Yamaha CR-600

[Eastham]

Ok so I need another receiver like I need a hole in my head, but I saw this little receiver all sad and lonely so I "Reluctantly" Bought it.

Very dirty faceplate and knobs, scratchy controls, all lamps burnt out and just unloved in general. Poor thing...



So I removed the wodden case and gave all the pot's a good bath with some Servisol Super 10, great alternative to Caig DeOxit if you live in Europe like me.


Ick, so dirty..



Next I removed the face plate, six screws on top and three on the bottom. All the knobs came off very easily apart from the Balance knob, Just had to be difficult didn't it... Look at all that crud on the face plate, wonder what that is.. Tea? Coffee? Human slime? Nah, just had to be some kind of glue... Just for me...



Note: These flip switches are really easy to get off if you have something like an Isesamo. Just squeeze it in behind the plastic switch and carefully prize it off.



Insides all cleaned out and looking spiffy.



Now how I cleaned the faceplate was a little controversial. I tried everything to get the glue off but it was having none of it, so I used a hot wet scouring pad with plenty of dish soap and gently ran it along the face plate going with the grain of the brush marks, it took a while and I was terrified of rubbing the lettering off but eventually it was clean and well. The results speak for themselfves. *I don't reccomend you use this method unless you have nothing to loose, there is a risk you could damage the lettering.*



Replaced the lamps and put the face plate back on, getting the DC offset and Idling current adjusted. Those trimmers where sensative as all heck! turns out the idling current was at 4mV left and 13mV right, wonder how it got that bad, no wonder it sounded like dookie. Anywho adjusted for 23mV now.



Cabinet oiled and polished and in general looking very nice.


This one's definetely a keeper.

You can probably expect a re-cap in the near future. Thanks for reading.

Higher quality image:

 

[jbailey930]

well done, sir. Tag this post for future reference.

 

[Raynald]

Great save, found a clean one for friend several years ago, it is a daily driver in their kitchen system. Very nice little receiver.

 

[elcoholic]

Nice save. I miss mine.

 

[Eastham]

Thanks guy's. Not quite sure what I'm going to use it for but the tuner is amazingly sensitive. So it might see service in the living room with a nice pair of bookshelvs for radio listening, plus it would look pretty nice in the living room too.

 

[Eastham]

Just hooked it upto my 'scope and tested the output. 40watts on both channels at 1KHz with an 8ohm load. Not bad considering it's rated at 30.

*Edit* I was listening to the radio at 96.7FM (Radio City 96.7) and I noticed it wasn't actually radio city, I turned the dial far left and noticed it wasn't going past 88 and it was going to far past 108, somehow the dail pointer had become misaligned so I lifted the taps holing the dail cord to the poointer, removed the glue and recentered the dail pointer, bent the taps back down to hold the wire, now all the stations are coming in correctly. Strange how it became misaligned with the glue still on the dail cord. anyone got any theories how that happned? Could it have been misaligned from factory?

 

[Eastham]

Another update. A few day's ago it developed a hum and with the help of Petehal and ILikeMusic, it was quickly fixed, a bad solder joint on one of the bridge rectifiers so to anyone who owns a CR-600 I'd suggest you check the solder joint's on the power supply.

I'd also like to mention how you access the power supply and EQ board. First disconnect the connector that goes to the AM antenna board and the little yellow cable that goes to the tuning capacitor, then remove the power switch, it's held on by four clips, on the sides of the receiver you should see a pair of red screws on either side, remove them and loosten the two silver screws inside the slot *Don't Remove the silver screws!* The whole front sub chassis should pull forward and rotate upward's giving you access to the power supply and EQ board. (See pictures)



The rear is also very similar, there is one red screw on either side of the rear panel, remove those and then loosen the silver screws, then there are two black screws on the bottom of the rear panel, remove them and it should pull upwards and fold down. This will give you better access to the output transistors and the am board. (See pictures)



Another problem I cam accross with my CR-600 was unstable bias, found that out when I damn near burned my hand on the top vent. Turns out after adjusting it it had somehow found it's way to 140mV, the old trimmer pot's where dirty and corroded, so I replaced the Idle current adjustment pot's and the DC offset adjustment pot's with a set of 4.7K Bourns 3386 side adjust trimmer resistors. This did require me to remove the output transistors due to the overall wierd design of this receiver. I also went ahead and re soldered the protection relay.



Welp that's all for this update folks! Stay tuned for the recap of the power supply board.

 

[Oldsansui441]

Nice work, it looks terrific now and should serve you well for a long time, another nice piece saved .

 

[Johnno_Oz]

Beautiful job.

 

[BilboBaggins]

Thanks for this thread! I got a CR-600 about 4 weeks ago and tagging this thread for future reference as well. I was lucky and only had to deal with tar and nicotine. The cabinet is near perfect as is the face plate.

 

[Eastham]

Thanks for this thread! I got a CR-600 about 4 weeks ago and tagging this thread for future reference as well. I was lucky and only had to deal with tar and nicotine. The cabinet is near perfect as is the face plate.

Nice. I find that tar and nicotine sometimes act's as a preservative for a faceplate's finish. I've had two receivers in the past that had almost yellow faceplates and after cleaning, they came out almost like a mirror!

