Marantz SR3001 Full dead

[hemant_2222]

Hello everyone,

Hope you are doing well.

This is my first attempt to repair Marantz and the receiver I am looking at is SR3001. It is in fully dead condition.

Here is what has been done/checked so far.

Earlier when I received this unit, I found the primary of the standby transformer was broken. I replaced the transformer with another which now give 5volts at the output of the regulator IC94.

The reset IC96 has the below voltages;
Pin1 --OUT--4.95v
Pin2 --INPUT--7.9v
Pin3 --GND--0v

Voltages present on connector CN83 are as follows;
+5D=0v
CEFL=0v
SEL=5.02
RCOUT =0V
SEL+=0V
ST_LED=4.42V
RSFL=0V
VOL-=0V
VOL+=0V
OSDDA=0V
OSDCK=0V
RSTFL=0V
KEY=0V
KEY1=0V
KEY2=0V

and CN80 are;

HP_ON= 0V
HP_DET=4.3V
ST_BY=0V
HEAT=4.87V
SUR_ON=0V
FLR_ON=0V
P_AMP_FAIL=0.85V
P_DOWN=5V
P_LINE_FAIL=0.85V
GND=0V
GND=0V
+5VL=5V
+5VL=5V
AVSS=0V
SB_ON=0V

I have attached the schematic for this unit for reference.

Any help on this would be appreciated. Let me know if any more measurements are needed.

Thank you,
Hemant

[hemant_2222]

Re: Marantz SR3001 Full dead

Hello,

Can anybody put their suggestions, as I am unable to proceed. At least can someone check what are the voltages required by the micro at least to say it is alive.

Thanks,
Hemant

[hemant_2222]

Re: Marantz SR3001 Full dead

Hello all,

Here are some updates that may help in getting further direction in troubleshooting.

When I keep the multimeter on 200 Ohms with one pin (-ve) grounded and other at pin number ST_BY=0V on CN80, the power relay clicks and there is a display as well, but in a bit skewed manner and when I takeout the +ve pin of multimeter, the relay switches off.

Another, when the same multimeter arrangement is touched on ST_LED=4.42V of CN83, the standby LED is lit up but then no other buttons work on the front panel.

Any suggestion from above will be helpful

Thank you

[stj]

Re: Marantz SR3001 Full dead

the reset i.c. should pulse it's output low for a second at power-up
worth checking
infact go straight to the computer and check for clock and reset

[hemant_2222]

Re: Marantz SR3001 Full dead

the reset i.c. should pulse it's output low for a second at power-up
worth checking
infact go straight to the computer and check for clock and reset

================
The reset IC does gives a -ve pulse for a very short interval. Just like a blip and is maintained at near 5v.

And the reset pin of the micro is held high: near 5v as soon as the power button is switched on. As per the pin diagram it must be held LOW, right..if you could please confirm this.

I am not sure, how to measure the clock though i have an oscilloscope. I don't know the settings to see if the crystal is okay or not.

Any suggestions on the above.

Regards,
Hemant.

[stj]

Re: Marantz SR3001 Full dead

the reset pin should be low for a blip, then high.
(usually - sometimes inverted)

if your multimeter has frequency then you can check crystals if they arent too fast.
most meters can do 4MHz atleast.