Repair attempt of marantz 2240b with "no FM stereo" symptom.
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- Опубліковано 10 жов 2022
- Common symptom, but this one has a far bigger underlying problem.
Many are quick to jump to the HA1156w multiplex decoder IC because its readily available, or they replace the lamp because in some designs the lamp has to be good for the multiplex to start.
No so here. In many later marantz designs, the muting circuit is responsible for the audio output muting between stations, as well as controlling the command line to start or stop the multiplex. The tell is to turn the FM muting on. If the FM now goes silent, look to the muting circuit. If it does not, then we have to troubleshoot the multiplex.
In this scenario, the multiplex internal VCO is operating, taken from a test point, and the signal coming out of the detector is sufficient, and the signal strength at the meter is sufficient. The voltage at the control transistor that turns muting off and MPX on is missing.
lets try and find out why. - Наука та технологія
You darn right I enjoyed the journey. Understand it like you do, NO WAY. I'm going to watch it a few more times. Even if I did understand it setting up and arranging everything to test is near impossible. Not only that, one little slip and short and a cascade of damage occurs. It's great watching you go through it and to listen to your logic. Thanks for the video!
I've come across a few vintage tuners with "no FM reception / no FM stereo" issues and found they can be a lot harder to troubleshoot / more expensive to repair than anything else. FM failure seems to be a common fault. I hope your customer accepts the compromise you did with that Marantz receiver to restore FM stereo, based on the complexity and economics of the repair. 😎
Hi Jordan. Shango066 turned me on to your channel and been addicted ever since. I really enjoy how you deep dive when you can, like with this one. That’s what I like about Shango’s videos as well. You keep making them and I’ll keep watching them. To care bud!
I've had a number of vintage tuners over the years with the same symptoms. Some of them were well-regarded models. I opened them up and inspected them for bad solder joints and other stuff. In some of them, I'd already installed fresh capacitors (of the same type and capacitance as the originals.) They had performed very nicely until one day they just went silent. I did not know were to start with them. Currently I have a Pioneer that is dead on FM. I suspected it was chip death. But someone has suggested that it is the MUTING CIRCUIT. The same person has also suggested that if I "bridge" over some pins on one of the chips, I'll bypass the muting function (which I never use anyway) and regain FM stereo. I have yet to try this - a Pioneer TX-8800II - a Japanese model cuz I live in Japan. It's a slightly jazzed up version of the TX-7500II. I'm not good electronics so I could not properly follow your excellent presentation. But watch you work as if in real time was a treat.I hope I learning some stuff - THANKS!! (I'll subscribe)
Excellent job Jordan.Troubleshooting this these problems do not get any worse on these vintage Sansui Marantz and Pioneers unless you get into the RF amps. Well done on this dying trade
Watched every second of this, brilliant video jordan.
I just finished servicing this same model. Beautiful unit.
This was really interesting. You are so methodical and logical. Peace.
Definitely enjoyed the journey, thanks!
Excellent as usual! 🤙
Just a thought for next time, for now it is two months to late: that line is pulled down, but it is difficult to see which of the transistors is doing it, while there are about 5 that fit the bill. You could, according to the schematic, just pull down every base by shorting it to ground ( even the gate of the JFET ) to close a transistor and see which circuit does it.
You know I've had some tuners come across my bench that were stumpers. It is what it is. At least you were able to make it 'work'.
If the muting circuit functions normally but you have no stereo, try to align the 76kHz VCO (R611). If this restores stereo, replace H302, as leakage has shifted the VCO frequency. jHh
Very low voltage circuits are hard to diagnose sometimes. Textbook example here.
I bet H315 got cooked by the raised resistor that was touching it!
Conscientious attempt, can't win them all (for a reasonable budget). Too late and probably nothing but, at one point, you seemed to measure 6 Ohms between the bottom of C332 and ground / 0V so there may be an intermittent ground connection issue (or maybe not) which may explain some of the issues. Voltages in service manuals have to be taken with a whole salt cellar unless the manual states under what circumstances those voltages are present.
diagnostics troubleshooting is key troubleshooting aeverything testing related helps detrim the situation!!!!
Are you going to make anymore videos on the Sansui qrx 9001 receiver.?
That would be hours. Or many parts.
Where are you located? I just picked up a marantz 2385 that may need servicing. How can i get a hold of you? Thank you for your videos.
Located in san Diego county. Would have to be local delivery. Im not accepting ship-ins.
Repairaudio.com
Could you give me some help?? My Marantz 2220B works very well, I love the sound of it, but the STEREO lamp is very difficult to turn on on FM. On AUX-PHONO-TAPE it works perfectly, but on FM it is very difficult, although the FM station is picked up, the sound is clean, but the lamp turns on with great difficulty, stations above 100 are almost impossible to turn on the STEREO. And the few stations that the STEREO turned on were with a wire that goes outside the house, passing through the window, and another Technics receiver that I have picks up the signal 100% and the stereo turns on in all the stations with just a little bit of wire. Are there any adjustments I could make? I thank you in advance.
