Help with Xtant x603 - Page 4

shawnk · 10th February 2010, 04:53 AM

I did check each driver individually before I replaced/reinstalled them. I'm pretty confident that I placed them in the correct locations as I had written down where each one belongs on the board. Plus I have another x603 here that I can use for reference.

Is it common for the protection not to kick in? Under what conditions will the protection circuit not work?

Perry Babin · 10th February 2010, 01:22 PM

It sometimes takes a significant amount of current to trigger the over-current protection and a 10 amp fuse will blow before the protection circuit can trip.

Pull Q48 and Q50. Does it still draw excessive current?

With those out of the circuit, what is the DC voltage measured directly across the speaker terminals for this channel?

shawnk · 10th February 2010, 04:08 PM

Hmmm. Ok. with Q48 and Q50 removed, the amp fires up, but I have 5v at the output terminal. Yikes!

Perry Babin · 10th February 2010, 06:17 PM

That may indicate that you have a leaking output transistor.

If you measure the resistance from the gate of one of the N-channel outputs to the gate of one of the P-channel outputs in that channel, what do you read?

If you measure the resistance from one of the N-channel output gates to the gates of all of the other N-channel outputs in that channel, What do you read?

Do the same for the P-channel outputs in that channel. What do you read?

No power applied for these tests.

shawnk · 11th February 2010, 01:23 AM

Ok.
Resistance from N-channel to P-channel= ~45k
Resistance from N-channel to N-channel= ~45k
Resistance from P-channel to P-channel= ~75k

shawnk · 11th February 2010, 01:24 AM

All measurements were gate to gate.

Perry Babin · 11th February 2010, 01:42 AM

Are you sure that wasn't ohms instead of K ohms?

shawnk · 11th February 2010, 02:12 AM

Sorry. I went back and measured again.

It seems that a couple of the N-channel fets are off compared to the other four.

One N-channel fet reads ~95k between it and the others
One N-channel reads ~6mega ohms
The other four will read just 45 ohms not 45k

P-channel to P-channel is also 45 ohms on all gates no matter the combination(not sure how I got 75.. I might not have had enough pressure on the leads)

from the four N-channels that read 45 ohms at the gates, I get 45kilo ohms from it's gate to any P-channel gate

Perry Babin · 11th February 2010, 02:22 AM

In front of the outputs, there is a row of resistors. Measure the resistance directly across all of them that are marked 220 or 470. Did you replace any of these resistors previously?

shawnk · 11th February 2010, 02:52 AM

OK
R75 is up over 6mega ohms

All others measure 22 & 47 ohms respectively

Can an open gate resistor cause heavy current draw? Just trying to learn here.

10th February 2010, 01:22 PM	#32
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	It sometimes takes a significant amount of current to trigger the over-current protection and a 10 amp fuse will blow before the protection circuit can trip. Pull Q48 and Q50. Does it still draw excessive current? With those out of the circuit, what is the DC voltage measured directly across the speaker terminals for this channel? __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

10th February 2010, 06:17 PM	#34
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	That may indicate that you have a leaking output transistor. If you measure the resistance from the gate of one of the N-channel outputs to the gate of one of the P-channel outputs in that channel, what do you read? If you measure the resistance from one of the N-channel output gates to the gates of all of the other N-channel outputs in that channel, What do you read? Do the same for the P-channel outputs in that channel. What do you read? No power applied for these tests. __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

11th February 2010, 01:42 AM	#37
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	Are you sure that wasn't ohms instead of K ohms? __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

11th February 2010, 02:22 AM	#39
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	In front of the outputs, there is a row of resistors. Measure the resistance directly across all of them that are marked 220 or 470. Did you replace any of these resistors previously? __________________ 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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10th February 2010, 04:53 AM	#31
shawnk diyAudio Member Join Date: Dec 2009	I did check each driver individually before I replaced/reinstalled them. I'm pretty confident that I placed them in the correct locations as I had written down where each one belongs on the board. Plus I have another x603 here that I can use for reference. Is it common for the protection not to kick in? Under what conditions will the protection circuit not work?

10th February 2010, 04:08 PM	#33
shawnk diyAudio Member Join Date: Dec 2009	Hmmm. Ok. with Q48 and Q50 removed, the amp fires up, but I have 5v at the output terminal. Yikes!

11th February 2010, 01:23 AM	#35
shawnk diyAudio Member Join Date: Dec 2009	Ok. Resistance from N-channel to P-channel= ~45k Resistance from N-channel to N-channel= ~45k Resistance from P-channel to P-channel= ~75k

11th February 2010, 01:24 AM	#36
shawnk diyAudio Member Join Date: Dec 2009	All measurements were gate to gate.

11th February 2010, 02:12 AM	#38
shawnk diyAudio Member Join Date: Dec 2009	Sorry. I went back and measured again. It seems that a couple of the N-channel fets are off compared to the other four. One N-channel fet reads ~95k between it and the others One N-channel reads ~6mega ohms The other four will read just 45 ohms not 45k P-channel to P-channel is also 45 ohms on all gates no matter the combination(not sure how I got 75.. I might not have had enough pressure on the leads) from the four N-channels that read 45 ohms at the gates, I get 45kilo ohms from it's gate to any P-channel gate

11th February 2010, 02:52 AM	#40
shawnk diyAudio Member Join Date: Dec 2009	OK R75 is up over 6mega ohms All others measure 22 & 47 ohms respectively Can an open gate resistor cause heavy current draw? Just trying to learn here.

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