I mistakingly attached the '99...I edited it right away but I guess you are too fast
Thanks a lot!
I replaced Q10 and the amp is fine.
There is another problem with this amp, sometimes it leaves one half of the waveform out on the left channel.
It seems like its ok with a continuous input signal, but if i use a bursted 1kHz signal with 20ms , the firs 3 cycles are ok and then the next cycles drop
extremely to near zero and then start to grow up the longer the burst signal is.
I will take a screenshot of the sope. Its weird because it is not always and with music everything looks ok.
Thanks so far!!
Screenshots:
left channel 1 kHz and with a 40Hz burst it gets more worse, last pic is mono 4 ohm 1 kHz burst.
I replaced Q10 and the amp is fine.
There is another problem with this amp, sometimes it leaves one half of the waveform out on the left channel.
It seems like its ok with a continuous input signal, but if i use a bursted 1kHz signal with 20ms , the firs 3 cycles are ok and then the next cycles drop
extremely to near zero and then start to grow up the longer the burst signal is.
I will take a screenshot of the sope. Its weird because it is not always and with music everything looks ok.
Thanks so far!!
Screenshots:
left channel 1 kHz and with a 40Hz burst it gets more worse, last pic is mono 4 ohm 1 kHz burst.
Last edited:
Yes, the other channel produced rated power with ease.
Sometimes the left channel is also producing rated power at 4 ohm.
Testing with lower power levels everything is ok.
It seems like the amp needs some time ( around 400ms to produce a full waveform ).
Testing with 40Hz took the amp down much earlier.
Sometimes the left channel is also producing rated power at 4 ohm.
Testing with lower power levels everything is ok.
It seems like the amp needs some time ( around 400ms to produce a full waveform ).
Testing with 40Hz took the amp down much earlier.
Yes!
Desoldering the diode leads to clean cycles. 😀
I guess this diode is leading to a protection circuit?
With a 4 ohm load it sometimes was clean, with a 2 ohm load it was always bad after 4-5 cycles.
i am not familiar with this, but i think i had polarity wrong, so it was a little missleading to get the right diode, i also desoldered D202 before because i forgot
what my polarity was.
Should i check for bad resistors after D205 ?
Is it possible to spend you some coffees or beers via Paypal?
Im really happy that you are supporting me with your great experience , i learned a lot and in my opinion just writing " thank you very much " is not enough - Again thank you for your time 👍
Desoldering the diode leads to clean cycles. 😀
I guess this diode is leading to a protection circuit?
With a 4 ohm load it sometimes was clean, with a 2 ohm load it was always bad after 4-5 cycles.
i am not familiar with this, but i think i had polarity wrong, so it was a little missleading to get the right diode, i also desoldered D202 before because i forgot
what my polarity was.
Should i check for bad resistors after D205 ?
Is it possible to spend you some coffees or beers via Paypal?
Im really happy that you are supporting me with your great experience , i learned a lot and in my opinion just writing " thank you very much " is not enough - Again thank you for your time 👍
Did you check all of the 0.1 source resistors (may have to desolder to be accurate) to confirm that they're within tolerance?
Did you check R264, R265 (and parallel diodes) to confirm that none were out of tolerance?
Thanks but I'm longer allowed to have either coffee or beer.
Did you check R264, R265 (and parallel diodes) to confirm that none were out of tolerance?
Thanks but I'm longer allowed to have either coffee or beer.
Hi Perry!
It was hard to check the 0.1 ohm resistors but they all measure the same, the value varies from 0,085 to 0,125 depending on the zero setting of my DMM.
I lifted D205 and R 266 to R 274 showed the same values, so i think they are fine.
I also noticed that i had to desolder D305 to get clean cycles , D302 and D202 are soldered to the board and with D305 & D205 desoldered, everything is fine now!
I also checked R366 to R374 , they also check good.
Also R264 and R265 are within tolerance and R364 and R365 also.
The diodes check also ok. i dont know what i missed
Do i also have to check the 0.1 Resistors which are located nearby D202 and D302 ?
Mono 4 ohms i got more than 1000 watts with a short burst and clean cycles
It was hard to check the 0.1 ohm resistors but they all measure the same, the value varies from 0,085 to 0,125 depending on the zero setting of my DMM.
I lifted D205 and R 266 to R 274 showed the same values, so i think they are fine.
I also noticed that i had to desolder D305 to get clean cycles , D302 and D202 are soldered to the board and with D305 & D205 desoldered, everything is fine now!
I also checked R366 to R374 , they also check good.
Also R264 and R265 are within tolerance and R364 and R365 also.
The diodes check also ok. i dont know what i missed
Do i also have to check the 0.1 Resistors which are located nearby D202 and D302 ?
