no stereo sound Marantz 2216

[El moncho]

Hi everyone

Please your advice and help to fix my first Marantz 2216 which I am with a restoration project

I bought a Marantz 2216 which did not have the capacitors in the amplification stage (P700) and the transistors of the right channel were not the original ones, after installing the new components I turned on the equipment and I noticed that when I turned it on it had a slight hum in both channels that lasts a few seconds, then it works fine but the problem that the equipment has is that it does not have stereo audio and the light does not turn on, when reading different recommendations from other members of AudioKarma is that I decided to check the power source (P800) and I measured the value of the capacitors, the results are as follows:


I also measured the voltages delivered by the power source (P800) and the values are as follows


Is it possible that this difference in values in the capacitors and voltage is the cause of not having stereo sound?

Please your help to understand what may be happening with the team, in advance I appreciate all your advice and guidance.

 

[AE Bob]

None of those measurements are outside the norm. You can easily expect a 10% tolerance in those type of readings. You will need to do some logical troubleshooting.

When you say "the problem that the equipment has is that it does not have stereo audio and the light does not turn on" are you stating that the unit is not in stereo in any mode, or that the stereo FM is not working?

 

[El moncho]

Thanks Bob for your answer, I have not done audio tests with a deck or a turntable, during the weekend I will connect the equipment and I will comment on the results

 

[Steven Tate]

An easy piece of info to get is whether the stereo light comes on when you switch to phono or aux mode. It should. If not, you either have a bad bulb or wiring/switch problem. If the bulb works in those modes, but not FM, then the problem is in the tuner section - probably in the MPX circuitry.

 

[El moncho]

Thanks Steven Tate for your answer,

Today I have tested the inputs with turntable and Deck and both work well, they have stereo audio, also check the lamp and it is good, so the problem must be in the Tuner board (P100), check the service manual and the H301 It is the IC HA1156 which is FM Stereo Demodulator so I measured the voltages on each pin, the results are as follows:


The voltage that enters the board (J122) is 32.8V, manual indicates that 33.7V must enter, when reviewing the circuit I have thought that it could be the resistors R311 and R312 that are bad due to the voltage difference on the pin 1, I have also thought that the C304 or C305 capacitors may be bad since pin 13 the voltage is correct but pin 12 has less voltage, I await your comments since I suspect that the problem may be in this section.

 

[Steven Tate]

I would be looking for the lost volt+ at J811. Everything at H801 is low. Why? If you find your volt, then see what you get at pin 1 on H301. If still low. Why? I have no idea if the missing voltage is the problem. But it seems like it would be worthwhile to track it down before looking elsewhere.

 

[AE Bob]

I would suspect that the voltage differences are not great enough to cause the issue.

I am assuming that you have audio from the FM tuner, and that it is just not in stereo.

I would note the position of R302, then adjust it slowly from end to end while a strong stereo station is tuned in, while watching the stereo indicator lamp. If the lamp comes on at some point, note the area of rotation where it is on, and center the pot in that area. If the PLL (phase locked loop) oscillator free run frequency is too far off, it will not be able to pull in and lock, and you will not get stereo FM. If "rocking" the pot does not correct the issue, then put it back where it originally was.

 

[El moncho]

I leave greeting all the people who participate in this forum and thanking their advice, after several weeks doing different tests I share an update of the results obtained:

Review the soldering on the power source board (P800) since I noticed that when I reinstalled the capacitors I had not soldered properly, after this I measured the voltage again and got the following values in IC H301

Since pins 6, 8, 10, 12 and 14 had different voltages, check the schematic and take out the capacitors C304, C305, C306 to check them and I found that the capacitors C304 and C306 were giving very high values so I swapped them for generic capacitors ( some recommendation of which capacitor to place), also change the C321 capacitor because it is swollen, after the change the values were adjusted to what is indicated in the schematic, remaining as follows


As pins 6 and 8 continue with higher voltages again, I checked the schematic and decided to check the transistor H302 which has the following values


I replaced it with a new transistor and the values were the same so I am thinking that the problem is in the IC H301, what do you think?

As additional information, I can tell you that when you are tuning in to different stations in some, when moving the dial slowly in some stations, the audio rises in level, the stereo light turns on and stereo audio is heard but it is only for fractions of a second, this does on different transmitters but it is always for fractions of a second and cannot maintain stereo audio.

As additional information I found other problems in the equipment, I do not know if I should open a new post, I realize that when I am listening to a station and pressing the Tape Monitor key, the station's audio is heard very slowly but with a buzzing noise ground connection and when touching the chassis of the equipment the hum decreases or disappears, this hum is also present when I listen to audio from a turntable the same thing happens, I touch the chassis and the hum disappears, last night I was checking the equipment and I noticed that the tone amplifier card (PE01) was removed, the nuts were loose, I checked it and it has no sign of having been intervened.

I apologize if the post is very long but I made a summary of everything I have done so far, I only ask for your understanding and your advice to move forward.

 

[Steven Tate]

I noticed that pin 6 on the schematic lists two voltages, one in parentheses. 0 and 10.6V. One is represents when signal is high enough to process a signal, and one represents with low signal. I'm not sure which is which, but the fact yours is 10.8 makes me think that value represents low signal. Maybe check pin 6 voltage with tuner in between stations, and again on the strongest station you can get. I found this thread that talked about a similar problem. Give it a good read.
https://audiokarma.org/forums/index.php?threads/fighting-with-a-2275s-fm-mpx.896448/#post-13348240

 

[catrafter]

I noticed that pin 6 on the schematic lists two voltages, one in parentheses. 0 and 10.6V. One is represents when signal is high enough to process a signal, and one represents with low signal. I'm not sure which is which,

Generally speaking, in the IF area, the number in parentheses is with a strong station (signal generator) tuned in. In the MPX decoder area, the number in parentheses is with a strong Stereo station (signal generator tuned in.

Tom

 

[El moncho]

I noticed that pin 6 on the schematic lists two voltages, one in parentheses. 0 and 10.6V. One is represents when signal is high enough to process a signal, and one represents with low signal. I'm not sure which is which, but the fact yours is 10.8 makes me think that value represents low signal. Maybe check pin 6 voltage with tuner in between stations, and again on the strongest station you can get. I found this thread that talked about a similar problem. Give it a good read.
https://audiokarma.org/forums/index.php?threads/fighting-with-a-2275s-fm-mpx.896448/#post-13348240

Thanks Steve, I understand that the problem of the 2275 equipment was solved by changing the capacitor C244 of the P200 FM board? Check the schematic and it is similar to the 2216 so I will check the transistors of that stage to confirm if they are with the correct voltages

 

[El moncho]

Greetings everyone, I have resumed this project after several weeks without time, I have seen the advice that they have given me so I checked the voltage of all the transistors, most of the transistors give voltages according to the electrical scheme, however there are some transistors that have different values which are the following:


In the cases that I indicate two voltages like the H110 transistor, the base delivers a variable voltage, it is never fixed unlike the collector that the voltage is fixed at 13.22 V, I think these are the transistors that are bad and the ones that cause not If you have Stereo sound, please give your opinions and advice to make the decision to buy the transistors and replace them.