Sir Pants
New Member
I picked up this very dusty CR-1000 about a year and a half ago--I knew it was going to be a project but it has become quite the problem child! Enough to force me out of my lurker status to ask for some help!
The story so far: The thing looked like it had a useful life, then sat on a garage shelf for 20 years...an even, undisturbed layer of oxidation and grime everywhere. On first listen, it was working...sort of. There was music, but also very LOUD buzzing through the headphones, from the power supply I assumed. Setting to work, I found lots of bad caps on the PS board. Replaced everything with new Nichicon PW and ES and got rid of a handful of 2sc458s since I had replacements on hand. Should have improved things but post-recap I couldn't even get a relay click. One by one, the big power transistors on the board (2sc1061, 2sa671) started to go bad in the most aggravating way: failing under power but every one of them tested good out of circuit. Shelved the receiver for over a year in frustration while I worked on other projects but I got brave and dragged it out again this week. Stuck in some MJE15031/2Gs and at long last we have a relay click and a stable power supply. Recapped the main amp boards while I was at it (only like 3-4 caps per side) and we have a working amplifier section. What I am hearing so far only makes me more excited to get this classic working and in rotation! All adjustments done, the main amp is dead quiet; some noise in the tone sections but I'll worry about that later--we've got bigger problems. The tuner section is DEAD. No lights, no meters, no sound.
Maybe it has been too long and I am not recalling correctly, but I seem to remember getting FM when I first tested it out? Seems like every time I fix one thing on this unit, another thing breaks...Anyway, I've been poking around the tuner section, checking what voltages I can read from the more legible scans of the service manual I can find, but I could use some helpful advice at this point, a more systematic approach.
What I've found so far: Checking the voltages on the board against the printed values, 12V and 33V are good; MU/MUB (muting I assume) should be 7.4V but read 1.1 and FB (function board?) wants 11.3V but has .336. Traced back to the FM selector switch, gave that whole bank of switches a good cleaning but no difference. I don't really understand where that voltage originates, and where I ought to probe next. Nothing is forming a coherent picture to me yet. Where to start? Any guidance from the Yamaha gurus is appreciated!
Regards,
Pants
The story so far: The thing looked like it had a useful life, then sat on a garage shelf for 20 years...an even, undisturbed layer of oxidation and grime everywhere. On first listen, it was working...sort of. There was music, but also very LOUD buzzing through the headphones, from the power supply I assumed. Setting to work, I found lots of bad caps on the PS board. Replaced everything with new Nichicon PW and ES and got rid of a handful of 2sc458s since I had replacements on hand. Should have improved things but post-recap I couldn't even get a relay click. One by one, the big power transistors on the board (2sc1061, 2sa671) started to go bad in the most aggravating way: failing under power but every one of them tested good out of circuit. Shelved the receiver for over a year in frustration while I worked on other projects but I got brave and dragged it out again this week. Stuck in some MJE15031/2Gs and at long last we have a relay click and a stable power supply. Recapped the main amp boards while I was at it (only like 3-4 caps per side) and we have a working amplifier section. What I am hearing so far only makes me more excited to get this classic working and in rotation! All adjustments done, the main amp is dead quiet; some noise in the tone sections but I'll worry about that later--we've got bigger problems. The tuner section is DEAD. No lights, no meters, no sound.
Maybe it has been too long and I am not recalling correctly, but I seem to remember getting FM when I first tested it out? Seems like every time I fix one thing on this unit, another thing breaks...Anyway, I've been poking around the tuner section, checking what voltages I can read from the more legible scans of the service manual I can find, but I could use some helpful advice at this point, a more systematic approach.
What I've found so far: Checking the voltages on the board against the printed values, 12V and 33V are good; MU/MUB (muting I assume) should be 7.4V but read 1.1 and FB (function board?) wants 11.3V but has .336. Traced back to the FM selector switch, gave that whole bank of switches a good cleaning but no difference. I don't really understand where that voltage originates, and where I ought to probe next. Nothing is forming a coherent picture to me yet. Where to start? Any guidance from the Yamaha gurus is appreciated!
Regards,
Pants