Mono 4 ohms i got more than 1000 watts with a short burst and clean cycles
Isn't the problem only in the left channel? Why are you having to make changes to the right channel (300 series components)?
Yes it was confusing.
first i tested one channel 4 ohms and the problem occured on the 200 channel but not always. With 2 ohms per channel it occured always.
After that i made a test mono 4 ohms ( still thinking 300 channel is ok ) and i lifted diodes one at a time and thought after desoldering D205 everything was ok.
I resoldered D202 and D302 , everthing was fine, I resoldered D305 and the cycles were still gointg down. So i doublechecked it and i have to leave D205
and D305 out of the circuit to get clean cycles.
first i tested one channel 4 ohms and the problem occured on the 200 channel but not always. With 2 ohms per channel it occured always.
After that i made a test mono 4 ohms ( still thinking 300 channel is ok ) and i lifted diodes one at a time and thought after desoldering D205 everything was ok.
I resoldered D202 and D302 , everthing was fine, I resoldered D305 and the cycles were still gointg down. So i doublechecked it and i have to leave D205
and D305 out of the circuit to get clean cycles.
Are you using a speaker or are you using a dummy load as a test load?
Does the right channel clip the top of the signal in 2 ohms (only the right channel driven)?
Does the right channel clip the top of the signal in 2 ohms (only the right channel driven)?
I have some 1000 watts 1 ohm resistors and i connected four 1 ohm in series to test 4 ohm mono.
I didnt drive it into clipping. should i resolder the diodes and test both channels again with two ohms?
It was weird that this problem only occured with burst testing, with continuous input signal it was sometimes fine.
I didnt drive it into clipping. should i resolder the diodes and test both channels again with two ohms?
It was weird that this problem only occured with burst testing, with continuous input signal it was sometimes fine.
Clipping refers to the top of the wavefom being clipped/missing.
What does the amp do with speakers?
What does the amp do with speakers?
With music it sounds good, all waveforms are present and unclipped.
But i wasnt able to test higher power levels with music and a speaker connected, i will get killed by neighbours 🙂
But i wasnt able to test higher power levels with music and a speaker connected, i will get killed by neighbours 🙂
hmmm.... i had a working 800 and 1000 tested the same way.
Every rockford amp was able to put out dynamic power mono 4 ohms and way more than they are rated into the dummy load.
Every rockford amp was able to put out dynamic power mono 4 ohms and way more than they are rated into the dummy load.
Hi!
I have to continue the troubleshooting.
Today i was able to test the 800 with a 4 ohm 18" subwoofer with enough power.
I used the same settings like the method i tested with my dummy load.
I resoldered D305 and this happens with a 4 cycle 40Hz burst
I think i have to desolder all 0.1ohm resistors and test them with constant current and measure the voltage across them to get more accurate readings.
Its not possible with the Fluke to get good readings 🙁
I have to continue the troubleshooting.
Today i was able to test the 800 with a 4 ohm 18" subwoofer with enough power.
I used the same settings like the method i tested with my dummy load.
I resoldered D305 and this happens with a 4 cycle 40Hz burst
I think i have to desolder all 0.1ohm resistors and test them with constant current and measure the voltage across them to get more accurate readings.
Its not possible with the Fluke to get good readings 🙁
Attachments
Recheck all of the protection circuit resistors while you have the source resistors out of the circuit.
I borrowed a higher resolution DMM and found one source resistor out of tolerance , R342. It was 0.234 ohm instead of 0.100 ohm.
Now i have strange behavior:
If i put a continuous 1kHz into the amp, the positive and negative waveform clip equally at a little more than 830 watts, so everything ist fine.
If i put a 1kHz burst with 20 cycles into the amp the first 4 cycles are ok and the rest is down, same like in last pic of #42.
This is with one burst in 1 second.
If i send 5 bursts per second, then i get 10 clean cycles and the rest is down.
If i send 15 bursts per second i get all 20 cycles clean.
Its crazy , i never faced such a behavior.
If i start continuous test immediately with a high level, it leaves the waveform out.
If i slowly start with low level and increase gain to the clipping point, everything is fine.
Now i have strange behavior:
If i put a continuous 1kHz into the amp, the positive and negative waveform clip equally at a little more than 830 watts, so everything ist fine.
If i put a 1kHz burst with 20 cycles into the amp the first 4 cycles are ok and the rest is down, same like in last pic of #42.
This is with one burst in 1 second.
If i send 5 bursts per second, then i get 10 clean cycles and the rest is down.
If i send 15 bursts per second i get all 20 cycles clean.
Its crazy , i never faced such a behavior.
If i start continuous test immediately with a high level, it leaves the waveform out.
If i slowly start with low level and increase gain to the clipping point, everything is fine.