Alpine MRP-F240

mike49504 · 25th August 2011, 07:36 AM

Amp powers up and produces both - and + rail.. I get -15 volts on both pins 4 and 8 of all op-amps ..

Amp produces no sound any ideas where to check??

Perry Babin · 25th August 2011, 01:34 PM

I'm assuming that you've checked all switches and pots.

With the black probe on leg 1 of Q504 and the red probe alternately on each end of R516. What is the DC voltage on each end of R516?

mike49504 · 25th August 2011, 05:37 PM

On both ends i have -2.63 volts

Perry Babin · 25th August 2011, 08:24 PM

Drive a strong signal into the amp. Set the gain to the highest point and set the crossover off.

Which op-amps have signal on their output pins?

mike49504 · 25th August 2011, 09:22 PM

Non of the op-amps have signal on the output pins

Perry Babin · 25th August 2011, 09:37 PM

Do you have signal on the backs of the RCA jacks and where they solder to the board?

mike49504 · 26th August 2011, 12:40 AM

Yes

Perry Babin · 26th August 2011, 12:49 AM

At the top of the page, I assumed it was a typo but I may have been mistaken. Do you really have -15v on pin 8 of the op-amps?

If so, you need to find that fault first.

If it was a typo and you have +15 on pin 8, do you have signal on pin 5 of IC101 and IC102?

mike49504 · 26th August 2011, 12:55 AM

Not a typo its - 15 on both pins 4 and 8

Perry Babin · 26th August 2011, 01:21 AM

Did you attempt to repair the +15v regulator?

25th August 2011, 07:36 AM	#1
mike49504 diyAudio Member Join Date: Sep 2006	Alpine MRP-F240 Amp powers up and produces both - and + rail.. I get -15 volts on both pins 4 and 8 of all op-amps .. Amp produces no sound any ideas where to check??

25th August 2011, 01:34 PM	#2
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	I'm assuming that you've checked all switches and pots. With the black probe on leg 1 of Q504 and the red probe alternately on each end of R516. What is the DC voltage on each end of R516? __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

25th August 2011, 08:24 PM	#4
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	Drive a strong signal into the amp. Set the gain to the highest point and set the crossover off. Which op-amps have signal on their output pins? __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

25th August 2011, 09:37 PM	#6
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	Do you have signal on the backs of the RCA jacks and where they solder to the board? __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

26th August 2011, 12:49 AM	#8
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	At the top of the page, I assumed it was a typo but I may have been mistaken. Do you really have -15v on pin 8 of the op-amps? If so, you need to find that fault first. If it was a typo and you have +15 on pin 8, do you have signal on pin 5 of IC101 and IC102? __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links


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25th August 2011, 05:37 PM	#3
mike49504 diyAudio Member Join Date: Sep 2006	On both ends i have -2.63 volts

25th August 2011, 09:22 PM	#5
mike49504 diyAudio Member Join Date: Sep 2006	Non of the op-amps have signal on the output pins

26th August 2011, 12:40 AM	#7
mike49504 diyAudio Member Join Date: Sep 2006	Yes

26th August 2011, 12:55 AM	#9
mike49504 diyAudio Member Join Date: Sep 2006	Not a typo its - 15 on both pins 4 and 8

26th August 2011, 01:21 AM	#10
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	Did you attempt to repair the +15v regulator? __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

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