Alpine mrd-m300

elec972 · 9th March 2010, 02:01 PM

Hello
i'm looking for schematics Alpine MRD-M300
power supply probleme
Thanks

brandes.cm · 9th March 2010, 04:25 PM

What is the problem with the supply?

PacParts sells the schematic along with other sites. They sell a complete CD of all the models for Alpine. I didn't want to pay price though.

elec972 · 9th March 2010, 07:56 PM

I work with MRD-M301 schematics not exactly the same
No pulse pin 9 and 10 from UPC494GS , i have 0v pin 4 , if this pin is 5V psu works fine
but without good schematics , it's hard to find .
Thanks

brandes.cm · 9th March 2010, 08:48 PM

Is the 5V ref on pins 13 and 14?

elec972 · 9th March 2010, 08:53 PM

yes 5V on pins 13 ,14 and 15

brandes.cm · 10th March 2010, 03:09 AM

Can you post the mrd-m301 schematic or send it my way?
brandes.cm@gmail.com

elec972 · 10th March 2010, 11:28 AM

Ok
i send schematics

brandes.cm · 10th March 2010, 12:13 PM

Q561 is the control transistor for pin 4 of the 494. What does the signal do on the base leg? That is driven directly from u501 pin 19. You can short that transistor and the amp should turn on. Leave it on for a few seconds and feel for warm parts.

You may have another issue causing that pin to stay high.

elec972 · 10th March 2010, 01:03 PM

I have not Q561 on MRD-M300 but Q563, Q562 not exactly the same schematics as MRD-M301
that's why i'm looking for schematics!!
Thanks

brandes.cm · 10th March 2010, 01:48 PM

See attached pic, in red box. Off the upper left hand corner of the 494 chip.

9th March 2010, 02:01 PM	#1
elec972 diyAudio Member Join Date: Dec 2005 Location: martinique FWI	Alpine mrd-m300 Hello i'm looking for schematics Alpine MRD-M300 power supply probleme Thanks

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9th March 2010, 04:25 PM	#2
brandes.cm diyAudio Member Join Date: Sep 2009 Location: Wisconsin	What is the problem with the supply? PacParts sells the schematic along with other sites. They sell a complete CD of all the models for Alpine. I didn't want to pay price though.

9th March 2010, 07:56 PM	#3
elec972 diyAudio Member Join Date: Dec 2005 Location: martinique FWI	I work with MRD-M301 schematics not exactly the same No pulse pin 9 and 10 from UPC494GS , i have 0v pin 4 , if this pin is 5V psu works fine but without good schematics , it's hard to find . Thanks

9th March 2010, 08:48 PM	#4
brandes.cm diyAudio Member Join Date: Sep 2009 Location: Wisconsin	Is the 5V ref on pins 13 and 14?

9th March 2010, 08:53 PM	#5
elec972 diyAudio Member Join Date: Dec 2005 Location: martinique FWI	yes 5V on pins 13 ,14 and 15

10th March 2010, 03:09 AM	#6
brandes.cm diyAudio Member Join Date: Sep 2009 Location: Wisconsin	Can you post the mrd-m301 schematic or send it my way? brandes.cm@gmail.com

10th March 2010, 11:28 AM	#7
elec972 diyAudio Member Join Date: Dec 2005 Location: martinique FWI	Ok i send schematics

10th March 2010, 12:13 PM	#8
brandes.cm diyAudio Member Join Date: Sep 2009 Location: Wisconsin	Q561 is the control transistor for pin 4 of the 494. What does the signal do on the base leg? That is driven directly from u501 pin 19. You can short that transistor and the amp should turn on. Leave it on for a few seconds and feel for warm parts. You may have another issue causing that pin to stay high.

10th March 2010, 01:03 PM	#9
elec972 diyAudio Member Join Date: Dec 2005 Location: martinique FWI	I have not Q561 on MRD-M300 but Q563, Q562 not exactly the same schematics as MRD-M301 that's why i'm looking for schematics!! Thanks

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