Wrapping up a restoration on a 2270 for a customer. I’m getting no power to the AM or FM section of the unit. No meter movement or sound at all under those two inputs. Everything else works fine. Looking over P800 and suspect this being the issue. Getting only 6.7 volts of power on J801. Should be 13.5 I believe. What to check next ? All caps are new on P800. Transistors are original.
Marantz 2270 no power to FM / AM.
- Thread starter xalara76
- Start date
Register to hide this ad
Got that sorted, moved some wires out of the way and replaced H803. I now have sound coming from AM & FM.. Am works perfectly so thats good. FM I get great signal but only strong signal strength on ONE station across the entire display. Tuning meter moves just fine. I have an antenna attached and cleaned muting and multipath switch. Stereo light confirmed working in Aux, Tape & phono.
Any input on boosting the signal strength sensitivity ?
Timmer pot R561 on P550 maybe?
I'd check the dc voltages at all stages of the IF board/section to see if any were far off. In general, the bases in the stages are around 3-5 volts and the emitters off by about 0.6 volts and collectors around 10 volts. One of the later and possibly last stages is a bit different if this is the IF section of a 2270 that I'm remembering. (!!)
A full alignment should be attempted if the IF voltages look good. I once got a unit in for refurb that had a dead FM, just hiss. I hung a wire from my RF spectrum analyzer in by the local oscillator area and found that it tuned off the dial, even including the 10.7MHz offset! Yup, somebody monkeyed with it as I was able to adjust it back in without changing any parts in the front end.
A full alignment should be attempted if the IF voltages look good. I once got a unit in for refurb that had a dead FM, just hiss. I hung a wire from my RF spectrum analyzer in by the local oscillator area and found that it tuned off the dial, even including the 10.7MHz offset! Yup, somebody monkeyed with it as I was able to adjust it back in without changing any parts in the front end.
Still digging into this. Another member pointed to replacing the P300 board, but I have no idea how that would effect the AM section as well. Again, I get NO AM , NO FM.. no hiss, no static, nothing ! Meters do deflect from what I remember. I have a hunch this is power supply related.
AK577
Active Member
Does the tuner section get its power from the transformer or the power supply board. Only 6.7 volts when it should be 13+ seems like the issue? I had lower voltage to a few boards on my Marantz, I replaced all the capacitors and even transistors on the power supply board. Now it’s all perfect.
Either one of the boards that uses 13.5V is drawing too much current bringing down the voltage on J801 to 6.7V, or there is a problem with H803.
- Measure the voltage of EBC voltages of H803 (with respect to Gnd) and compare against the schematic
- If still low, remove the wire on J801 and see if the voltage comes up to about 13.5V, if not then there is a power supply problem
- If J801 comes up, then comes the tedious task of lifting each wire that carries voltage to the individual tuner boards and see which one is pulling it down