Hello guys,
first I would like to apologize if I did something wrong (put this thread in wrong section etc.), it is my first post in this forum.
Now to the point. I found similar thread on this forum yet my problem is a bit different. When I turn on the amp I can hear a little crack on both channels, therefore speakers are receiving some signal, however only right channel is working correctly. Left channel stays quiet until I crank up the volume to cca 11 o'clock which is really loud. Then both speakers are equal and everything is fine. Also if I unplug right speaker I can hear that the left one is playing music from cd player but it is VERY quiet.
Now I will describe what I did so far:
Checked all transistors on the output board, all of the output transistors are ok. Checked fuses, diods and all other transistors... everything fine. Then I moved to volume control / input selector board. Checked capacitors, couple of those smd transistors . Switched couple of those ICs which are right next to volume knob (yes I have SMD rework station) to see if different range of volume will start working but no luck... still same problem and at this point I am clueless. Is it right to suspect Z86E21F1 on HA7A control board ?
And also I was not able to find schematics for HA7A only for HA7Z :/ That is why I am running around with multimeter and going trace by trace, shooting blind what could be wrong.
I've already spent couple of days trying to diagnose this amp but at this point I am stuck and dunno where to continue or what to suspect, therefore a bit of help would be appreciated 🙂
Oh, and I am also using PSX-R alongside with Cyrus 3 but that one is fine. I "unmoded" the amp for just the wall plug but problem preserved. Then I switched back to PSX-R configuration.
Thanks in advance for any suggestion.
P.S.: if you guys will need more tech info please let me know. I don't have the amp on my hands right now (writing this from university), therefore I was not able to write which exact components I checked etc.
P.P.S.: Sorry for any grammar error... I am not native English speaker.
first I would like to apologize if I did something wrong (put this thread in wrong section etc.), it is my first post in this forum.
Now to the point. I found similar thread on this forum yet my problem is a bit different. When I turn on the amp I can hear a little crack on both channels, therefore speakers are receiving some signal, however only right channel is working correctly. Left channel stays quiet until I crank up the volume to cca 11 o'clock which is really loud. Then both speakers are equal and everything is fine. Also if I unplug right speaker I can hear that the left one is playing music from cd player but it is VERY quiet.
Now I will describe what I did so far:
Checked all transistors on the output board, all of the output transistors are ok. Checked fuses, diods and all other transistors... everything fine. Then I moved to volume control / input selector board. Checked capacitors, couple of those smd transistors . Switched couple of those ICs which are right next to volume knob (yes I have SMD rework station) to see if different range of volume will start working but no luck... still same problem and at this point I am clueless. Is it right to suspect Z86E21F1 on HA7A control board ?
And also I was not able to find schematics for HA7A only for HA7Z :/ That is why I am running around with multimeter and going trace by trace, shooting blind what could be wrong.
I've already spent couple of days trying to diagnose this amp but at this point I am stuck and dunno where to continue or what to suspect, therefore a bit of help would be appreciated 🙂
Oh, and I am also using PSX-R alongside with Cyrus 3 but that one is fine. I "unmoded" the amp for just the wall plug but problem preserved. Then I switched back to PSX-R configuration.
Thanks in advance for any suggestion.
P.S.: if you guys will need more tech info please let me know. I don't have the amp on my hands right now (writing this from university), therefore I was not able to write which exact components I checked etc.
P.P.S.: Sorry for any grammar error... I am not native English speaker.
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I would start with checking power supplies to components.
Then I would input a sine wave to input then go through system slowly to see where signal dies.
Then I would input a sine wave to input then go through system slowly to see where signal dies.
Thank you for suggestion. I desoldered the pot from board and when I test full range it gives OL. When I try to get resistance according the position of the knob it is pretty much jumping. Sometimes it is 1 ohm. Sometimes 100 ohm, then around 9 o'clock it is OL again etc. Therefore I can assume that the pot is faulty ?
And also... would be somebody so kind to explain why only one channel is malfunctioning when the pot is wrong ?
Thank You 🙂
EDIT: I read here http://www.pinkfishmedia.net/forum/archive/index.php/t-117344.html that the pot on cyrus 3 works completely differently than classic pot.
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