pioneer sx1080 help...
- Thread starter gene french
- Start date
- Joined
- Jan 14, 2011
- Messages
- 74,934
- Location
- Gillette, Wyo.
- Tagline
- Halfbiass...Electron Herder and Backass Woof
Gene...did you do everything Mark suggested in the order he suggested it? I have not seen Mark fail at one of these hand holding projects. If Mark has decided to help you I would not take that lightly, he doesn't have a lot of spare time, if you blow off his help you won't get it again, and he's THE GUY on a Pioneer receiver....
- Joined
- Apr 1, 2015
- Messages
- 133
- Tagline
- ---
I've been doing this online at audiokarma since 2005. good garsh!!! seventeen years!!!
The best advice I can give you right now, is to replace those gwg-112 "Flat amplifier" Q3 and Q4 2sa726's with the a992's that came in the kit.
The kitmaker (I think I know who, peace.love.and.music, right?) did you a solid by including them.
I cannot stress this enough - the replacement 992 transistor has the opposite pinout as the original 2sa726.
It is best to go from the symbol on the sx-1080's PC board to install these two transistors.
Here's an sx-1080 picture fragment of that transistor in it's board. With the blue dot.
The 2sa726 is BCE
The symbol on the board: the emitter has the arrow
the base is the flat line that the arrow exits on an angle
the collector is the other flat line with no arrow at the opposite angle exiting the base line.
The ksa992 is ECB
I hate saying it this way, face the flat in the opposite direction.
The best advice I can give you right now, is to replace those gwg-112 "Flat amplifier" Q3 and Q4 2sa726's with the a992's that came in the kit.
The kitmaker (I think I know who, peace.love.and.music, right?) did you a solid by including them.
I cannot stress this enough - the replacement 992 transistor has the opposite pinout as the original 2sa726.
It is best to go from the symbol on the sx-1080's PC board to install these two transistors.
Here's an sx-1080 picture fragment of that transistor in it's board. With the blue dot.
The 2sa726 is BCE
The symbol on the board: the emitter has the arrow
the base is the flat line that the arrow exits on an angle
the collector is the other flat line with no arrow at the opposite angle exiting the base line.
The ksa992 is ECB
I hate saying it this way, face the flat in the opposite direction.
That’s an important detail…
And the flat is there to assist non-electrical engineers (like me) to install them correctly. Same as longer leads and racing stripes on caps to indicate polarity.
Very gracious of you to describe that so clearly and completely!
I bet my SX-880 has these and I should be changing them out…
And the flat is there to assist non-electrical engineers (like me) to install them correctly. Same as longer leads and racing stripes on caps to indicate polarity.
Very gracious of you to describe that so clearly and completely!
I bet my SX-880 has these and I should be changing them out…
- Joined
- Mar 6, 2022
- Messages
- 5,566
- Tagline
- music...the healer of souls...
- Joined
- Mar 6, 2022
- Messages
- 5,566
- Tagline
- music...the healer of souls...
yes sir...i did replace the 726s with the 992s....as per your suggestion...
i bought the kit on ebay but not from peace.love... from a guy whose first name is william...he included the data sheets...and i had no problem installing the replacements....the 1080 performed as before...playing music but no right channel in the stereo mode...
i recleaned all pots and switches...i did pinout both tape monitor switches as well as the stereo mono switch...they show they are making contact and releasing contact depending on their position...
in the mono mode...all other functions work...except noise on am radio...though the meter shows signal...
balance works...tone works...tone bypass....loudness...20db attenuation works...
i did check for broken wires...and bad traces....i searched for open resistors on the flat amp board....as i found two on the driver board...
i am still using the dim bulb tester.....so i know my voltage might be a tad low...but, i dont think that would stop the right channel from playing...
