PPI Art 600 R121 ..... what ohm is it????

o. l. t. · 6th May 2010, 02:43 AM

I believe I am about to fix the popping and static in my channel with this resistor. What ohm is R121 please? PLEASE

o. l. t. · 6th May 2010, 03:45 AM

Confirmed it is ten ohm, replaced, no change. I cannot get that channel to stop popping. Even if I pull the rca's out it sits there and pops in a similar manor to dust in a gain knob. Any ideas?

Perry Babin · 6th May 2010, 10:56 AM

Do you have a scope or some way to trace the signal?

o. l. t. · 6th May 2010, 04:45 PM

Hi perry. I certainly do I just need a little guidance.

Perry Babin · 6th May 2010, 05:01 PM

Do you have a clean audio signal (no popping or pulsing) on the terminals or those large capacitors?

Set your scope to 1v/div.

Does it do it on both channels?

o. l. t. · 6th May 2010, 05:06 PM

Only the left channel. Subwoofer shows a little dc bias pushing out slightly when connected.

Perry Babin · 6th May 2010, 05:12 PM

Compare the signal on the left channel to the signal on the right channel (on their orange capacitors). Do you see pulsing DC at that point on either channel?

o. l. t. · 09:46 PM

With the Fluke at amp ground, and no rca's, one channel is a tad different at idle with no input.

As far as what I have to work with, pretty much whatever I need. I just DO NOT repair audio and I need all the counseling I can get.

Techtronix 442 is a dual trace, and the TENMA 72-7290 has counter, generator, DMM and PS. I have my Fluke 87 III as well.

o. l. t. · 09:57 PM

Actually q33 just went hot potato on me with a little smoke, but I cut it off almost instantly so it got real hot but I think it is still alive. It's the only one that got hot. No foreseeable reason so can I assume that is the final that was going out and causing the trouble? Nothing else in the row got warm. The amp was only on for about ten seconds total, and I was probing the orange capacitor with my flukes + and the negative connected to the amp ground with the meter on DCv. Unless it has dc bias or something from the fluke, which I doubt.

Perry Babin · 6th May 2010, 09:57 PM

Look at the signal on the cap. Do you see the same characteristics as you do on the speaker terminals of the defective channel. This is to determine if the channel is being driven with a pulsing signal or if the pulsing is due to something else.

Did you check the output transistors carefully?

6th May 2010, 02:43 AM	#1
o. l. t. diyAudio Member Join Date: Dec 2009	PPI Art 600 R121 ..... what ohm is it???? I believe I am about to fix the popping and static in my channel with this resistor. What ohm is R121 please? PLEASE

6th May 2010, 10:56 AM	#3
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	Do you have a scope or some way to trace the signal? __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

6th May 2010, 05:01 PM	#5
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	Do you have a clean audio signal (no popping or pulsing) on the terminals or those large capacitors? Set your scope to 1v/div. Does it do it on both channels? __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

6th May 2010, 05:12 PM	#7
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	Compare the signal on the left channel to the signal on the right channel (on their orange capacitors). Do you see pulsing DC at that point on either channel? __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

6th May 2010, 09:43 PM	#8
o. l. t. diyAudio Member Join Date: Dec 2009	With the Fluke at amp ground, and no rca's, one channel is a tad different at idle with no input. As far as what I have to work with, pretty much whatever I need. I just DO NOT repair audio and I need all the counseling I can get. Techtronix 442 is a dual trace, and the TENMA 72-7290 has counter, generator, DMM and PS. I have my Fluke 87 III as well. Last edited by o. l. t.; 6th May 2010 at 09:46 PM.


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6th May 2010, 03:45 AM	#2
o. l. t. diyAudio Member Join Date: Dec 2009	Confirmed it is ten ohm, replaced, no change. I cannot get that channel to stop popping. Even if I pull the rca's out it sits there and pops in a similar manor to dust in a gain knob. Any ideas?

6th May 2010, 04:45 PM	#4
o. l. t. diyAudio Member Join Date: Dec 2009	Hi perry. I certainly do I just need a little guidance.

6th May 2010, 05:06 PM	#6
o. l. t. diyAudio Member Join Date: Dec 2009	Only the left channel. Subwoofer shows a little dc bias pushing out slightly when connected.

6th May 2010, 09:54 PM	#9
o. l. t. diyAudio Member Join Date: Dec 2009	Actually q33 just went hot potato on me with a little smoke, but I cut it off almost instantly so it got real hot but I think it is still alive. It's the only one that got hot. No foreseeable reason so can I assume that is the final that was going out and causing the trouble? Nothing else in the row got warm. The amp was only on for about ten seconds total, and I was probing the orange capacitor with my flukes + and the negative connected to the amp ground with the meter on DCv. Unless it has dc bias or something from the fluke, which I doubt. Last edited by o. l. t.; 6th May 2010 at 09:57 PM.

6th May 2010, 09:57 PM	#10
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	Look at the signal on the cap. Do you see the same characteristics as you do on the speaker terminals of the defective channel. This is to determine if the channel is being driven with a pulsing signal or if the pulsing is due to something else. Did you check the output transistors carefully? __________________ 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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