New to the board, but lurking for while trying to find solution to my problem. I have a RF Punch 100 DSM amp. Great little amp. Unfortunately, it powers up but i get no sound. I ordered new all mosfet chips and replaced the BUZZ11's and IRF540's. now i get a very faint audio sound out of of the speakers. in order to hear it i have to put the speaker to my ear. I also ordered the power mosfet chips (L7815CV, VC7915CT, IRF540, and U1610) but have not replaced them as the amp does power up. Wondering if anyone can lend some advice.
Thanks in advance.
Thanks in advance.
If the amp didn't draw excessive current your output and driver transistors are most likely ok. If you have a signal generator and ocilloscope you should trace the input signal forward from the RCA inputs. The amp probably has a defective op amp or may be missing one or more of the supply voltages because of a open trace or bad solder joint.
If one channel works or at least works better use that channel to compare waveforms and voltages to the defective channel. You can pinpoint problems rather quickly with this technique.
Good luck, keep us posted on your progress.
If one channel works or at least works better use that channel to compare waveforms and voltages to the defective channel. You can pinpoint problems rather quickly with this technique.
Good luck, keep us posted on your progress.
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Thanks for the advice/response kds9591.
Unfortunately, the only measuring device I have is a FLUTE MM. No signal generator or ocilloscope. Is here a way to achieve similar testing results with a MM? I have to admit that this is my first attempt at troubleshooting/reapiring an amp. I've installed many remote starters, stereo systems and even replaced IC hips in projection TV's. I'm familiar with soldering/desoldering, etc. I'm not afraid to get in and do the work, just need a bit of guidance.
Unfortunately, the only measuring device I have is a FLUTE MM. No signal generator or ocilloscope. Is here a way to achieve similar testing results with a MM? I have to admit that this is my first attempt at troubleshooting/reapiring an amp. I've installed many remote starters, stereo systems and even replaced IC hips in projection TV's. I'm familiar with soldering/desoldering, etc. I'm not afraid to get in and do the work, just need a bit of guidance.
I've never seen that board with large SMD capacitors in place of the standard, leaded film capacitors. I don't see any corrosion.
Start with the basics...
Do you have both positive and negative rail voltage on the output transistors?
Do you have both positive and negative regulated voltage on the power supply pins of the audio op-amps?
Does operating any of the switches or potentiometers through their entire range make a difference?
Start with the basics...
Do you have both positive and negative rail voltage on the output transistors?
Do you have both positive and negative regulated voltage on the power supply pins of the audio op-amps?
Does operating any of the switches or potentiometers through their entire range make a difference?
Please bare with me a bit I am some what of a noob with the the terminology. I did check the voltage on the power supply pins (middle pins) all two read 12+ V, one read -12V, the fourth read 0. How do I check the rail voltage on the output transistors? With or without the amp connected?
Very faint sound coming out of the left channel speaker. I have to put it up to my ear and listen closely. adjusting the left gain potentiometer does increase it slightly (still need to put it to my ear to hear it) reducing it decreases the sound. No audio whatsoever from the right channel.
thanks
Very faint sound coming out of the left channel speaker. I have to put it up to my ear and listen closely. adjusting the left gain potentiometer does increase it slightly (still need to put it to my ear to hear it) reducing it decreases the sound. No audio whatsoever from the right channel.
thanks
You measure voltages with power applied to the amp (amp on unless otherwise specified).
You measure resistances with no power applied.
Spell out, very specifically, what you don't understand and I'll try to help. Don't short-hand anything. Be very clear about what you don't understand. Separate each question from the one before with a blank line.
If you haven't done so already, read the basic amp repair page (link in sig file below).
You measure resistances with no power applied.
Spell out, very specifically, what you don't understand and I'll try to help. Don't short-hand anything. Be very clear about what you don't understand. Separate each question from the one before with a blank line.
If you haven't done so already, read the basic amp repair page (link in sig file below).
Perry,
Thanks for the response and advice. I will measure voltages and resistances per your request and advise on results.
I will also be very specific on the things i don't understand and separate questions individually.
With your help, I'm sure i'll be able to figure this one out. Thanks again.
Thanks for the response and advice. I will measure voltages and resistances per your request and advise on results.
I will also be very specific on the things i don't understand and separate questions individually.
With your help, I'm sure i'll be able to figure this one out. Thanks again.
If you can read a schematic Perry or someone else may have it for this amp and can e-mail it to you or you can get it e-mailed to you from Rockford. It would help you a lot, most brands of car amps you can't get a schematic for, Rockford is one of the few brands you can.
Also read Basic Car Audio Repair using the link in Perry's signature line. He also has a Basic Car Amp Repair course as well. Very good information and excellent real world examples & solutions.
Also read Basic Car Audio Repair using the link in Perry's signature line. He also has a Basic Car Amp Repair course as well. Very good information and excellent real world examples & solutions.
Perry,
Sorry, work got the best of me this week.
See below this is where i'm at for now:
Rail voltage on the output transistors (third leg of IRF540's)? With red lead of MM to B+ on amp and black lead to third leg of Mosfet chip
Q103 =12.18V
Q104 =12.18V
Q107 =44.9V
Q106 =44.9V
Q206 =44.9V
Q207 =44.9V
Q204 =12.16V
Q203 =12.16V
Regulated voltage on the power supply pins of the audio op-amps? Not sure how to measure or what pin orientation is.
Left Channel (LM833)
Right Channel (LM833)
Does operating any of the switches or potentiometers through their entire range make a difference?
Right Channel potentiometers work only. you can hear the low to high range but still need to hold speaker to your to hear.
Sorry, work got the best of me this week.
See below this is where i'm at for now:
Rail voltage on the output transistors (third leg of IRF540's)? With red lead of MM to B+ on amp and black lead to third leg of Mosfet chip
Q103 =12.18V
Q104 =12.18V
Q107 =44.9V
Q106 =44.9V
Q206 =44.9V
Q207 =44.9V
Q204 =12.16V
Q203 =12.16V
Regulated voltage on the power supply pins of the audio op-amps? Not sure how to measure or what pin orientation is.
Left Channel (LM833)
Right Channel (LM833)
Does operating any of the switches or potentiometers through their entire range make a difference?
Right Channel potentiometers work only. you can hear the low to high range but still need to hold speaker to your to hear.
Never use the B+ terminal as the reference. In general, you use the amplifier's ground terminal as the reference. That means that you place the black meter probe on the amp's ground terminal.
If you're not sure of the pin configuration for any op-amp, search for 'datasheet' and the number on the IC.
datasheet lm833 - Google Search
http://www.national.com/ds/LM/LM833.pdf
For the LM833, the power supply pins are 4 and 8.
What are you using for a signal source?
If you're not sure of the pin configuration for any op-amp, search for 'datasheet' and the number on the IC.
datasheet lm833 - Google Search
http://www.national.com/ds/LM/LM833.pdf
For the LM833, the power supply pins are 4 and 8.
What are you using for a signal source?
Do you have a sine wave test tone track?
If not, use this one:
http://www.bcae1.com/temp/100hz300seconds.zip
Drive a signal into the amp and measure the AC voltage on the terminals on the back of the RCA jacks. What's the highest voltage the itouch can produce without clipping/distorting? You may have to listen to it via headphones to see where it clips if you don't have a scope.
If not, use this one:
http://www.bcae1.com/temp/100hz300seconds.zip
Drive a signal into the amp and measure the AC voltage on the terminals on the back of the RCA jacks. What's the highest voltage the itouch can produce without clipping/distorting? You may have to listen to it via headphones to see where it clips if you don't have a scope.
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