2275 no FM stereo Help

Hello Marantz fans Im working on a 2275 and can't get the Stereo light to work on FM braodcast I just need a little help on solving the issue or help in the right direction. Stereo light will work in Aux, phono.

I getting 6.0v on the collector of H317

I pulled H303 and was able to get 2.5v on pin 8 of chip HA1156

Reading through the forum the voltages in () are correct for stereo broadcast?

Also when I press the Muting switch sound is very low

Any suggestions?

Thanks

I would guess your FM stations don't come in strong enough to trigger the stereo light.

(1) When tuned to a station, what is your sig strength?

(2)...This will be hard to answer if you dont have an FM sig Gen.
When you tune a stereo station... Are you actually hearing stereo or is the sound mono?

(3) Pull the fm mute board off the back panel and look for a crack/broken traces

Hello thanks for responding.

The FM signal strength is strong.

No I don't have a signal generator at this time.

Yes i did pull the FM mute board and cleaned the pots.

After reading past post I guess the voltage on H317 is turning on H303


here is Catrafter post on the subject: I can't figure out why H317 is on


------------------------------------------------------------------------------------
This applies to the 2275, 2325 and probably the 2250B as well although some of the component designators are different.

FM Stereo MPX operation
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-ORed 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-ORed 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 noisey 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 OFF, 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)

Well poking around last night still try to fix the no stereo issue.

I replaced most of the transistors in the Fm muting circuit I also replaced the 2SK30y
n-channel FET H301 & H312 with mouser part J109

Fm still comes in strong but in Mono. Stereo decoder HA1156 pin 4 is now showing 8.60v almost the same as pin 5 I think I have a bad chip.

Stereo 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.

:thmbsp:

Tom

:thmbsp::yes:

Marantz 2275: Strong FM signal but almost no stereo

Vehto said:

Hello Marantz fans Im working on a 2275 and can't get the Stereo light to work on FM braodcast I just need a little help on solving the issue or help in the right direction. Stereo light will work in Aux, phono.

I getting 6.0v on the collector of H317

I pulled H303 and was able to get 2.5v on pin 8 of chip HA1156

Reading through the forum the voltages in () are correct for stereo broadcast?

Also when I press the Muting switch sound is very low

Any suggestions?

Thanks

Click to expand...

Hello dear all:
I am new here; to introduce me: my name is Joachim ...call me Joe... a retired biochemist, living in a little village of Upper Bavaria, Germany.
Seems I have a similar or perhaps the same proplem like Vehto did. Even when the FM signal strength of my 2275 is close to maximum, the stereo lamp almost never lights up - though it does always in the phone or AUX mode. I had the 2275 receiver recently checked by a prior Marantz, now Onkyo shop nearby, but apparently they only repaired/recapped the PM 800 circuit, not the PM 300 stereo decoder component. I thought about recapping the PM 300 unit myself, but failed to properly disconnect this component from the 2275 for soldering purposes because of so many connecting wires leading from or to other components.

I would therefore greatly appreciate any advice how best to handle the PM 300 component for recapping/underneath soldering purposes.

Many thanks in advance
Joachim

P.S.: rBuckner, so sorry for Sarge--have a lovely dog myself, Jochem, getting 10 this year, see my avatar.

You may want to read everything here and follow the flow chart on post #4

Its going to take getting your hands dirty, so to speak. Make sure to wrap the end of the probe in tape, or use mini clips, so you do not destroy anything. Shut it down during hook up. :yes:

Thanks for your kind comment Joe, and I hope your beautiful friend has great health for many years!

It could just need alignment, if it hasn't been done in the prior servicing. This is especially the discriminator which is one of two sections of a transformer (L201) on the IF board P200. It is the top section and the lower section is for the adjustment of the center tuning meter needle. That one can be adjusted with the antenna off and way off tune at either end of the dial (no signal). It takes the proper plastic hex alignment tool to turn the ferrite cores without breaking them. I don't know a European source for those type tools. It is covered on page 8 of the service manual, available in www.akdatabase.com.

It could also be the 19kHz pot (R311 on the P300 board) that's off but not as likely. make sure to mark the position of the slot on the pot before any adjustment of that pot. I'm betting you don't have the special alignment generator so just tune into a strong station and turn the pot a bit each way to see if the stereo light pops on. If not, return the pot to where it was - it was likely close enough.

