I would have said something more like 2.2 or 4.7 ohm, perhaps also a 'safety' type. That would be a common sort of value for a safety resistor in a supply line.
You need to do some measuring. 200 ohm will never fail on 5 volts, you can't pull enough current through it. Measure the volt on each side. You should see 5 volts on both.
If the cap was definitely faulty then that is the reason for failure of the resistor. If you are not sure then work down in value.
You need to do some measuring. 200 ohm will never fail on 5 volts, you can't pull enough current through it. Measure the volt on each side. You should see 5 volts on both.
If the cap was definitely faulty then that is the reason for failure of the resistor. If you are not sure then work down in value.
I think resistor value depends on that ic power consumption ,also keeping in mind , digital circuits allow about 5% deviation in power supply voltage ,so theoretically , 4.75-5.25v region . Typically there's should be no high drop , big capacitance 470uf tells us ,that resistor value can't be increased .As Mooly just said in #21 post , few ohms would be good choice . You can also put inductor there , less than 1Ohm DCR and maybe 100uH .Resistor was there to break power supply loop .
Good development guys, but a new problem.
I replaced the 200 Ohm resistor in question with a 4.7 Ohm and everything seems fine.
Reads discs instantly, output relay clicks but no sound. It's not in the headphones either.
Maybe I'll continue tomorrow.
I replaced the 200 Ohm resistor in question with a 4.7 Ohm and everything seems fine.
Reads discs instantly, output relay clicks but no sound. It's not in the headphones either.
Maybe I'll continue tomorrow.
that's good.Do check the voltage on each side of the resistor even though it seems OK. You don't want to be losing more than around 0.05 to 0.1 volts (at a guess) across it. It may need to go lower still.
Measure those voltages 🙂
Tomorrow sounds good if its still faulty.
When a cd is read with many errors , it gets muted, so laser power regulator circuit may be still in suspect ( capacitors ).
Don't over think it at this point. You've found a definite fault... work with that. Philips players are the ones with cap issues.
Check those voltages on the resistor first. You have to do that.
Check those voltages on the resistor first. You have to do that.
Hi guys.
The voltage across this resistor drops by 115.3 mV
Maybe I should replace it with a lower value.
The voltage across this resistor drops by 115.3 mV
Maybe I should replace it with a lower value.
Nothing lost in doing that. Try a 1 or 2.2 ohm.
If that doesn't work you will have to look at the RF from the pickup as a starting point and make sure the amplitude and general quality looks good.
Today there is no time left for the player, tomorrow is in question, but I'll be sure to share what happens.
I wish you a cheerful welcome on the new year!
I wish you a cheerful welcome on the new year!
I replaced the resistor with a 1.5 Ohm. The voltage drop is now 35 mV, but there is no sound ;//
Not mute button on remote control ... CD players have mute signal ,which mutes audio output ,if data read by laser contains too much errors ,crc mismatch and so .In other thread ,can't remember which one , was similar problem ,it was power supply ripple related , mute functioned incorrectly . Need to look to schematic . Look at mcu pins , they have signal names ,like data ,clk , and so , there's one named mute . IC3 pin 13 , RMUTE , i think this . Try to measure what voltage it has and where it goes .
There is a relay at the output called 'mute' although its drawn a little strangely.
See if you have audio (scope) anywhere on this path.
See if you have audio (scope) anywhere on this path.
There is a 5V on pin 13 "RMUTE" IC3, but there should also be 5V on pin 16 "MUTG", but there aren't any.
They must come/go to "signal processor IC1" pin 19 (this is the chip with the failed power supply)
Mooly, there is no audio signal at these opamp's
They must come/go to "signal processor IC1" pin 19 (this is the chip with the failed power supply)
Mooly, there is no audio signal at these opamp's
What show display of cd player while playing ? Does next/previous track change quick ,or its searching long time ? Does the seconds get displayed ? Can you fast forward a track ?
So , if there's no audio coming from dac , need to check with scope ,if dac is getting its data input, and if all supply voltages ant other things around are ok. Potentiometer in example - VR1 ,what would change ,if its open ? From schematic i see four data lines ,coming from ic10 digital filter .