guys, please dont mislabel me....i am not a tech...just in a place where vintage techs are non existant....this is a very small place and still classified as a third world country....i am doing the best i can....and i dont mean to ignore, insult, or belittle anyone....i try in every post to show my gratitude for the attention and help...and i hope to resolve the issues with your assistance....the 1080 was recapped in november....takes a while to get parts here...the journey has been a slow one...
i am making progress....
thanks all of you for contributing and helping ....
i appreciate the hand holding...
i bought the kit on ebay but not from peace.love... from a guy whose first name is william...he included the data sheets...and i had no problem installing the replacements....the 1080 performed as before...playing music but no right channel in the stereo mode...
i recleaned all pots and switches...i did pinout both tape monitor switches as well as the stereo mono switch...they show they are making contact and releasing contact depending on their position...
in the mono mode...all other functions work...except noise on am radio...though the meter shows signal...
balance works...tone works...tone bypass....loudness...20db attenuation works...
i did check for broken wires...and bad traces....i searched for open resistors on the flat amp board....as i found two on the driver board...
i am still using the dim bulb tester.....so i know my voltage might be a tad low...but, i dont think that would stop the right channel from playing...
guys, please dont mislabel me....i am not a tech...just in a place where vintage techs are non existant....this is a very small place and still classified as a third world country....i am doing the best i can....and i dont mean to ignore, insult, or belittle anyone....i try in every post to show my gratitude for the attention and help...and i hope to resolve the issues with your assistance....the 1080 was recapped in november....takes a while to get parts here...the journey has been a slow one...
i am making progress....
thanks all of you for contributing and helping ....
i appreciate the hand holding...
- Joined
- Jan 14, 2011
- Messages
- 74,934
- Location
- Gillette, Wyo.
- Tagline
- Halfbiass...Electron Herder and Backass Woof
- Joined
- Jan 14, 2011
- Messages
- 74,934
- Location
- Gillette, Wyo.
- Tagline
- Halfbiass...Electron Herder and Backass Woof
- Joined
- Apr 1, 2015
- Messages
- 133
- Tagline
- ---
Ok. installing the ksa992 didn't get the right channel sound back. Still no right channel.
This is getting tougher, the kits generally cover the troublemakers.
We're going to use a different method now. We are going to be injecting BUZZZZ from hum from your finger into the quiet channel. Working backwards.
When the buzz no longer comes out of the speaker, we have crossed the point where the audio gets lost.
first place is the pre-out / amp-in jumpers smack dab in the middle of the back of the unit.
touch a wetted finger to each bare metal jumper, one at a time. should get buzz from one speaker when doing this.
To prove the concept works and that your finger is noisy enough.
If your finger is too wide, straighten out a paper clip
(tape up the business end, all but the end of the tip to avoid shorting anything out by touching TWO things at once).
I'm not going to post the picture I'm using for this (unless you ask) , you have successfully navigated the innards of the SX-1080 doing the kit.
If I lose you, speak on up, it's my mistake in not describing it well enough.
After navigating the list I am going to post, we can confirm bad parts by swapping them with good parts borrowed from the working channel temporarily.
Also the list will seem to jump around a bit (binary search?), but we want to get past whole bunches of working circuits quickly. Like the tone amp and filters.
This is all stuff easily accessible with an open bottom of the SX-1080.
Tone control board, where the tone controls are mounted on, near the power switch.
AWG-056 tone control inputs are pin 8 (white wire) for left channel, pin 6 (red?pink? wire) for right channel.
AWG-056 tone control outputs are pin 5 (yellow wire) for left channel, pin 3 (violet wire) for right channel.
touch pin 8, then touch pin 6 hear the buzz? can tone controls affect the buzz when turned on?
if not, touch pin 5, then pin 3 to check that the output of the tone board can buzz.
Now we're going to jump to the volume control board. There are white and red?pink? wires at pins 6 & 8 (again!!) of the GWG-112. They are the opposite ends of the red?pink? (R) and white (L) wires feeding the tone control. Touch them and confirm each hums.
now we are going to find the volume control sliders. And inject hum into them
The red circled pins are the volume control pins, with channel identifiers. One is hidden (just from view) under the face plate bottom.
