marantz 2225 stereo light
- Thread starter rc11
- Start date
mcsew2k
Active Member
Are you still getting FM audio when center tuned and zero signal strength? Is it stereo? This may be beyond my meager knowledge. Can anyone else help?
petehall347
the brandy coffee man
is the antenna adequate ?
With no signal (a quiet area of the dial) the tuning needle should be at zero. When you tune to near maximum signal the needle should be at zero. As you tune off the signal slightly to either side, the needle should move left and right. If those things aren't happening, there might be something wrong with the tuner, or it might be out of alignment.
mcsew2k
Active Member
So what you are saying, as you approach the peak signal of the station the signal meter will continue to rise and the tuning meter will approach the center. Broadcast audio will still be coming through (mono or stereo?). As the tuning meter needle nears the center the signal meter drops (suddenly?) to zero and you loose all audio (static or silence?). As you continue tuning the signal returns and you regain audio. The tuning meter is now deflected to the opposite direction. At no time does the stereo light come on in this process. Acts the same with the mono switch in.
Does this happen on all stations?
Is AM working?
I am looking at the schematic trying to think it through, but I am learning as I go. Someone here must have seen this before?
mcsew2k
Active Member
markallen
Luddite Tendencies
Title here describes my situation, so going to pick up this thread and hope someone can help solve this vexing problem on my 2225. I do fairly well with most aspects of vintage receiver repair - EXCEPT FM.
I've read as many threads as I can on this topic, but can't seem to get a stereo FM light. Here's what I know:
1. No Stereo light on FM. Works fine on Aux, Phono, Tape. BTW, the original was burned out, so I replaced it with an LED with a resistor in line.
2. Flushed tuning capacitor shaft contacts and function selector switch with non-residue contact cleaner twice. Flushed mono switch also.
3. Though the unit seems to play clearly in mono, the signal strength meter never gets more than halfway from rest position to the first mark. Yes, there's a good antenna.
4, The signal strength meter runs up past 4.5 on a good AM signal, so I know it works.
5. The center tuning works, but hangs a bit to the left on no signal. Doesn't seem to swing equally in both directions (I've seen this on these classic Marantz receivers before).
6. FM muting on shuts down all sound across the dial.
7. Checked all voltages on HA-1156. All are very close to the diagram specs in service manual.
8. I've flushed and then tweaked R304. Nothing. Adjusting it doesn't seem to affect any voltages on HA-1156.
9. Have checked voltages on all transistors on the 300 board, and all seem to be pretty close to voltages in the service manual diagram. Nothing really odd to report.
Some comments lead me to believe the FM discriminator is the problem. I don't know what that is or what components to diagnose. But it seems logical (signal strength, FM muting) that the problem has to do with not getting a good signal through to the FM stereo circuit. The only equipment I have is a DMM.
Not sure where to go from here. Suggestions?
I've read as many threads as I can on this topic, but can't seem to get a stereo FM light. Here's what I know:
1. No Stereo light on FM. Works fine on Aux, Phono, Tape. BTW, the original was burned out, so I replaced it with an LED with a resistor in line.
2. Flushed tuning capacitor shaft contacts and function selector switch with non-residue contact cleaner twice. Flushed mono switch also.
3. Though the unit seems to play clearly in mono, the signal strength meter never gets more than halfway from rest position to the first mark. Yes, there's a good antenna.
4, The signal strength meter runs up past 4.5 on a good AM signal, so I know it works.
5. The center tuning works, but hangs a bit to the left on no signal. Doesn't seem to swing equally in both directions (I've seen this on these classic Marantz receivers before).
6. FM muting on shuts down all sound across the dial.
7. Checked all voltages on HA-1156. All are very close to the diagram specs in service manual.
8. I've flushed and then tweaked R304. Nothing. Adjusting it doesn't seem to affect any voltages on HA-1156.
9. Have checked voltages on all transistors on the 300 board, and all seem to be pretty close to voltages in the service manual diagram. Nothing really odd to report.
Some comments lead me to believe the FM discriminator is the problem. I don't know what that is or what components to diagnose. But it seems logical (signal strength, FM muting) that the problem has to do with not getting a good signal through to the FM stereo circuit. The only equipment I have is a DMM.
Not sure where to go from here. Suggestions?
catrafter
Marantz Specialist
Hi Mark,
Since the signal strength meter is low, I suspect there might be a problem in either the antenna leads, the tuner, the IF amp or the discriminator.
I don't have the manual on this one, as soon as I find a readable schematic I may have some better info for you.
Tom
Since the signal strength meter is low, I suspect there might be a problem in either the antenna leads, the tuner, the IF amp or the discriminator.
I don't have the manual on this one, as soon as I find a readable schematic I may have some better info for you.
Tom
MBuras
Restoration is an Addiction
The 2225 and 2230B are very nearly identical. If you have a schematic for the 2230B it might be better quality.
markallen
Luddite Tendencies
Nope, not on this model.
The (+) side of the meter goes through the selector and appears to connect to the P200 board at J211 and/or the P100 board at J104. Having said that, I'm not sure I'm reading the path through the selector switch correctly. The 2230B schematics may be a bit clearer, but that doesn't help MY limited knowledge!
