The past weeks I spent quite some spare hours in the insides of this Yamaha CR-450. The machine was put into storage some years ago with a blown left channel.
Because of other priorities I forgot about it until I was clearing out my garage en saw it again. What to do: get rid of it or... try and fix it. I must have read hundreds of articles here on Audiokarma and watched many videos.
I decided to just jump in and give it a try. I learned, made some mistakes and was able to fix those. The efforts have paid off; the result is a working machine.
About this CR450: I once bought it thru an auction site, it was working fine then. The only flaws were the power switch that was not original allowing you to twist the knob around, the tuning dial went the wrong way: turn knob right - pointer goes left et vice versa.
Before that I had a black CR420 which I sold and regretted it afterwards. So the 450 showed up. I thought the 420 looked better but the 450 was newer (higher number) while still looking classic: that is not so because the 450 is older. And now I like the 450 better, it looks simpler and cleaner; just a personal thing.
Things I did: there was a capacitor bulging, a resistor burned; replaced those. Someone had been busy in this receiver before and replaced some capacitors and some transistors. I replaced many capacitors and many transistors; some tested not ok. Re-looped the tuning dial cord so the dial moves logically now. this must have been the easiest job and the most rewarding one.
Lessons learned:
For completeness I ordered a recap kit which I will not do again. It took forever to arrive and some capacitors were missing while from other items there were to much of.
This one is obvious for most: Never clean the circuitboard with contact cleaner! (it leaves a white mess; you told me so. cleaning up took a long time)
It is very easy to get lifted traces especially when wick-desoldering transitors. Still trying to get the hang of it. Do often - practise makes perfect.
Measure components before you get them in (some new resistors were bad)
Finally only one channel was working, just like before. How on earth... and the I just used some deoxit on the balance pot in a "what the heck" moment. Voila! Two working channels.
There is still more to do for which I may ask for help. But for now it plays the stars from the sky.
Thanks to everyone here on audiokarma!
Because of other priorities I forgot about it until I was clearing out my garage en saw it again. What to do: get rid of it or... try and fix it. I must have read hundreds of articles here on Audiokarma and watched many videos.
I decided to just jump in and give it a try. I learned, made some mistakes and was able to fix those. The efforts have paid off; the result is a working machine.
About this CR450: I once bought it thru an auction site, it was working fine then. The only flaws were the power switch that was not original allowing you to twist the knob around, the tuning dial went the wrong way: turn knob right - pointer goes left et vice versa.
Before that I had a black CR420 which I sold and regretted it afterwards. So the 450 showed up. I thought the 420 looked better but the 450 was newer (higher number) while still looking classic: that is not so because the 450 is older. And now I like the 450 better, it looks simpler and cleaner; just a personal thing.
Things I did: there was a capacitor bulging, a resistor burned; replaced those. Someone had been busy in this receiver before and replaced some capacitors and some transistors. I replaced many capacitors and many transistors; some tested not ok. Re-looped the tuning dial cord so the dial moves logically now. this must have been the easiest job and the most rewarding one.
Lessons learned:
For completeness I ordered a recap kit which I will not do again. It took forever to arrive and some capacitors were missing while from other items there were to much of.
This one is obvious for most: Never clean the circuitboard with contact cleaner! (it leaves a white mess; you told me so. cleaning up took a long time)
It is very easy to get lifted traces especially when wick-desoldering transitors. Still trying to get the hang of it. Do often - practise makes perfect.
Measure components before you get them in (some new resistors were bad)
Finally only one channel was working, just like before. How on earth... and the I just used some deoxit on the balance pot in a "what the heck" moment. Voila! Two working channels.
There is still more to do for which I may ask for help. But for now it plays the stars from the sky.
Thanks to everyone here on audiokarma!
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