The circled caps are the next components after the tap, then there is a resistor and then the jfet gate.
touch the red circles to inject hum on the left and right channels.
This is getting tougher, the kits generally cover the troublemakers.
We're going to use a different method now. We are going to be injecting BUZZZZ from hum from your finger into the quiet channel. Working backwards.
When the buzz no longer comes out of the speaker, we have crossed the point where the audio gets lost.
first place is the pre-out / amp-in jumpers smack dab in the middle of the back of the unit.
touch a wetted finger to each bare metal jumper, one at a time. should get buzz from one speaker when doing this.
To prove the concept works and that your finger is noisy enough.
If your finger is too wide, straighten out a paper clip
(tape up the business end, all but the end of the tip to avoid shorting anything out by touching TWO things at once).
I'm not going to post the picture I'm using for this (unless you ask) , you have successfully navigated the innards of the SX-1080 doing the kit.
If I lose you, speak on up, it's my mistake in not describing it well enough.
After navigating the list I am going to post, we can confirm bad parts by swapping them with good parts borrowed from the working channel temporarily.
Also the list will seem to jump around a bit (binary search?), but we want to get past whole bunches of working circuits quickly. Like the tone amp and filters.
This is all stuff easily accessible with an open bottom of the SX-1080.
Tone control board, where the tone controls are mounted on, near the power switch.
AWG-056 tone control inputs are pin 8 (white wire) for left channel, pin 6 (red?pink? wire) for right channel.
AWG-056 tone control outputs are pin 5 (yellow wire) for left channel, pin 3 (violet wire) for right channel.
touch pin 8, then touch pin 6 hear the buzz? can tone controls affect the buzz when turned on?
if not, touch pin 5, then pin 3 to check that the output of the tone board can buzz.
Now we're going to jump to the volume control board. There are white and red?pink? wires at pins 6 & 8 (again!!) of the GWG-112. They are the opposite ends of the red?pink? (R) and white (L) wires feeding the tone control. Touch them and confirm each hums.
now we are going to find the volume control sliders. And inject hum into them
The red circled pins are the volume control pins, with channel identifiers. One is hidden (just from view) under the face plate bottom.
The circled caps are the next components after the tap, then there is a resistor and then the jfet gate.
touch the red circles to inject hum on the left and right channels.
Last edited:
- Joined
- Mar 6, 2022
- Messages
- 5,566
- Tagline
- music...the healer of souls...
- Joined
- Mar 6, 2022
- Messages
- 5,566
- Tagline
- music...the healer of souls...
good afternoon mark....thanks in advance for your expertise...and time...
going down your list...
i put input on aux with nothing connected...
i have rca cables between preamp and amp in...never had the metal jumpers...
but i did get buzz there when i jumped them underneath without cables
tone board gave buzz on pins 6 and 8 and pins 3 and 5
when i turned the tone bypass to the tone position (not bypassed) ....i heard a slight static out of the left speaker...right speaker silent...
i could tell a little difference in the bass adjustment but hardly detectable on the treble...when i switched tone controls to on...
should there be a lot of difference???
volume board red and white wires both generated buzz
volume sliders were a LOT louder....scared me at first...lol
but was adjustable with the volume control...
how am i doing so far???
going down your list...
i put input on aux with nothing connected...
i have rca cables between preamp and amp in...never had the metal jumpers...
but i did get buzz there when i jumped them underneath without cables
tone board gave buzz on pins 6 and 8 and pins 3 and 5
when i turned the tone bypass to the tone position (not bypassed) ....i heard a slight static out of the left speaker...right speaker silent...
i could tell a little difference in the bass adjustment but hardly detectable on the treble...when i switched tone controls to on...
should there be a lot of difference???
volume board red and white wires both generated buzz
volume sliders were a LOT louder....scared me at first...lol
but was adjustable with the volume control...
how am i doing so far???