rockford 501s one bad channel

stoke · 12th January 2011, 05:21 PM

this amp came with one not working channel but after replaced all the transistor of the bad channel, pulldown resistor and gate driver transistor i get the audio distorted. the opamp look fine, what other things i have to check?

Perry Babin · 12th January 2011, 05:21 PM

Do you have a scope?

stoke · 13th January 2011, 12:42 AM

i bought one, but i'm waiting for the shipping delivered it hasn't arrived yet.
Perry, what component you replace in most case to fix the distortion on one channel, knowing that all transistor, gate resistor, pulldown resistor and gate drivers transistors are good?

help me on, to see if i can fix this one before the tektronik arrives

Perry Babin · 13th January 2011, 11:07 AM

There's no specific component that causes distortion. Which output transistors failed? I need the exact circuit board designation.

Did any 0.1 ohm source resistors fail?

stoke · 13th January 2011, 06:58 PM

yes found 2 of then with a high value

Perry Babin · 13th January 2011, 07:06 PM

When the source resistors open or read significantly higher than they should, you need to check the low value resistors connected to those source resistors. Specifically which of the source resistors (R...?) failed?

stoke · 8th February 2011, 05:11 AM

Finaly i got my scope!!! all the opamps signals look ok the only dif were on gate drivers for audio amp section
this is the measure the same signal on R141 and Q113 gate

maybe later you can tell me how i can fix my scope back light problem, it's a tektronix tds210 i found on ebay with only this problem i hope could be an easy fix.

Perry Babin · 8th February 2011, 05:44 AM

What does the output look like?

I have no information about that scope but if you ask for information on the tekscopes group at Yahoo. Someone there may be able to help. The group is mainly for vintage scopes but some of the members also repair newer scopes.
TekScopes : All about classic Tektronix CRT o'scopes

stoke · 8th February 2011, 04:55 PM

output

Pos

neg

Perry Babin · 8th February 2011, 06:15 PM

Lift D102 and D104. Does that allow the amp to produce audio?

Be careful when doing this. It will defeat the protection circuit and the amp may draw excessive current.

12th January 2011, 05:21 PM	#1
stoke diyAudio Member Join Date: Mar 2010	rockford 501s one bad channel this amp came with one not working channel but after replaced all the transistor of the bad channel, pulldown resistor and gate driver transistor i get the audio distorted. the opamp look fine, what other things i have to check?

12th January 2011, 05:21 PM	#2
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	Do you have a scope? __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

13th January 2011, 11:07 AM	#4
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	There's no specific component that causes distortion. Which output transistors failed? I need the exact circuit board designation. Did any 0.1 ohm source resistors fail? __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

13th January 2011, 07:06 PM	#6
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	When the source resistors open or read significantly higher than they should, you need to check the low value resistors connected to those source resistors. Specifically which of the source resistors (R...?) failed? __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

8th February 2011, 05:44 AM	#8
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	What does the output look like? I have no information about that scope but if you ask for information on the tekscopes group at Yahoo. Someone there may be able to help. The group is mainly for vintage scopes but some of the members also repair newer scopes. TekScopes : All about classic Tektronix CRT o'scopes __________________ 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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13th January 2011, 12:42 AM	#3
stoke diyAudio Member Join Date: Mar 2010	i bought one, but i'm waiting for the shipping delivered it hasn't arrived yet. Perry, what component you replace in most case to fix the distortion on one channel, knowing that all transistor, gate resistor, pulldown resistor and gate drivers transistors are good? help me on, to see if i can fix this one before the tektronik arrives

13th January 2011, 06:58 PM	#5
stoke diyAudio Member Join Date: Mar 2010	yes found 2 of then with a high value

8th February 2011, 05:11 AM	#7
stoke diyAudio Member Join Date: Mar 2010	Finaly i got my scope!!! all the opamps signals look ok the only dif were on gate drivers for audio amp section this is the measure the same signal on R141 and Q113 gate maybe later you can tell me how i can fix my scope back light problem, it's a tektronix tds210 i found on ebay with only this problem i hope could be an easy fix.

8th February 2011, 04:55 PM	#9
stoke diyAudio Member Join Date: Mar 2010	output Pos neg

8th February 2011, 06:15 PM	#10
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	Lift D102 and D104. Does that allow the amp to produce audio? Be careful when doing this. It will defeat the protection circuit and the amp may draw excessive current. __________________ 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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