2275 no FM stereo Help

FM stereo is back

"Replaced transistors 2Sc828 with KSC1815Y" Is this what you need help with Joe?

Yes, this appeared to be the solution. But nevertheless I don't succeed to describe all of my procedures applied and results in detail. Sorry,

Joe
 
FM stereo is back

If its something we can read, take a picture of it and use the "go advanced" option to add to a comment, OR click the paper clip at the top and browse your files to upload them. Does this help?

At least for a picture of the situation, you may perhaps have a look at the AK album;
picture 1 of 2 from Album Marantz 2275: Marantz 2275: MPX-Component PM 300. Hope you can get access.

Best wishes
Joe
 
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It sounds like you may have fixed it and want to explain it to us?? Is this correct?

Yes, that's correct. For those who might be interested, here’s a description about how I restored FM stereo function with the P300 unit (and making it easily accessible for all soldering purposes):
1. Snipping off all connecting wires from the pins, marking the wires by white adhesive tapes with the nos. of the respective pins written thereon.
2. Removing all residual wire coils from the pins
3. Tipping all pins with accessory soldering shoes (squeezing the shoes somewhat with a little gripper to get a solid contact with the pins)
4. Placing the disconnected P300 outside the 2275 gear, elongating all connecting wires with longer insulated copper wires and soldering them onto the accessory shoes. The P300 circuit could then be easily handled for all subsequent soldering and inspection purposes.
5. Inspecting the muting component didn’t reveal any defect, nor could the FM stereo signal be restored by changing the muting window
6. Replacing all electrolyte capacitors – except for the bipolar ones: couldn’t find any improvement
7. Replacing the IC HA1156R with a new IC, now placed on top of an IC socket: no improvement
8. Replacing all the transistors 2Sc828 with KSC1815Y, as described by Vehto before. With one of the transistors replaced--unfortunately didn’t make a note which one—FM stereo came back, both with the indicator lamp and acoustically.

Lacking most of the needed measuring equipment, I cannot explicitly state whether the stereo function recovery was due to the replacement of (one of) the transistors alone, or whether it was caused by a synergy with the prior replacement of other components.
Next I will replace the C306/C307/C309 bipolar capacitors by miniature MKS film capacitors, and thereafter put the p300 circuit back inside the 2275. With proper shortening of the wires leading to the accessory shoes, and all soldered joints insulated by heat shrink tubes. Hope everything continues functioning then, too...

Thank you so much for all your valuable advice
Joe / Joachim
 
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Hello Joe

I been out for over a month now, let me first say I'm very sorry to hear about Thomas Helmuts passing, he helped me with a few parts and advice on one of my 2270's. He will surely be missed!
Marantz tuner boards are still a challenge to me. I was only able to find my issue by replacing transistors re flowing solder joints and deoxit on the pots on the board.
Great info on your post!

Fred
 
Hi Joe,

I have the same issue you had.
Thanks for the procedure.
I was worried it was something like that. in a 4400 in my case.
I will proceed in the same way - will add pics of the procedure.
Not sure I will replace HA1156 and the xtors though.
In a low end 22xx - replacing the 2 big elcos was enough (10+ years ago) - they were leaking ==> power supply to HA1156 was too low and probably to all the other xtors too.

Thanks
Robin
 
Stereo:music: Finally

Bad solder joint, Adjusted muting window. Stereo kicked in ...

Stereo light seems to activate immediately just using an old pair of rabbit ears.

Replaced transistors 2Sc828 with KSC1815Y

Replaced bi polar caps C306, C307,&C309 with low ESR (0) Multilayer Ceramic Capacitors.

Replace all the caps with Nichicon muse or better.
Vehto:

you said: "Bad solder joint, Adjusted muting window. Stereo kicked in ..."

Q: do you remember exactly which solder joint, and/or on which board?

thanks
 
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