Good luck and let us know how it goes. Scratch Jochem's ears for me!

It probably would have helped if i read the whole question before answering.

If you have to get in there, removing the amp will help. Just mark wires first and unsolder the pins with the wires left on. they come out , but its not a real joy.

Thanks a lot for your replies and suggestions. As one of the redoubtable "80% experts" equipped only with a normal digital multimeter and a soldering device, and most likely having to unsolder 20+ pins, I fear that I may cause more destruction than repair. Actually, I wanted to send my 2275 to the highly skilled AK member "ruesselschorf" (Helmut Thomas) here in Germany, but to my deep regret he passed away on February 23 this year, at the age of only 62, due to bone cancer. I will try it now with other well-known vintage Marantz experts over here, Armin and Lennart Kahn (http://www.good-old-hifi.de/).

Best wishes
Joe

Hello Joachim!

A hearty Welcome from the Black Forest to Bavaria. Thank you so much for the information about the cause of death of Helmut. I deeply appreciate this!

Christoph

I am sorry to hear of his passing:tears: Ak'ers names come and go and we never know why. He was a fine man.:yes:

HarmanKardon said:

Hello Joachim!

A hearty Welcome from the Black Forest to Bavaria. Thank you so much for the information about the cause of death of Helmut. I deeply appreciate this!

Christoph

Click to expand...

Hi Christoph
a hearty Welcome too from Upper Bavaria to the Black Forest - prior home of SABA German HiFi manufactury (not cuckoo clocks!). Actually, I own two vintage SABA 9260 receiver which still rank quite high here in the "local" community. Built in about 1980, they still have an almost unexcelled FM tuner sensitivity and resolution, together with a rather impressive amplifier.

But back to Helmut: I am glad that I myself had the opportunity to meet him personally. In about 1980, he had worked and lived for quite a while in the U.S. At that time he became so enthusiastic about Marantz HiFi, that - as he told me - when finally returning back home to Germany, he left behind all his clothing suitcases just to take with him a Marantz receiver without having to pay for extra airline charges...

I hope that such a personal anecdote is not beyond the scope of this forum. Persons like Helmut contributed and contribute so much to the preservation of vintage HiFi.

rBuckner said:

Thanks for your kind comment Joe, and I hope your beautiful friend has great health for many years!

(...) Good luck and let us know how it goes.

Click to expand...

Hello
I forgot to mention that I will ask the Kahn's to give me a report about the FM stereo problem and how they fixed it. I will then post an information about the result in this forum but this can take several months from now because they have a high workload at the moment.

Joachim / Joe

KutzlerTrans said:

It probably would have helped if i read the whole question before answering.

If you have to get in there, removing the amp will help. Just mark wires first and unsolder the pins with the wires left on. they come out , but its not a real joy.

Click to expand...

What if I alternately pinch off the wires from the pins, mark them and thereafter solder them to (1.3 mm) accessory shoes*) which are finally plugged onto the pins? This would allow to repeatedly remove and re-connect the P300 circuit board for all kind of soldering purposes. Or would there be problems with soldering the wire metal material?

*)Accessory shoes, in German "Steckschuhe", as,e.g., shown under http://www.elv.de/module/produktkatalog01/bilder_popup.aspx?art_id=38&bild_id=1171457

FM stereo back

2275Joe said:

What if I alternately pinch off the wires from the pins, mark them and thereafter solder them to (1.3 mm) accessory shoes*) which are finally plugged onto the pins? This would allow to repeatedly remove and re-connect the P300 circuit board for all kind of soldering purposes. Or would there be problems with soldering the wire metal material?

Wanted to describe a successfull attempt to restore FM stereo function (by replacing P300 transistors 2Sc828 with KSC1815Y according to the suggestion of Vehto), but I cannot submit a respective detailed reply to this forum. Any suggestions?

Joe / Joachim

Click to expand...

Sure, That would be a good idea!.:thmbsp:
It is too bad the factory didn't give us that option. Just double check your pin numbers/wire colors befor you snip them. If you cannot find the paper when you need it, we can help you figure out where they go.

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

"but I cannot submit a respective detailed reply to this forum. Any suggestions?"

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

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?