• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

Yamaha CX1000 phono issue.

Crazeehorse

Crazeehorse

Active Member
I think my CX1000 phono stage needs some TLC. Just curious if anyone has ever had these symptoms with any of their phono stages. My problems started about 2 weeks ago when I noticed that my right channel has loss 3 to 5 db gain compared to my left channel when playing vinyl. Switch to CD or Tuner and no issue at all, ever, and I've played hours and hours of CD's. The problem is intermittent and I thought I isolated it to a problem with my PX2 tonearm, never got around to troubleshooting the PX2, but the minute I put my PX3 into play all problems went away for more than a week. Then last night I noticed the problem again with the PX3 in the mix. After playing side 1 perfect with great imaging and sound quality, I turned the lp over, dropped the needle and bam, right side is down on power. I'm running a LOMC cart and have swapped out that cart for another LOMC cart with the same results. I have a spare CX1000 that is basically a donor so I can recap that phono stage and swap but I would like to find the real culprit in the phono stage that is currently in use. Was just hoping someone would have some words of wisdom on what to test and look for in case they had come across this as well. I wish I had an MM cart to test so I could see if it was just the MC side of the house messing up. The CX1000 and MX1000 have been completely recapped(minus the big 4 on the MX) and refurbished about a year and a half ago. I use it daily for about 2 to 3 hours after work so it and the MX1000 are very much used. Maybe time to go get a new A-S2100 or A-S3000? Just love this old gear though.
 
Register to hide this ad
I would be starting with the bowden-cable linked MC/MM/loading PCB mounted switch on the phono preamp board.

You can remove the entire phono stage PCB easily (screws on the rear panel and two side bracket screws) and give the switch a good clean with a quality contact cleaner. If it (the switch) proves to be intermittent again, the only solution is to remove the switch from the PCB, carefully dismantle and clean all the silver-plated wipers and contacts (tedious).

Popped the cover on my CX1000 to show you:
cx phono.JPG

Be careful if you remove the nylon actuator clips from the top of the switch- they are likely getting brittle (it's 27 years old now)
 
Thank you very much. I have the board out and did remove the switch for a really good cleaning with deoxit. The switch did need cleaning for sure so hope this helps. I recapped my entire cx1000, electrolytics only, about 2 years ago. It has been running like a champ since. Should one consider the poly and mylar caps as well while I got her on the bench? I didnt think these would be in the same boat as the electrolytics. One thing I have noticed was my dc offets were higher than spec, they were 10mv give or take not 2 to 2.5mv per the service manual. I did notice that vr4 or vr5, cant remember I'm at work right now, were very very hard to get adjusted right. Once adjuster to 2.3mv per channel I let her run for an 3 hours to make sure she stayed set. Thanks again.
 
I wouldn't be changing the other smaller caps unless they prove to be causing any issues. Give the phono (MC/MM/Loading) switch plenty of rotations back and forth every now and then to keep the self wiping contacts clean and you likely won't have the problem re-occur.
 
restorer-john said:
I would be starting with the bowden-cable linked MC/MM/loading PCB mounted switch on the phono preamp board.

You can remove the entire phono stage PCB easily (screws on the rear panel and two side bracket screws) and give the switch a good clean with a quality contact cleaner. If it (the switch) proves to be intermittent again, the only solution is to remove the switch from the PCB, carefully dismantle and clean all the silver-plated wipers and contacts (tedious).

Popped the cover on my CX1000 to show you:
View attachment 776728

Be careful if you remove the nylon actuator clips from the top of the switch- they are likely getting brittle (it's 27 years old now)
Click to expand...
:thumbsup:
 
the nylon actuator clip are fragile yes (very old part as said) can you tell us what part number there is on the blue ruban and what part number (ALPS number) do you have on one side of this slide switch ?
 
You must log in or register to reply here.
Back
Top Bottom