 

[BilboBaggins]

Tar and nicotine saved me a lot of money on some McIntosh gear about 4 years ago. The seller had inherited the gear from his uncle, who, apparently, was quite a heavy smoker. They looked so bad when I got them, and cleaned up so well I actually felt guilty about the amount I gave the seller. Later on, I fixed his mc2505 no charge. Felt much better afterwards.

However, I would never buy a computer from a heavy smoker. It just isn't worth it as the fan pulls or pushes the smoke all over the internals! Yech!

 

[Eastham]

Tar and nicotine saved me a lot of money on some McIntosh gear about 4 years ago. The seller had inherited the gear from his uncle, who, apparently, was quite a heavy smoker. They looked so bad when I got them, and cleaned up so well I actually felt guilty about the amount I gave the seller. Later on, I fixed his mc2505 no charge. Felt much better afterwards.

However, I would never buy a computer from a heavy smoker. It just isn't worth it as the fan pulls or pushes the smoke all over the internals! Yech!

Tell me about it, I'm an I.T Tech and some of the worst if not all the worst computers come from heavy smokers, brown dust and semi sticky residue everywhere! I definetely wear PPE with those systems... Laptops aren't as bad, they're just nasty on the outside.

 

[BilboBaggins]

Tell me about it, I'm an I.T Tech and some of the worst if not all the worst computers come from heavy smokers, brown dust and semi sticky residue everywhere! I definetely wear PPE with those systems... Laptops aren't as bad, they're just nasty on the outside.

I used to be, and after I stopped hands on, I started restoring mac computers to fill up my spare time. Became quite good at it with my own os builds for different models. I had even optimized the iMac G3 to run a special build I created for better speed on 10.4. I bought one from a guy that worked lived and smoked with his powermac G4, and when I opened it up to clean it, it was gross! Ended up being the only mac I couldn't restore. Didn't even use any of its parts!

 

[Eastham]

I used to be, and after I stopped hands on, I started restoring mac computers to fill up my spare time. Became quite good at it with my own os builds for different models. I had even optimized the iMac G3 to run a special build I created for better speed on 10.4. I bought one from a guy that worked lived and smoked with his powermac G4, and when I opened it up to clean it, it was gross! Ended up being the only mac I couldn't restore. Didn't even use any of its parts!

I was once given a old Pentium 3 Packard Bell that was owned by a heavy smoker, I took the power supply and cmos battery out, threw it in the shower with plenty of disinfectant and dish soap and went to town with a scrubbing brush and hot water, before it's PCI solts where yellow and by the time I'd finished they where white again, let it dry threw a fresh cmos battery in it and a "new" old but working power supply in it (The original one was dead and I couldn't be bothered replacing the blown caps in it.) And it worked flawlessly and smelled like freshly washed dishes! I think I still have it somewhere.

 

[Eastham]

Another update. Power supply recapped, new filter cap's installed and universal bridge rectifier replaced. Filter caps have been upped to 6,800µF 63v mostly so the diameter fits the clamps, even still the new caps are much shorter than the originals, amazing how far we've come in cap technology. The original filter caps checked at 4,000µF and 3,800µF so they where due for replacement, originally they where 4,700µF 50v. Bridge rectifier was changed because the original 5B-2 was getting weak. Considering replacing the protection relay, seems to be making intermittent contact even after being resoldered, if I do I'll probably re-cap the amp board and the rest of the unit.

 

[Oldsansui441]

Another update. Power supply recapped, new filter cap's installed and universal bridge rectifier replaced. Filter caps have been upped to 6,800µF 63v mostly so the diameter fits the clamps, even still the new caps are much shorter than the originals, amazing how far we've come in cap technology. The original filter caps checked at 4,000µF and 3,800µF so they where due for replacement, originally they where 4,700µF 50v. Bridge rectifier was changed because the original 5B-2 was getting weak. Considering replacing the protection relay, seems to be making intermittent contact even after being resoldered, if I do I'll probably re-cap the amp board and the rest of the unit.

Looking good, nice work. How do you mean the bridge rectifier was "getting weak", did it not pass a diode test without leakage?

 

[Eastham]

Looking good, nice work. How do you mean the bridge rectifier was "getting weak", did it not pass a diode test without leakage?

Thanks. Yeah it was bad, had continuity from AC to DC and showed little voltage one way and 350mV the other. Never seen a diode act like that before. And any reminents of hum are gone now. Plus I think the new 25A 800v Rectifier is a lot more suited (Overkill) for the extra inrush current the new filter caps will be causing.

 

[Oldsansui441]

Thanks. Yeah it was bad, had continuity from AC to DC and showed little voltage one way and 350mV the other. Never seen a diode act like that before. And any reminents of hum are gone now. Plus I think the new 25A 800v Rectifier is a lot more suited (Overkill) for the extra inrush current the new filter caps will be causing.

Ahh fair enough. Sounds like it is all coming together then, will be interesting to hear your opinion on the sound after your repairs/recap.

 

[Eastham]

Certainly is! As for now this receiver sounds very detailed and flat, pretty nice low bass and level mid's and highs, very controlled, sound's a little grainy but just as detailed as my Technics SU-V505 but not as clean sounding, definetely got a "warmth" to the sound. Mellow is how I'd describe it. Very nice mellow receiver if you just want to chill and enjoy the music, with looks that could kill.