I listened to your wav file. I truly wish I had a clue why this is happening. I have never encountered this before.
I have used blu ray player as a source for testing purposes.
Not sure what dc offset is supposed to be there but my cheap mmeter reads voltage swing from microvolts to 1+ V on at the end of rca's. Both.
Not sure what dc offset is supposed to be there but my cheap mmeter reads voltage swing from microvolts to 1+ V on at the end of rca's. Both.
DC offset through a LDR attenuator should be absolutely the same as the output from your source so if you remove the attenuator and measure that of the source you will see what you should be getting when the attenuator is attached. If your source does not have a DC offset problem AND there is a DC offset problem at the output of your LDR attenuator then something is WRONG and pictures are required. Good pictures.
It is not a source.
This occurs after I increase vol a tiny bit...
Here is the link to the large pic of my vcpre in cardboard box...
https://www.dropbox.com/s/wtrz16yj6sgp2nn/IMGP2583.JPG
This occurs after I increase vol a tiny bit...
Here is the link to the large pic of my vcpre in cardboard box...
https://www.dropbox.com/s/wtrz16yj6sgp2nn/IMGP2583.JPG
Rudi is there a situation that would cause the processor to turn on and off? Maybe a defective 7805 or perhaps fluorescent lights messing with the IR receiver? I just ran into a bunch of work that will keep me busy today but if I get a chance to reply and I have something constructive to say I will try.
Not sure if it makes a difference, but from the picture it looks like your trim pot is soldered the wrong way round (on mine the screw is to the right) .
Mat
Mat
Mat: the trim-potentiometer is o.k.
Uriah: I do not know about any situation that would "reset" the processor.
The processor has a reset input, but this input is pulled up to 5VDC according to the datasheet.
Ivan: your music source is connected to the leftmost relay, the standard name of which is "AUX".
So you must have changed the source via your remote control to access this relay.
The standard selection after PowerOn or Reset is the rightmost relay, which is associated with "CDP".
What is your display showing after increasing the volume? Does it still show "AUX"?
Best regards - Rudi
Uriah: I do not know about any situation that would "reset" the processor.
The processor has a reset input, but this input is pulled up to 5VDC according to the datasheet.
Ivan: your music source is connected to the leftmost relay, the standard name of which is "AUX".
So you must have changed the source via your remote control to access this relay.
The standard selection after PowerOn or Reset is the rightmost relay, which is associated with "CDP".
What is your display showing after increasing the volume? Does it still show "AUX"?
Best regards - Rudi
Hi.
It was the same both aux and cdp and after I inrease vol it shows attenuation.
Actually no need to vol increase as this effect kicks in any way.
I remember I still have the other ic (will send it back to you Rudi I promise) and it has the same problem.
Attenation shows as minus 16.
Actually it stays constant. Checked it now and while vol increase numbers remain same. Last time it was similar only dB increase appeared on the very end of turn of the pot.
For instance other ic had 0 dB constantly but I need to put it back again to confirm it.
Update: attenuation numbers change but it happens in the last 1/5 of the turn or even less
It was the same both aux and cdp and after I inrease vol it shows attenuation.
Actually no need to vol increase as this effect kicks in any way.
I remember I still have the other ic (will send it back to you Rudi I promise) and it has the same problem.
Attenation shows as minus 16.
Actually it stays constant. Checked it now and while vol increase numbers remain same. Last time it was similar only dB increase appeared on the very end of turn of the pot.
For instance other ic had 0 dB constantly but I need to put it back again to confirm it.
Update: attenuation numbers change but it happens in the last 1/5 of the turn or even less
Last edited:
Ivan: the display of the volume attenuation does not work properly, as I have
mentioned many times before.
At low or normal volume level the increase of the volume results in a very, very small increase of current
(in the range of some µA) that flows through the LDRs - LED.
This small current-increase cannot be monitored by the MCP6021 and the µProcessor's internal A/D converter.
Only when you turn the volume very loud and each turn of the potentiometer results in some mA (!) increase
of LED-current, the display shows a change.
Is the display of the volume attenuation the only problem that you have?
Best regards - Rudi
mentioned many times before.
At low or normal volume level the increase of the volume results in a very, very small increase of current
(in the range of some µA) that flows through the LDRs - LED.
This small current-increase cannot be monitored by the MCP6021 and the µProcessor's internal A/D converter.
Only when you turn the volume very loud and each turn of the potentiometer results in some mA (!) increase
of LED-current, the display shows a change.
Is the display of the volume attenuation the only problem that you have?
Best regards - Rudi
It's not your only problem. You have a larger problem with the oscillation (it seems oscillation to me).
Does the problem happen 30s after power on or 30s after music start? Seems odd that it takes time to occur unless something is happening in the meantime like a capacitor charging.
You could try it in another enclosure, that box looks quite shiny, maybe some sort of charge is building up?
Good luck,
Mat
You could try it in another enclosure, that box looks quite shiny, maybe some sort of charge is building up?
Good luck,
Mat
If to accept the notion what I made a mistake in soldering what part or combination of parts could cause this in theory ?
Hi Voxx, C8 on the bom is a 2.2uF tant bead, the board i have has no polarity markings for that cap, you got it the right way around? looks like neg should go to the outside of the pcb.
With tantalum bead caps the +ve is marked unlike electrolytics (-ve).
Andrew
With tantalum bead caps the +ve is marked unlike electrolytics (-ve).
Andrew
Actually it might be reversed.
I ll check it tomorrow. Dont want to wake up daughter.
If cap is reversed it might explain delayed appearance of the problem ?
And ifit is true can I reverse it back or cap is damaged most likely?
I ll check it tomorrow. Dont want to wake up daughter.
If cap is reversed it might explain delayed appearance of the problem ?
And ifit is true can I reverse it back or cap is damaged most likely?
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