Alpine MRP-M350

tn350 · 13th March 2011, 08:37 PM

Hey guys, so I have an Alpine MRP-M350 amp that has just recently decided to stop working. The blue led light still comes on when the amp is on, and I have a multimeter and tested the voltage input to the amp and it is 14V. But I am getting absolutely nothing on the output terminals. All fuses are good and there is no evidence of the amp being fried (see pic below).

I took the amp to a repair shop and they said that the amp wasn't drawing any current. Does anyone know what could be wrong with it? I'd hate to trash this thing, its a great amp!

Perry Babin · 14th March 2011, 04:30 AM

What is the DC voltage on the legs of Q601, Q603, Q604 and Q606? They should all be about the same. If they are, you only need to post the voltage for one of them. Place the black meter probe on the amplifier's ground terminal. Place the red meter probe on the point where you need to measure the voltage.

tn350 · 14th March 2011, 06:39 PM

The DC voltage on Q601, 603, 604, and 606 is 14V if i measure the middle leg of each. The other legs are 0VDC.

Perry Babin · 14th March 2011, 08:59 PM

Do you see a UPC494, TL494 on the board?

tn350 · 14th March 2011, 09:25 PM

I see a NEC C494GS...is this an equivalent?

Perry Babin · 14th March 2011, 09:53 PM

That's it. Post the DC voltage on all 16 pins. Place the black meter probe on the amplifier's ground terminal. Place the red meter probe on the point where you need to measure the voltage.

IC#
Pin 1:
Pin 2:
Pin 3:
Pin 4:
Pin 5:
Pin 6:
Pin 7:
Pin 8:
Pin 9:
Pin 10:
Pin 11:
Pin 12:
Pin 13:
Pin 14:
Pin 15:
Pin 16:

tn350 · 14th March 2011, 10:15 PM

Ok here are the DC voltages at the upc494:

Pin 1: 0.0264 V
Pin 2: 4.51 V
Pin 3: 3.64 V
Pin 4: 0 V
Pin 5: 0 V
Pin 6: 0 V
Pin 7: 0 V
Pin 8: 0.55V
Pin 9: 0 V
Pin 10: 0 V
Pin 11: 0.45 V
Pin 12: 0.45 V
Pin 13: 0 V
Pin 14: 0 V
Pin 15: 0 V
Pin 16: 0 V

Perry Babin · 15th March 2011, 03:42 AM

What's the DC voltage on the three legs of Q664?

tn350 · 15th March 2011, 05:18 AM

The Q664 is positioned in a way that I cant get the probe on any of the legs to get a reading. But there is a small metallic "dot" next to Q664 that I placed the probe on and I'm reading 14 VDC.

Perry Babin · 15th March 2011, 11:00 AM

You'll have to pull the board out of the heatsink.

13th March 2011, 08:37 PM	#1
tn350 diyAudio Member Join Date: Mar 2011 Location: Chicago	Alpine MRP-M350 Hey guys, so I have an Alpine MRP-M350 amp that has just recently decided to stop working. The blue led light still comes on when the amp is on, and I have a multimeter and tested the voltage input to the amp and it is 14V. But I am getting absolutely nothing on the output terminals. All fuses are good and there is no evidence of the amp being fried (see pic below). I took the amp to a repair shop and they said that the amp wasn't drawing any current. Does anyone know what could be wrong with it? I'd hate to trash this thing, its a great amp!

14th March 2011, 04:30 AM	#2
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	What is the DC voltage on the legs of Q601, Q603, Q604 and Q606? They should all be about the same. If they are, you only need to post the voltage for one of them. Place the black meter probe on the amplifier's ground terminal. Place the red meter probe on the point where you need to measure the voltage. __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

14th March 2011, 08:59 PM	#4
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	Do you see a UPC494, TL494 on the board? __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

15th March 2011, 03:42 AM	#8
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	What's the DC voltage on the three legs of Q664? __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

15th March 2011, 11:00 AM	#10
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	You'll have to pull the board out of the heatsink. __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links


	Please consider donating to help us continue to serve you. Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving

14th March 2011, 06:39 PM	#3
tn350 diyAudio Member Join Date: Mar 2011 Location: Chicago	The DC voltage on Q601, 603, 604, and 606 is 14V if i measure the middle leg of each. The other legs are 0VDC.

14th March 2011, 09:25 PM	#5
tn350 diyAudio Member Join Date: Mar 2011 Location: Chicago	I see a NEC C494GS...is this an equivalent?

14th March 2011, 10:15 PM	#7
tn350 diyAudio Member Join Date: Mar 2011 Location: Chicago	Ok here are the DC voltages at the upc494: Pin 1: 0.0264 V Pin 2: 4.51 V Pin 3: 3.64 V Pin 4: 0 V Pin 5: 0 V Pin 6: 0 V Pin 7: 0 V Pin 8: 0.55V Pin 9: 0 V Pin 10: 0 V Pin 11: 0.45 V Pin 12: 0.45 V Pin 13: 0 V Pin 14: 0 V Pin 15: 0 V Pin 16: 0 V

15th March 2011, 05:18 AM	#9
tn350 diyAudio Member Join Date: Mar 2011 Location: Chicago	The Q664 is positioned in a way that I cant get the probe on any of the legs to get a reading. But there is a small metallic "dot" next to Q664 that I placed the probe on and I'm reading 14 VDC.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
alpine mrp-m1000	mike49504	Car Audio	45	16th October 2011 10:03 PM
alpine mrp-f250	bdgf2004	Car Audio	12	2nd September 2011 04:26 AM
Alpine MRP-M350	RiLoWa	Car Audio	37	3rd December 2010 08:23 PM
Service maanual for MRP-M350	DigiSoft	Car Audio	0	17th March 2010 08:26 PM
Alpine MRP-M1000	argonrepublic	Car Audio	2	11th August 2009 02:28 PM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read