I think Q205 (LM339) pin4 uses the FCO signal to generate a kick start to the motor. On my system pin4 measures 6.95V, pin5 6V, pin2 69mV, FCO at 4.6V. When I use multimeter to measure pin4 voltage, sometime I can see motor spins briefly, I guess the measurement cause some interference and generates some MCES pulse.
I will try the 5V MCES idea, oshifs, in your working system, what is the vpp voltage for the MCES signal?
I will try the 5V MCES idea, oshifs, in your working system, what is the vpp voltage for the MCES signal?
MCES is 0V at idle, then alternates between 0 and +5V but only after the motor started rotating. Note that I had to short pin 3-4 on PT10 connector JT06 with an U-shaped wire (black ribbon cable coming from the back RCA panel PW10). This is because the REMOCON signal at pin 3 should be 0, and after I removed the RCA panel, this went up to 5V. If a transistor is faulty on the RCA board, it may produce the same symptom - motor does not start. I would check also the AUTO READ TRAY IN END SWITCH. There are some small black PCB fuses on the power supply board, did you check all voltages?
Yes, I also shorted REMOCON to ground and unplug the 5 pin remote cable completely, but that has no help. I disconnected MCES from decoder board and directly supply 5V to MCES on servo board, the motor does spin at the max speed. From scope I can also observe the initial kick MCES signal generated by Q205 pin2 but it only last a few milliseconds. Once the FCO become high, pin2 goes to 0V. Oshifis, is it possible you check Q205 pin2 on your system to see how long the kick pluse last?
I also observed the SAA7030 runs very hot on the decoder board, and the -2.4V reference voltage is at -2.9V. Is it normal for SAA7030 to run hot?
Really appreciate your help.
I also observed the SAA7030 runs very hot on the decoder board, and the -2.4V reference voltage is at -2.9V. Is it normal for SAA7030 to run hot?
Really appreciate your help.
Sorry for the delay. I couldn't measure at Q205 but I think pin 4 on SAA7020 is the same and it is more accessible
The signal is 0V when no button is pushed. When I push the Play button, the signal goes to +5V and there is a signal with high duty cycle (zero level is narrow, high level is wider). Then as the motor spins up, it reverses, zero will be wider, high is narrow. Then in 1 or 2 seconds, the duty cycle becomes around 50%.
When I turn on the player with a CD in, or when I insert a CD and the tray is closed, the same thing happens (I think this is why the Tray end signal is called Auto-Read)
I don't know how hot is the SAA7030 because I bypassed it (converted the player to NOS). The -2.4V has +/-20% tolerance, so -2.9V is within limits.
The signal is 0V when no button is pushed. When I push the Play button, the signal goes to +5V and there is a signal with high duty cycle (zero level is narrow, high level is wider). Then as the motor spins up, it reverses, zero will be wider, high is narrow. Then in 1 or 2 seconds, the duty cycle becomes around 50%.When I turn on the player with a CD in, or when I insert a CD and the tray is closed, the same thing happens (I think this is why the Tray end signal is called Auto-Read)
I don't know how hot is the SAA7030 because I bypassed it (converted the player to NOS). The -2.4V has +/-20% tolerance, so -2.9V is within limits.
Sinning Problem solved
Little bit late, but maybe I can help someone with the same problem.
In the power supply are some black fuseble resistors (6x)
One of them was gone.
No reading of TOC:
My CD84 did the same. If the drive can't focus the motor will not spin. Very important to focus is the hight of the turntable. I did start at the lowest position. At this point the tabel can't spin at all. The adjust the table as long as the tabe can spin. By adjusting the table every time a little bit higher as long as the drive will read TOC at the end.
But start with the changing of the caps of the turntable. 5x 33 uF
Little bit late, but maybe I can help someone with the same problem.
In the power supply are some black fuseble resistors (6x)
One of them was gone.