No easy fix or tweak, tuner needs to be analyzed with a generator and scope to see where the deficiency is.
Turn the muting switch on and see if thr sound mutes. If so, you've got an IF issue or front end issue causing lack of sensitivity.
@@JordanPier First of all, thank you for your attention. I did this test of turning on FM Muting. With the 99.9Mhz station well tuned and with the FM Stereo lamp on, when you press FM Muting the station remains tuned with the STEREO lamp on. But when trying to look for another station, I can't tune in any more, only if I go back to that 99.9Mhz. And without the Muting button turned on, I can get some more in this 90~102Mhz range with the Stereo lamp on, and I can get all the others with good tuning, clean sound, but without the Stereo lamp on.
@@rogeriozx1 sounds like the problem is specific to the multiplex circuit. Its not receiving enough of the 19lhz pilot signal to switch on. This could be due to lack of output from the fm detector circuit, a problem with the 19khz amplifier circuit in the multiplex, or the switching circuit that turns on the 38khz demodulation circuit which starts decoding.
@@JordanPier Once again, thank you very much for your attention. I'm going to look for a technician here in my city (Pompano Beach). I want to leave my Marantz 2220B perfect, 100% working.
Usually the discriminator coil has failed! It does not get the correct signal to switch into stereo.
I have Yamaha RX-450 stereo receiver with a similar problem it doesn't receives in stereo, auto tuning and meter for signal strength it doesn't work, I can't find a solution for this problem. Anybody help ?
🤔
So the muting is disabled, the owner is happy :-D.
Some faults feel like they are there to send you mad, nothing wants to play nicely.
I did have a grasp of stereo f.m decoding about 20 years back, but it all trickled out of one ear and was never seen again :-D.
Wafer switches are bitches. When all the components test fine, I always re-check rhe switches. D5 /100 doesnt cut it sometimes. Ca1010 was a full recap and speaker relays. Isses were the input switch. Intermintent isses....black oxide can reek havoc.
I have not listened to commercial radio for 20 years. Old school board with the ic chip. My self I would not spend any time or money on that thing. Like that old scope too.
Ever had a Marantz that had the Stereo light on at unit power on, and have it go out after about a minute? I have a 2330B doing this. Have no clue what's going on. Maybe something is warming up and turning the stereo MPX off? Thanks for this video. Kind of helps a little. LOL..
Most older marantz the stereo light comes in always in any other mode than the tuner. It was some sort of fancy gimmick to sell it. Only time it was off in this scenario was when you pressed the mono button
@@JordanPierThis one works that way.. Stereo light is on with Phono1 and 2 and Aux selected. When I power it up on FM I get stereo light for about a minute then the ground side of the bulb goes to 9VDC so it goes out. I don't have stereo separation when the stereo slight shuts off at the output of the Tuner board either as my scope shows. I tried the FM muting.. Nothing happened. Still have signal on the meters and still had audio in the speakers. Weird stuff.Hit the IC chip with some freeze spray and Voila.. Stereo light comes on. I'll be darned. LOL
@@brettbarnett9823 check VCO potentiometer. May have open spots. I'll usually set mid point where there's stereo separation
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totally enjoyed the video, now go to the garage ,get the garbage can and dump it on the workbench. A MAN CA NOT HAVE ENOUGH CRAP ON THE WORKBENCH OBVIOUSLY!
Hi Jordan... Just sent you and Email... Great Video..Look for the subject Repair Marantz 120 Tuner. Regards: Mark
Huh. In the end it was the owner's fault that you could not fix it. Wow.
If you can, you should do something about your microphone. The volume is all over the place.
Please mándame foto delos transistores de chapas del JVc 300
I need a more specific model number. Have you tried locating a service manual yet?
I've got an Accuphase T101 that has the no stereo symtom and I'm tearing my hair out over it and to make it more interesting my T1000 stereo generator has gone haywire.
That's why they call them dogs.
diaper furry friends are going to be able to make a difference in their lives
That's for sure...LOL
Say what?, blue gloved devil!
Oh !! 😮 that’s excrement !
So, where is Stereo repair?? 😂
if you dont have an antenna you have no stereo
I'm disappointed, I liked the content and your approach but wished you continued the repair. Customer or not. Sometimes you get a difficult job and others are easy. The best repairs are the ones that others can't fix.
True, but I also do this for a living so if I dont get paid and expend the time on technical heroics when I could earn - there's no way I could continue to pay bills
Tell us how you really feel @tom sheridan 🙄
@@JordanPier I JUST DID. I BET YOU COULD HAVE FIXED IT IF YOU REALLY TRIED! 🤮
@@JESUSCHRYSLER5512 sure, if I poured hours into it. Gotta make a living, and can't do it tunnel visioned on one machine.
@@JordanPier I IMAGINE YOU VOMITING IN THE RECEIVER THAT YOU DID NOT WANT TO FIX