[TechAssist] Pioneer Stereo SX-1010 static and severe popping in speakers [UPDATE]
- From: Gary McCartney <gary@xxxxxxxxxxx>
- To: techassist@xxxxxxxxxxxxx
- Date: Mon, 31 Jan 2005 18:04:38 -0500
Thanks for all the replies on this thread. I have searched the unit for
the "DIFF amps" (5 legged devices) that a few of you mentioned and I
haven't located them. I have, however changed some transistors on the
one channel's amp board. These are not marked with a location number,
but I have included a link to a photo of the board, below. They are
three- 2SA726 transistors. I used 2SA844's instead. I had to order more
of these to replace in the second channel. For now, I have ran the unit
and it appears to have quited down the crackling in the channel I
changed the parts. Will post a final result later if this is the cure.
http://www.number63.ca/amp-board.jpg
My original message:
I have this old Pioneer Stereo from the 70's, model SX-1010 (same one as
I broke the shaft on- from another post to the list).
There is static and intermittant snap, crackle and pop coming out of the
speakers or headphones. Sometimes it is strong enough to kick out the
speaker protection relay. This is very intermittant, sometimes it is
heard in the left channel, sometimes the right, other times, both
channels. Problem occurs whether unit is set to AM, FM, or audio inputs,
and doesn't matter how I set any the switches or pots.
I have: cleaned and lubricated all controls, soldered every board except
for tuner boards, replaced a number of tranistors and open caps in the
power supply. Have removed jumpers between pre-amp out and power amp in,
so that I know it must be in the power amp section or power supply. Have
also grounded pre-amp outs and power amp inputs to eliminate noise.
Can it be the audio output transistors? If so, is it likely that both
channels would be acting up?
I don't have a schematic.
Thanks for any help.
Gary McCartney
McCartney Electronics
Guelph Ontario Canada
Est. 1984
email: gary (at) number63.ca
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