Maker Pro
Maker Pro

Amp keeps going into protection mode

Rick79

Nov 26, 2014
283
Joined
Nov 26, 2014
Messages
283
Harman kardon Signature Series 2.1

All channels working. I let it run for a few couple of hours and everything seems to be ok, but when i put the volume up to hear it louder, it Keeps going into protection mode. Regardless if i use only one speaker, a large speaker, a small speaker, or a different pre-amp.
I was wondering if anyone recognizes this issue and knows what i should replace, test or look for on the board.
 

Attachments

  • IMG_20160515_210409.jpg
    IMG_20160515_210409.jpg
    191.1 KB · Views: 196
  • IMG_20160515_210441.jpg
    IMG_20160515_210441.jpg
    227.5 KB · Views: 207
  • IMG_20160515_210523.jpg
    IMG_20160515_210523.jpg
    220.5 KB · Views: 162
  • IMG_20160515_210608.jpg
    IMG_20160515_210608.jpg
    223.5 KB · Views: 169
  • IMG_20160515_210907.jpg
    IMG_20160515_210907.jpg
    220.3 KB · Views: 165

dorke

Jun 20, 2015
2,342
Joined
Jun 20, 2015
Messages
2,342
Any flashing LED?
Any code on the display?
 

Rick79

Nov 26, 2014
283
Joined
Nov 26, 2014
Messages
283
Any flashing LED?
Any code on the display?

There's no display. There's just the word "Signature" illuminated in Blue when its powered on. When it goes into protection mode, the Signature word turns off and a Red LED flashes for a few seconds before it resets and turns back on again.
 

Attachments

  • IMG_20160515_202157.jpg
    IMG_20160515_202157.jpg
    268.2 KB · Views: 160

dorke

Jun 20, 2015
2,342
Joined
Jun 20, 2015
Messages
2,342
If you crank the volume up with the speakers dis-connected what do you get?
 

dorke

Jun 20, 2015
2,342
Joined
Jun 20, 2015
Messages
2,342
With the Amp disconnected from power test resistance of each speaker output between (+) and ( -) [red and black].
Should be high on all output channels.
 

Rick79

Nov 26, 2014
283
Joined
Nov 26, 2014
Messages
283
With the Amp disconnected from power test resistance of each speaker output between (+) and ( -) [red and black].
Should be high on all output channels.

How do i do that with this meter?
 

Attachments

  • IMG_20160516_033200.jpg
    IMG_20160516_033200.jpg
    210.9 KB · Views: 127

dorke

Jun 20, 2015
2,342
Joined
Jun 20, 2015
Messages
2,342
For diode testing the bottom one.
For ohm 2k Range the other.

You can do both for each output,
remember,amp disconnected from power.

ohm-test.png
 

dorke

Jun 20, 2015
2,342
Joined
Jun 20, 2015
Messages
2,342
Next is checking for DC voltage on each output.
It should be very low (less than 100mV,ideally zero ).
You do that with the amp powered on.

First do it with volume at minimum and note the results.
Then(If the above didn't find anything abnormal) crank up the volume to the point the amp goes into "Protect" and lower the volume a bit,so it will not go into protect .
test the DCV on each output.
 

Rick79

Nov 26, 2014
283
Joined
Nov 26, 2014
Messages
283
Next is checking for DC voltage on each output.
It should be very low (less than 100mV,ideally zero ).
You do that with the amp powered on.

First do it with volume at minimum and note the results.
Then(If the above didn't find anything abnormal) crank up the volume to the point the amp goes into "Protect" and lower the volume a bit,so it will not go into protect .
test the DCV on each output.

Do i set the meter to the 200m Range?
On that range it showed -19.5 before going in protection mode, and as it is in protection mode, it shows -93.5
 

dorke

Jun 20, 2015
2,342
Joined
Jun 20, 2015
Messages
2,342
Yes DC 200mV range.
Is this what you get on all channels?
 

dorke

Jun 20, 2015
2,342
Joined
Jun 20, 2015
Messages
2,342
You have 5 channels each with it's own PA like below:
Check that each stage has the ±55VDC across the big blue filtering caps.
It may be easier to check(carefully!) the voltages on the grey 6.8K /2W resistors next to the caps.

If all voltages are present(a total of 10).
Do this:
Disconnect the power.
Mark the 3 pins connectors (those with 2 black and single blue wires) and take them all(5) out.
Try putting the amp in "protect" as before.
First, with all connectors out.
Gradually add a connector for each channel(each time disconnecting the power before you do) till you find the faulty one.

2-1 amp 55v.PNG
 

Rick79

Nov 26, 2014
283
Joined
Nov 26, 2014
Messages
283
You have 5 channels each with it's own PA like below:
Check that each stage has the ±55VDC across the big blue filtering caps.
It may be easier to check(carefully!) the voltages on the grey 6.8K /2W resistors next to the caps.

If all voltages are present(a total of 10).
Do this:
Disconnect the power.
Mark the 3 pins connectors (those with 2 black and single blue wires) and take them all(5) out.
Try putting the amp in "protect" as before.
First, with all connectors out.
Gradually add a connector for each channel(each time disconnecting the power before you do) till you find the faulty one.

View attachment 26861

Ok, with all the connectors off, i cranked the volume up and its fine, it doesn't go into protect mode. But i just tried connecting each one at a time like you said and they all make the amp go in to protect mode.
 

dorke

Jun 20, 2015
2,342
Joined
Jun 20, 2015
Messages
2,342
Is the ±55v present on each channel?
What do you read ?
 

Rick79

Nov 26, 2014
283
Joined
Nov 26, 2014
Messages
283
Is the ±55v present on each channel?
What do you read ?

Sorry, i forgot how to do this. When you say "across" that means positive probe on one location, and the negative probe on the other location you described on the resistors?

Or can you please circle the locations on the photo where im supposed to put the positive and negative probes on the resistors?
 

Attachments

  • IMG_20160515_210523.jpg
    IMG_20160515_210523.jpg
    220.5 KB · Views: 132
Top