Mission cyrus 2 l/h channel low volume

Durro1 · 9th March 2008, 04:51 PM

My beloved cyrus 2 + psx has lost volume on the l/h channel, there seems to be many posts on here regarding this but i end up going in circles. The amp is issue 7 i have removed the circuit board and checked for dry solder joints as i have found some before especially the rca sockets having to endure heavy cables at a funny angle. There seems to be no damage to caps that i can see only the two brick red units that sit under the green ribbon are showing signs of cracking. After viewing various posts and not wanting to replace set up,( i use vinyl just as much as cd ) i have decided either:-
i) To contact cyrus and enqiure about refurbishment, to both 2 + psx- sounds pricey though.
ii) My prefered choice is to do it myself, would like help sourcing quality audio replacement parts, the pots sem fine only the selector switch suffered a few years ago but seems fine after a clean.

richie00boy · 9th March 2008, 05:37 PM

How do you know the pots are fine? Have you traced through the amp with a scope seeing where signals die?

Durro1 · 9th March 2008, 08:00 PM

Hi thanks for the reply, i havn't checked witha scope as idont have one, have only noticed this the past week have done the usual checks, different sources, swapping speaker wires etc. Had the amp apart today to do a visual check, i then decided to join and post the previous request. Since then i have put it back together and found that with no inputs connected i get a huge hum from the good channel when phono selected which only dissapears when i plug the cd players RCA's into the cd input. With one source at a time used the left channel is lacking in volume and bass. It is compensatable using the balance but nowhere near the sound quality.

Durro1 · 9th March 2008, 08:00 PM

Sorry forgot to mention the pots seem fine as there is no noise upon adjustment i think it is more serious than that due to this hum

jaycee · 10th March 2008, 02:48 AM

IIRC the usual culprit is the input coupling cap with this one. Check C33 and C42 (according to the schematic i have!)

9th March 2008, 04:51 PM	#1
Durro1 diyAudio Member Join Date: Mar 2008	Mission cyrus 2 l/h channel low volume My beloved cyrus 2 + psx has lost volume on the l/h channel, there seems to be many posts on here regarding this but i end up going in circles. The amp is issue 7 i have removed the circuit board and checked for dry solder joints as i have found some before especially the rca sockets having to endure heavy cables at a funny angle. There seems to be no damage to caps that i can see only the two brick red units that sit under the green ribbon are showing signs of cracking. After viewing various posts and not wanting to replace set up,( i use vinyl just as much as cd ) i have decided either:- i) To contact cyrus and enqiure about refurbishment, to both 2 + psx- sounds pricey though. ii) My prefered choice is to do it myself, would like help sourcing quality audio replacement parts, the pots sem fine only the selector switch suffered a few years ago but seems fine after a clean.

9th March 2008, 05:37 PM	#2
richie00boy Did it Himself diyAudio Member Join Date: Nov 2003 Location: Gloucestershire, England, UK	How do you know the pots are fine? Have you traced through the amp with a scope seeing where signals die? __________________ www.readresearch.co.uk my website for UK diy audio people - designs, PCBs, kits and more

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9th March 2008, 08:00 PM	#3
Durro1 diyAudio Member Join Date: Mar 2008	Hi thanks for the reply, i havn't checked witha scope as idont have one, have only noticed this the past week have done the usual checks, different sources, swapping speaker wires etc. Had the amp apart today to do a visual check, i then decided to join and post the previous request. Since then i have put it back together and found that with no inputs connected i get a huge hum from the good channel when phono selected which only dissapears when i plug the cd players RCA's into the cd input. With one source at a time used the left channel is lacking in volume and bass. It is compensatable using the balance but nowhere near the sound quality.

10th March 2008, 02:48 AM	#5
jaycee diyAudio Member Join Date: Apr 2004 Location: Norwich, UK	IIRC the usual culprit is the input coupling cap with this one. Check C33 and C42 (according to the schematic i have!)