Hi Guys,
I'm a new member of this beautiful forum and I sure that someone can help me. 🙂
So, my old Marantz CD 84 not running, say ERROR, the motor on CDM-1 not starting. I have read all discussion on this forum of CD 74/84 issue I have checked all possible solutions but nothing....the motor in CDM-1 not running.
I have replaced all capacitors, 5 pcs 33uF on the laser PCB CDM-1.
I have checked the SERVO PCB, the Power Supply voltages are well, the motor circuit on the CDM-1 is good, in fact I have tried with 5V external power.
The two transistor (and both diode before) from SERVO PCB to motor circuit on CDM-1 are well.
The SERVO PCB gets -12V on the J204 connector pin 6 when the tray is closed and it's correct.
The motor is "kicked in" by the FCO signal coming from Q201 through C214 22uF/16V and this capacitor is ok.
I don't know but I have finisched the ideas and I don't know what i can check again!
Many thanks in advance.
Kind regards
franco
I'm a new member of this beautiful forum and I sure that someone can help me. 🙂
So, my old Marantz CD 84 not running, say ERROR, the motor on CDM-1 not starting. I have read all discussion on this forum of CD 74/84 issue I have checked all possible solutions but nothing....the motor in CDM-1 not running.
I have replaced all capacitors, 5 pcs 33uF on the laser PCB CDM-1.
I have checked the SERVO PCB, the Power Supply voltages are well, the motor circuit on the CDM-1 is good, in fact I have tried with 5V external power.
The two transistor (and both diode before) from SERVO PCB to motor circuit on CDM-1 are well.
The SERVO PCB gets -12V on the J204 connector pin 6 when the tray is closed and it's correct.
The motor is "kicked in" by the FCO signal coming from Q201 through C214 22uF/16V and this capacitor is ok.
I don't know but I have finisched the ideas and I don't know what i can check again!
Many thanks in advance.
Kind regards
franco
The spindle/platter motor will only run after the laser has found focus on the disc surface. As a generalisation the laser diode (LD) drive transistor can become faulty... its not common but not unheard of either.
In the first instance check the laser drive current (by carefully monitoring the voltage across the limiting resistor connected to the LD driver transistor. This will only be possible during the couple of seconds that the lens attempts to initially focus (when the lens moves up and down three times).
In the first instance check the laser drive current (by carefully monitoring the voltage across the limiting resistor connected to the LD driver transistor. This will only be possible during the couple of seconds that the lens attempts to initially focus (when the lens moves up and down three times).
Nothing really comes to mind I'm afraid.
Its a case of starting with the basics such as does the lens perform a focus search routine?, does the laser draw current?, and does the laser emit light.
Its a case of starting with the basics such as does the lens perform a focus search routine?, does the laser draw current?, and does the laser emit light.
Hi,
I have put in place some tests and the RX laser, indicated on the SM of CDM-1 like "monitor" it work, in fact with a directly flux of light the resistance it's change.
After that I have tried with TX laser but unfortunately I haven't emission 🙂-((
I have used a very low voltage external power supply with limited current but the TX laser absorb a some milliamperes but without emission.
I have no other way, I will hope to find a "surplus" CDM-1 for sale because the CD-84 and it had a "neutral" sound, aboveall a my old ears they was get used with this sound.......
Many thanks.
regards
franco
I have put in place some tests and the RX laser, indicated on the SM of CDM-1 like "monitor" it work, in fact with a directly flux of light the resistance it's change.
After that I have tried with TX laser but unfortunately I haven't emission 🙂-((
I have used a very low voltage external power supply with limited current but the TX laser absorb a some milliamperes but without emission.
I have no other way, I will hope to find a "surplus" CDM-1 for sale because the CD-84 and it had a "neutral" sound, aboveall a my old ears they was get used with this sound.......
Many thanks.
regards
franco
That doesn't sound good. You need around 50ma for the laser to operate but the current is extremely critical and varies from device to device. Also the laser diode is extremely sensitive to static discharge and can very easily be damaged.
I would not normally recommend testing a diode as you have done, you should always rely on the players laser drive circuitry and check by monitoring the current drawn and also checking for visible light. The light can be near invisible as it is mainly infra red. All you see is a very very dull red glimmer although looking at the laser through a digital camera will often show just how 'bright' it is.
I would not normally recommend testing a diode as you have done, you should always rely on the players laser drive circuitry and check by monitoring the current drawn and also checking for visible light. The light can be near invisible as it is mainly infra red. All you see is a very very dull red glimmer although looking at the laser through a digital camera will often show just how 'bright' it is.
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