• 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 CR-1000 help needed

jmascarenhas

jmascarenhas

Member
Hello all and congratiulations for this excelent sharing and learning forum.
I have been following this forum for a long time, and it's my time of needing some help.
I have a Yamaha CR-1000 for a couple of years, along with a revox B780 and a Technics su-V8.
Well,...I lived in a house with high Humidity levels.
All three amps developed some issues probaly due to the humidity.
The Technics is allready in good condition. I have recaped it and had to change a transistor.

The Yamaha CR-1000, was all cleaned, pots, couple switch. Power amps adusted.
The problem, is that the left channel is lower than the right channel. I would say about 30% lower. Not only through speakers but also from phones.
If I turn the Stereo to Mono, the sound is equal on both sides. If I slide the balance to the left in stereo the sound is notouriously lower, but not in mono.
I have changed SK30A transistor from power amp left.
I have removed, measured and reinstalled several caps witchhave been all under specs.
I have not seen any bad weld in any pcbs.
I tried to adust the equalizer amp, but I am not sure what is the TP1 and 2 pin from the schematics. They are not exactly like the physical pcb.
I have been trying to trace the source of the problem but no luck.
I would appretiate any help and thoughts.
I know there are a couple of Gurus of Yamaha Gear, so if they are willing to provide some guidance I would thank them alot.
 
Register to hide this ad
Suggest work though all switches in turn by operating maybe 10 times and note any change (good or bad), that switch will probably need further cleaning. Try "REVerse" mode if it exists on the CR.
 
Last edited by a moderator:
In relation to switches, I have clean them and tried operation individually several times and no change, What do you mean by reverse? Stereo? If so, it restores power to the left channel.
Also, I have measured the input and output in mV in power amps, and INput are the same on both channels (around 9mv), but OUTput is much lower mV in left channel. I believe the problem could be here. I already changed a SK30A transistor (not sure if for a good quality one in terms of brand). The Tuner was playing wile doing theses measures.
 
Last edited by a moderator:
jmascarenhas said:
What do you mean by reverse? Stereo? If so, it restores power to the left channel.
Click to expand...
Little unclear. "Reverse" sends the left channel (RCA) input to the right channel and right channel RCA to left pre/power amp.
If you are seeing both channels normal with reverse selected then you have a switch issue. However your power amp voltage
measurements suggest a power amp issue. Just need you to confirm on reverse behaviour...
 
mbz said:
Little unclear. "Reverse" sends the left channel (RCA) input to the right channel and right channel RCA to left pre/power amp.
If you are seeing both channels normal with reverse selected then you have a switch issue. However your power amp voltage
measurements suggest a power amp issue. Just need you to confirm on reverse behaviour...
Click to expand...
It does not have that function. I thought you were talking about reverse stereo. When I connect stereo to L+R, the volume of left channel equalizes to the right.
 
Welcome aboard..

Have you tried cleaning or messing with the pre-out/main-in coupler switch on the rear Panel ? This switch is notorious for getting filthy..
 
@mbz - When in reverse or Mono sound in left channel equals the right channel.
@avionic - Yes. Cleaned coupler switch and also tried bypass it with rca's. Problem persists.
I believe is something in power amp left board. Just can't find where.
 
Function switching, mode switching or tone controls...Are possibilities.
 
Last edited:
You must log in or register to reply here.
Back
Top Bottom