CR 1020 tune up

My neighbor just gave me a CR 1020 he had no use for. Half of the lights are out and the tuner doesn't work, but the amp section works with no bad noises or pops, no weak side, no dirty pots or switches. Very clean unit overall.

I plan on cleaning, re-lamping, checking the 10mV on both sides, re-stringing the tuner, checking the +-25v and replacing the 22 ohm fusistors and the 10 ohm resisters on the power board, thanks to all here who have posted on these things.

The thing is, it sounds a little muddy for the first hour of listening, and then brightens up. Is there something else I should look at or consider replacing?

Did you hook up and antenna to the antenna posts on the rear panel?

No, it's running on phono, Technics SL Q3 with an AT95e, which is in great shape and was running through my CR 820 yesterday just fine. I think the tuner string on the CR 1020 is loose. You turn the knob but the dial indicator doesn't move. That's a pretty simple fix, it's the muddy sound for the first hour that's got me thinking I may have another issue, like caps and such.

Thanks for replying so fast, Avionic!

The thing is, it sounds a little muddy for the first hour of listening, and then brightens up

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Deoxit will probably clear it up.Decoupler switch on the rear panel.Could also be the protect relay contacts.Check the idle current/ bias adjustment as well.

Thanks avionic, I'll clean the decoupler switch on the back and flush the protect relay.

jansjetta said:

Thanks avionic, I'll clean the decoupler switch on the back and flush the protect relay.

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Deoxit or any contact cleaner won't help relay contacts.Relay contacts get fouled and pitted from arcing and oxidation.Cleaning with chemicals is usually a very short term temporary fix.Best solution is replacement if the contacts are in bad shape.

OK, will do.

I removed the case on the 1020 today. It was pretty clean, but I blew it out anyways. Cleaned and lube'd the tuners per instructions on this site. Took the screw off the pre out switch in back, cleaned the switch with Deoxit and swiped it a few times. Looked at the relay on the amp. board and it looked OK so I left it alone. Cleaned up some old water/pop deposits on the heat sinks and transformer, nothing serious. Thanks guys for all the documentation on this, couldn't have done any of this without your help.

The idle current was off on both channels. Again, followed instructions on this site and adjusted both sides. Then, because I'm a little OCD, checked it two more times. The first time it had drifted a little, the second time it was fine.

The tuner string was broken where the tongue on top of the wood case slides into the chassis. Selected FM and adjusted the tuner manually, works great, listening to the local rock station right now without an antenna. I'll get the tuner string sorted while I restore the case.

Didn't have the resistors needed to replace the fusistors/resistors on the power amp. board, so I'll do that another day. This appears to be a low hour unit, but I will do this in the near future.

The unit is sounding great, the typical Yamaha clear and bright sound right off the bat, no more muddy sound when it first starts up. Thanks again to all on this site who have documented all of their previous work.

The only problem I have left is the lighting. None of the lights work now and I have no voltage at the wires. I may have blown a fuse somewhere, but I have no idea where it is.

As usual, your help would be greatly appreciated!

Nevermind...duh! Checked the schematic here and found out the proper light hook up, we're good and now the lights are bright too!

Congratulations! You will enjoy it for sure.

Back on the table, rocking out tunes. Tune up done as previously mentioned, new lights installed, case refinished and everything put together.

Case refinish was done with two coats of Minwax #225 Red Mahogany, five coats of Formbys Tung Oil finish, and a heavy coat of Howards Feed and Wax. Came out nice and the color matches pretty well with the original stain, since I didn't remove all of the original stain, just blended it. I'm going to give it a day or two for the wax to harden, do a final buff and put the turntable back on top of the receiver, with some protection, of course.





Thanks again to this site, and especially Avionic, for helping me out.

Got it look'n real sharp!!:thmbsp:

Is that an LED in the dial?


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Yes, they are all LEDs. The meters are warm white LEDs so they look original. The dial indicator is a bright blue LED with the green filter removed. I saved all the original lighting parts, so incandescent bulbs could be installed again to return it to stock. I don't know if I'm going to like the blue dial indicator, but we'll try it for a while and see.

Could you detail your LED conversion?


