when you press the tape monitor (1) push button.
If you get sound in the left channel then:
This applies to the 2275, 2325 and probably the 2250B as well although some of the component designators are different.
Note: An 'ON' NPN transistor has a base voltage about 0.6V more positive than the emitter. This will cause the collector to become very near the emitter voltage.
Wire-anded: the junction of two or more components where either one can pull that point to or near ground potential.
FM Stereo MPX operation:
Intermediate Frequency (IF) signal strength is monitored by H308. If signal strength is above muting level, H308 is ON, H309 is OFF.
If there is excessive noise, then H311 is ON which is wire-anded to H309 keeping H301 (FET) OFF.
If the discriminator is outputting DC due to the tuning being off station, either H314 or H315 is ON which are wire-anded to H309 as well. This also turns H303 ON grounding Pin 8 of the decoder forcing MONO operation.
If the station is properly tuned, not noisy and the signal strength is high enough,
H308 is ON, SS OK
H309 is OFF, SS OK
H311 is OFF, Noise is OK
H314 is OFF Tuning centered
H315 is OFF Tuning centered
H317 is ON, SS, Noise and center tuning OK then:
H301 is ON allowing audio and MPX signal to pass into the decoder.
H303 is OFF If SS sufficient for Stereo operation and MONO button is not pressed
H302 is OFF VCO runs (AM not selected)
Tom
Please try this again,
Set the receiver for FM operation and tune in a known good station (use the meters if they work).
Now use an RCA cable to connect the Quadradial output on the rear panel to the left tape monitor (1) input jack. You should get sound in the left channel when you press the tape monitor (1) push button.
If you get sound in the left channel then:
This applies to the 2275, 2325 and probably the 2250B as well although some of the component designators are different.
Note: An 'ON' NPN transistor has a base voltage about 0.6V more positive than the emitter. This will cause the collector to become very near the emitter voltage.
Wire-anded: the junction of two or more components where either one can pull that point to or near ground potential.
FM Stereo MPX operation:
Intermediate Frequency (IF) signal strength is monitored by H308. If signal strength is above muting level, H308 is ON, H309 is OFF.
If there is excessive noise, then H311 is ON which is wire-anded to H309 keeping H301 (FET) OFF.
If the discriminator is outputting DC due to the tuning being off station, either H314 or H315 is ON which are wire-anded to H309 as well. This also turns H303 ON grounding Pin 8 of the decoder forcing MONO operation.
If the station is properly tuned, not noisy and the signal strength is high enough,
H308 is ON, SS OK
H309 is OFF, SS OK
H311 is OFF, Noise is OK
H314 is OFF Tuning centered
H315 is OFF Tuning centered
H317 is ON, SS, Noise and center tuning OK then:
H301 is ON allowing audio and MPX signal to pass into the decoder.
H303 is OFF If SS sufficient for Stereo operation and MONO button is not pressed
H302 is OFF VCO runs (AM not selected)
Tom
Steven Tate
CEO Flat Forehead Soc.
I think I’m going to print this and laminate it.
