Power Amplifier repair

Thread Starter

runtek

Joined Nov 3, 2019
3
How difficult is to repair a Power amplifier in stereo receiver?
The receiver model is shown in the link below. It's not an actual item I want to repair, but it same model as mine, so can be useful for information purposes:
Stereo Receiver undercover

How reliable is a board-level repair of such type of PCB board?
 
Last edited:

MrChips

Joined Oct 2, 2009
25,928
Welcome to AAC!
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Your country
Make and model number
Symptoms
History of unit, before and during the failure, such as, original owner vs bought as-is at booth sale etc., smoked when turned on?
 

bertus

Joined Apr 5, 2008
21,860
Hello,

Looking at the first picture the unit is a Denon DRA-F109.
I have not yet found a schematic for it.

There is stated the amplifier part is 65 + 65 Watts.
Looking at the PCB, it is likely a class D amplifier.

Bertus
 

Thread Starter

runtek

Joined Nov 3, 2019
3
Hi,
I don't have this receiver yet, I'm considering to buy it for repair. From the info I have, the receiver LED flashing red, I assume the output transistors are faulty, and possibly, surrounding components, too.
manual & schematic
 
Last edited:

bertus

Joined Apr 5, 2008
21,860
Hello,

As I thought, the output is a Class D.
See the block diagram:

DRAF109 block diagram.png
Here is a triubleshooting from the manual that shows the flashing led.
The speed of flashing seems to show different errors:

DRAF109 trouble shooting.png

Bertus
 

Thread Starter

runtek

Joined Nov 3, 2019
3
Based on Troubleshooting guide, it can be Power Supply fault and many other fault, depending on power LED flashing intervals.
(differs from other Denon model RCD-M40, where red blinking means amplifier circuit malfunction).
In case of Renesas M3030RFGPFP MCU chip failure, replacing it can be a pain, as it have 100-pins..
I should to know Led flashing frequecny, is it 1/4 sec or 1/2 sec
 
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