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Sure, and thanks for your interest, 4seatPilot. I got the lights from Ebay. The warm white LEDs came from one source and the blue LED came from another. I read a lot of posts on this forum and figured out, mostly from Merrylanders' posts, the voltages and milliamps the original lights required and then matched them up. The guy I got the warm white LEDs from was real helpful and checked the schematics on the 1020 and made sure I got the lights I needed, then built them for me. They were a little expensive, about 5 bucks a piece, but without his help I would have messed up. The warm whites were 3mm 12VDC LEDs with a plastic collar that held the LED and contained the resistor necessary to convert them to DC. They were nicely made. The collar was slightly smaller than the hole on the meters the original incandescent lamp rubber holders fit into. I cut the original wires at the incandescent lamps, saved the rubber holders, and then used heat shrink tubing over the plastic collars on the LEDs until they friction fit into the meter holes. It took two layers of tubing. These LEDs are 15 ma each vs. the 65 ma (IIRC) originals.

The blue LED was a standard 5mm 12VDC LED, bare, with a transistor soldered on one tail to convert it to 12VDC operation. The collar on the 5mm LED light itself is larger than the diameter of the well the original lamp rests in on the dial indicator, so I dremeled flats on both sides of the LED, perpendicular to the diode, so it fit in the well and positioned the light for best light transfer to the indicator. The original green lamp filter lifts out and I put it with the original rubber meter lamp holders. The 5mm LED is 20 ma.

I've got some bright white 5mm 12VDC LEDs coming. When I go back into the unit again to replace the power amp fusistors and resistors, I'm going to try these on the meters to get a little more light on them. I'll see if I can dremel the LEDs down to fit into the meter hole with a layer of shrink tubing over them to fit. If I'm sick of the blue dial indicator by then I can convert it back to that nice Yamaha green.

Cool! Thanks. I'd like to put together some LED conversions for my Yammies. I don't recall seeing any green filters in my 1020 dial... Hmm.

Great job!

When you take the dial indicator cover/tuner string holder off the top of the dial indicator with the two little phillips screws, the lamp lays in a rectangular well to the rear/inside of the unit. Directly in front of that well on the indicator body is a slot and a little rectangular piece of green plastic should be sitting in it. If it's not there, someone was there before you and removed it. If it's missing, a piece of green plastic gel cover from a stage light, although thinner, should be about the same color, I think. You could cut it to size with scissors and mess with doubling or even tripling it to get the tint right for your indicator. Hobby Lobby has the gel sheets because I used them to restore the lights on the speedometer of my old Volkswagen bug.

Hey jansjetta.

I'm about to embark on a CR-1020 tune. I'd appreciate any info you can forward. I know my way around a soldering iron, but have never really touched stereos. If you found the service manual, I'd appreciate if you could forward. Also, you mentioned you found on AK info about how to tune the DC offset, etc. Maybe this is in the service manual, but I can't seem to find info on basics, like where to put the muti-meter, which little pot to turn, etc.

My CR-1020 sounds pretty fantastic, but the headphone section sounds terrible, I think there is a cap bleeding power in the circuit that drives the output meters, and I probably should replace some caps when I'm in there.

Any tips or links to specifics would be appreciated.

Thanks.

I'm no expert by far. Avionic, Merrylander and others here certainly are. There is no DC offset on the CR-1020, just idle current. I did a lot of reading on Yamaha threads here before I adjusted mine, there are pictures of the adjustment points and everything in different posts here. Search for "Yamaha 1020 idle current". Basically, if I got it right, idle current is adjusted on the two amplifier boards in the center of the unit. IIRC, there is a TP0 with no wires and a TP1 on each board with either a brown or yellow wire, depending on which board you're on. The TPs are on the front end of the boards and next to each other.

Before I adjusted my unit, I played about 3 hours of tapes on it at a medium level, easy listening. Then I zero'ed out or defeated all the adjustments so it was flat neutral, centered the balance, turned the volume completely down, switched to an unused and empty phono input and waited 10 minutes.

I carefully put mini clips on the two TPs of one board and used a non metallic screwdriver on the pot that is on top of the same board and to the rear to adjust the idle current to 10mv. The pot is really sensitive and a little adjustment goes a long way, so take it easy. I played 90 minutes of tape, set up the unit and then checked the adjustments again. For some reason, they were about .3mv high (10.3mv), so I backed them off, played the other side of the tape and went thru the whole process again. This time they were right where I had adjusted them so I called it good. One board came out at 9.9mv, the other at 9.8, that was good enough for me.

Avionic suggested cleaning the pre-amp switch on the back of my unit, so I did that and it helped with the speaker output and clarity, I think. I don't use headphones, but I'd bet there's probably some corrosion in yours (and mine too). If you sprayed some Deoxit in the holes and then inserted and removed your phone jacks a few times, turning them a little while they're seated, before the Deoxit dried out, it would clean them up, but maybe someone with more experience has the definitive answer. You might do a search on that too. Good luck, I hope your unit comes out sounding as nice as mine, it's been playing almost non-stop since I finished it and it seems to sound nicer every day.