GraphicMan
Senior Member
Last Activity: 06-03-2024, 06:23 AM
Joined: 08-06-2018
Location: Cairo
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it turned out that the cause of the noise is from the pc and not the amplifier... -
Pioneer A-205 faint noise/hiss issue
as the title says, i noticed a faint noise/hiss when there is nothing playing that i dont think i have had with this unit before ever, i have not changed its location
what makes it more weird, this noise is gone almost completely if my hand gets within 5cm or less close to it (close to the panel)!!
out of curiosity what does that mean?
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hmm i found the problem
it is from the "good" end of the same cable i fixed its other end, the connector looks so intact but i discovered the problem when it twist, so aparently it needs to be cut and remade, i know i have not done anything wrong in the assembly it is just that cable is so evil, it never failed the dmm tests also
but the unit is working great now
thank you very much...Leave a comment:
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I have checked also that cable and the connectivity is correct
this is the large cable from the back pcb to the top one
could the problem be from a tiny transistor on the main board? i have seen a video with a channel not working and a transistor was the issue
i am stuck here now, plz help...Leave a comment:
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ok i am back to a good middle point
i found a bad connector! which made all the late issues
i fixed it properly and now i am back to:
just no left channel, headphones are very good, no relay issues, overall sound quality and volume really good, no noises from the pot at all
i have blobbed the direct switch pins so i am testing now with much less possible issues
where the problem could be?
i tried to move the other larger cable which looks good but nothing at all at that channel, i think if the input was the problem i would never get signals from both channels...Leave a comment:
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I also removed the headphone jack, just to get it out of the equation (however it is good)Leave a comment:
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plz dont forget to tell me about these 2 pins specifically coz i did something, i desoldered both using the copper wick (completely clean) and i did test the switch (both pins isolated from the pcb), and it works perfectly it does d/c and connect them so the short is not from the switch, however when i test the pads continuity they are always connected, so i want to know if that is ok or they should not be connected all the time at any state
the other pin does d/c / connect, the other B switch is perfect also, it is important coz it could mean something, however like i said keeping A on...Leave a comment:
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this is the best i could find with my limited knowledge in schematic drawings for the direct switch pins
but here it is rotated compared to the pcb pic i shared, is the small + means connected together? and on which state is that? off by default
just trying to learn something new
thanks...Leave a comment:
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in addition:
also here is a pic for the front panel, showing the 12 pins
i would like to first solder them to the "direct switch" OFF state without using the switch, just to make sure and make it easy to diagnose
plz let me know how should i blob / wire them without the switch, just mark for me the connected pins and i will do it
thanks...Leave a comment:
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ok finally some good news
i re soldered again and add a re flowing /soldering to the relay pins and some other pins that looks they have little solder (close to the connector)
there is sound on both channels , but for few seconds and when i tried to press on the direct switch there was noises (which is not news, i know it have issues) but the news is that the relay started to go on/off quickly, so i decided to power off the unit immediately to check
now i removed the direct switch
and disassembled it, it is complex and have 12 pins!
for that i need to know what is...Leave a comment:
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i am assuming that "x" issue (connected all the time) should not be the problem coz whether A switch is on or off the output is not affected as far as B switch is good and ON and that by itself is worrying me...Leave a comment:
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i thought to test the connectivity of these switches
B is perfect which is the one i am using all the time
A connect / disconnect only the one marked right, X is always ON no matter what
is that right or wrong? can this cause all that issues including the very faint sound on the phones?
i really dont want to pull these out unless i am sure it is the issue coz it is a lot of work
the 2 switches are both crimped to a single steel plate, for that i will have to desolder the 12 pins at the same time in order to be able to pull it out!
thanks...Leave a comment:
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relay still works normallyLeave a comment:
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hmm, this is getting a bit strange and also very frustrating
guess what
i re soldered all pins on the jack/speaker switches pcb as well as all the pins of the connectors on the attached pic (inside the rectangles)
and now i dont have any output on the speakers!!!, kept clicking on the speaker switches, nothing at all
on top of that, when i tested again with the headphones, the sound is very very faint! unlike the last time!!!!!
what does that mean?!!...Leave a comment:
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it does not have a relay, perhaps bad contact also, good point from you
i just need to solve the L channel at the point, very annoyed
thanks...Leave a comment:
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ok i found the connector u meant, it is on the pic i sent
R makes sound, L no sound when touched!
so?Leave a comment:
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i also want to add a side note that i notice now and also before
I am actually connected a tweeter and a sub woofer in parallel to every channel, i know u might disagree with that setup but that works perfectly and the tweeter is not overloaded or anything, however latetly before that thread , there was scratchy noises due to the switches as well as the pot, i cleaned these but one thing sometimes happen which is the tweeters works but not the subwoofer until i boost the volume and get it started then i can lower the volume normally, it could be from the pot or scratchy switches still but...Leave a comment:
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dont know if that is a good or a bad news, i did not find the converter so i used these 3 pins as mentioned in the pic and there is clear sound coming to the head phones from both left and right pins
plz confirm that my assumption is correct on these pins
this means there is no issue in the path of the input signal?
if so, where is the problem then?!
can you please guide me where is that AKP1044 connector on the actual pcb?
attached is the pcb after cleaning and re flowing some joints (already tested and worked at that stage before the assembly)
...Leave a comment:
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the speaker switches has no effect also , on top of that i never had any scratchy noises from the speaker switches also
they are just A and B, i am always using the B, and it works but on right channel only
i have an earphone but with the small jack, i think i have a converter, will try and let u know
thanks...Leave a comment:
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btw there is actually a much cleaner version of the schismatics R_J shared it
[URL]https://elektrotanya.com/pioneer_a-103_a-203.pdf/download.html[/URL]
in case it helpshttps://btw there is actually a much... case it helpsbtw there is actually a much cleaner version of the schismatics R_J shared it
[URL]https://elektrotanya.com/pioneer_a-103_a-203.pdf/download.html[/URL]
in case it helps...Leave a comment:
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