No reading of TOC:
My CD84 did the same. If the drive can't focus the motor will not spin. Very important to focus is the hight of the turntable. I did start at the lowest position. At this point the tabel can't spin at all. The adjust the table as long as the tabe can spin. By adjusting the table every time a little bit higher as long as the drive will read TOC at the end.
But start with the changing of the caps of the turntable. 5x 33 uF
Hi Icsaszar, nice to meet you
I have a problem with a marantz cd84.
CD player runs normally except for one, no sound on line out or headphones
I've checked all 3 JRC 4560 DD preamp ICs, everything looks normal
If you have experience with this cd player, please help me. Thank you
Goodbye
Rasymar
I have a problem with a marantz cd84.
CD player runs normally except for one, no sound on line out or headphones
I've checked all 3 JRC 4560 DD preamp ICs, everything looks normal
If you have experience with this cd player, please help me. Thank you
Goodbye
Rasymar
Hello, guys
I have a problem with a marantz cd84.
CD player runs normally except for one, no sound on line out or headphones
I've checked all 3 JRC 4560 DD preamp ICs, everything looks normal
If you have experience with this cd player, please help me. Thank you
Goodbye
Rasymar
Transistor Q536, not Q532 which controls relay L510 is in normal condition, not muting position. Only in the schematic in the service manual, the JRC 4560DD preamp IC on pin 7 or pin 1 on other ICs has a voltage of 3.6 volts. On measurement, it only puts out 0.4 volts.
Can anyone explain about this problem?
I have a problem with a marantz cd84.
CD player runs normally except for one, no sound on line out or headphones
I've checked all 3 JRC 4560 DD preamp ICs, everything looks normal
If you have experience with this cd player, please help me. Thank you
Goodbye
Rasymar
Transistor Q536, not Q532 which controls relay L510 is in normal condition, not muting position. Only in the schematic in the service manual, the JRC 4560DD preamp IC on pin 7 or pin 1 on other ICs has a voltage of 3.6 volts. On measurement, it only puts out 0.4 volts.
Can anyone explain about this problem?
Indeed Q536. If you have 2mA idle current coming from the DAC chips (TDA1540P) that would drop 3.6V on R592 and on R612 (1.8k). But it is unlikely that both DAC chips have faulty and sends nearly zero current.
I'd rather suspect the DAC chips do not get proper digital signals on ther input. If all the power lines -6V, -17V, +5V (2 different), +12V, -12V you checked on J503 connector and around the SAA7030, then next step is to check the digital signals coming out of the SAA7030 with an oscilloscope. Also check the SAA7000 digital outputs, especially the LAT signal on pin 11.
I'd rather suspect the DAC chips do not get proper digital signals on ther input. If all the power lines -6V, -17V, +5V (2 different), +12V, -12V you checked on J503 connector and around the SAA7030, then next step is to check the digital signals coming out of the SAA7030 with an oscilloscope. Also check the SAA7000 digital outputs, especially the LAT signal on pin 11.
Problem with the Marantz CD84 cd player
The voltage on the J503 connector is all normal, sir.
Does that mean you think there is damage to the IC SAA7030 or the IC SAA7000?
Sorry I don't have an oscilloscope to check the digital signal on the SAA7030 output.
Is there another way to determine that the SAA7030 or SAA7000 is faulty?
Please solve. Thank you
The voltage on the J503 connector is all normal, sir.
Does that mean you think there is damage to the IC SAA7030 or the IC SAA7000?
Sorry I don't have an oscilloscope to check the digital signal on the SAA7030 output.
Is there another way to determine that the SAA7030 or SAA7000 is faulty?
Please solve. Thank you
Without a 'scope you're pretty much knackered, unless there are enough voltage annotations on the circ diag to confirm the 'normal' voltages (but manufacturers often get these misplaced or just plain wrong anyway.
You need a 'scope.
This is indeed helpful. Thank you PAM! I am dealing with my Magnavox FD3040, identical to CD74. Same problem with no spinning, solved by adjusting motor spindle height. However it rarely recognize TOC, only very occasionally. Once it gets TOC, it reads fine. I'll try changing the caps next.