1977 Yamaha CR-2020 Vintage Stereo Receiver Repair

If you’re looking for a repair for this particular model of receiver, sorry – Rain City Audio no longer takes Yamaha CR series for repairs due to them requiring such an extreme amount of work. This post is a good resource for techs, though, so it’s still up.

The Yamaha CR-2020 drives 120W/channel into an 8 ohm load and supports 3 pairs of speakers (but only plays 1 or 2 pairs a time), dual phono inputs supporting both moving magnet (MM) and moving coil (MC) pick-ups, tape-copy functionality with a separate output selector, and a variety of tone control and FM Stereo adjustments.

The owner reported the unit was playing, then suddenly went silent and wouldn’t play anymore. Telltale signs of smoke rising from the inside can be seen on the vent slats.

Let’s take a look inside…

An absolutely mammoth transformer, and the two final amplifier modules with enormous heat-sinks. Above the transformer is the power supply section; the far left moving out of the photo is the tuner.

The power supply has had three capacitors replaced but most are original. The lights have been modified at some point as well, although somewhat sloppily.

Yamaha used a drive-shaft type arrangement for the MM/MC switch with two flexible linkages to turn a switch all the way at the rear of the unit from the front panel. The dial arrangement is one long string that wraps around about a half-dozen pulleys. Not only is this a very complex, powerful electrical design it has a lot of physical components as well.

Overall, there’s a lot going on under the hood. It’s time to investigate further.

Here’s a previous repair with a sloppy solder joint visible.

Old and new caps:

It’s generally not recommended to leave old caps in place if some have failed…the others are the same and experienced the conditions, they’re going to go eventually – which is what landed this one back in the shop.

On the underside, the board was badly damaged during the capacitor replacement. It’s tough to repair these old boards without some damage, although that’s a pretty good chunk of foil missing. If a de-soldering iron at too low of a temperature had been used – or a piece of braid – that could have happened pretty easily. All of the joints are pretty cold and looked poorly flowed, though. I re-flowed the ones that looked like it wouldn’t further damage the board with a dollop of new solder.

Underneath the board with the regulator transistors is the rectifier board and massive filter caps.

I see some leakage around the bottom. And there’s evidence of heat from below:

At this point, all the old capacitors in the power supply are candidates for replacement. It’s clear the power supply boards have suffered several failures and need a complete overhaul. There’s quite a few transistors:

More damage. Lifted traces.

The rectifier board with the large filters has quite a few large wires going to it. These are the B+, B- and ground wires for the final boards attached to the rear.

New, computer-grade filter capacitors rated a tiny bit higher than original – all while being slightly smaller.

Nichicon capacitors, some of the highest quality available, were used in this replacement.

Before:

After:

On the left, capacitors which definitely failed – either very high ESR, out of specification, or open circuit. On the right, capacitors which were “technically ok” for now.

There’s a handful of caps on the final boards, too.

It’s time to pull the finals.

From right to left to the power resistor: signal common, signal input, b-, b+,

From left to right: TP1 bias meter point (no wire), amplifier output, ground/CT, B+, B-.

Ah yes, I seem to have found the problem:

Looks like something had a real bad time and let the magic smoke out. It’s destroyed a pair of resistors, a small-signal diode, the HW-21468 fuse resistor, a ceramic disc cap, and a driver transistor – that we know of.

Final output transistors. The amplifier board is held on by the base connections which are screw terminals through these.

The failure was so violent it scorched the board and blew one of the legs off the transistor’s case.

That’s a fair amount of dead parts. Time to hook it all back together and test some more.

Powering back up….nothing. The lights come on, voltages appeared, and nothing caught on fire – but there’s no output. Time to do some probing. Initially, I wasn’t even getting a signal out of the pre-amp stage. There are several places along the way to check for the presence of a signal on the volume gang:

After toggling several switches I did get audio to the inputs, finally. The un-failed channel was doing fine, but the other one, not so much.

The speaker protection relay is checking for proper voltages before connecting the contacts.

Something must be dragging down one of the rails. It turns out one of the sense lines was being shorted to ground; moving some wiring around corrected this problem. The relay clicked and engaged, and perfect sound started coming out – from one channel only. It was pretty clear there were some dead transistors which needed replacing also.

I replaced most of the transistors; unfortunately, the wrong part arrived and when installed caused a major short-out of several components and damaged the board with the spark. This was very unfortunate and is the first time anything of the sort has ever happened. So I tracked down a replacement final board, and refurbished that to install in its place.

This one played great as well. I tested them on my bench speakers for quite a while with the guts spread across my workbench; the bench speakers are very inefficient and this allowed the amp to get a decent work-out. Finally, it was time to get everything back together. I fixed up a bad connection to the dial lights where a resistor lead had broken. Then put it all back together.

Time to adjust the bias! Using the oscilloscope, I measured the voltage between TP0 and the speaker output terminal for a 10mV +/- 1 mV voltage difference.

Finally back in the case, and hooked up to my K-Horns for some real live testing.

The tuner section could stand to be refurbished later on to bring broadcast reception up to standard, but other than that, it sounds fantastic. Warm and rich, it consumes the FLAC audio I use for testing easily and pumps out incredibly crisp, accurate sound with a ton of power and headroom to match. It’s great to have it back in operation. I’m probably going to get myself one of these at some point, it would make a great center for my own vintage hi-fi use.

Due to the extreme amount of labor involved in a full repair on one of these receivers, Rain City Audio no longer takes the Yamaha CR series for service after several proved to be economically unfeasible. Sorry!

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32 Responses to 1977 Yamaha CR-2020 Vintage Stereo Receiver Repair

  1. Bob says:

    I am currently refurbishing my Yamaha CR-1020. I have owned it from original purchase. It sat unused for quite a few years, & I am setting it back up with my Polk Audio M10 speakers. When I set things up, everything played fine. As I used it, sparingly, the right channel began to fail. Oddly, it worked with a different input channel. That is a BIG clue as to the specific problem, I think. Now it has failed for all inputs. So, the problem looks to be prior to the final amplification, I think.

    I am replacing all caps on the main boards, the electrolytic board, the power supply board, & pre circuit board to set a base of good power & input. The 1020 does not have a pre module c board. I am also looking for any obvious issues such as failed parts. After I complete that phase, I will look into other areas such as the tuner area.

  2. Wpg Rolf says:

    Hi, should say the lights remain on but meters are down & of course no sound. I suspect transformer amp? Also inside pretty clean & no burnt resistors. I’m the original owner & cabinet is in top shape.

  3. Wpg Rolf says:

    Hi, my Yamaha Cr-2020 turns on for a moment them you hear a “click” near the power up toggle & off it goes. Any ideas of repair or will it be as intrusive as your video.
    Regards,
    Wpg Rolf

  4. SRT says:

    JWK,

    Thank you so much for this post! How did you end up connecting the screw type filter caps, given that the originals were soldered directly to the board? Did you run wire from the terminals and just soldering the wire to the board?

    • jwk says:

      I think I ran wires to spades, and soldered the spades like the flat terminals of the original caps. It’s been a while since I did this one, though.

  5. Zeon says:

    I’ve a Yamaha CA-800 which has 2 bipolar transistors blown( Toshiba 2sa663, 2sc793). Which ON-SEMI transistors will be proper replacements?

    Thanks

  6. Electone_Guy says:

    There are a couple of failure-prone 2SC458 (one on each final board) transistors that should be changed out. KSC1845 or 2SC1815 work well. Also, make sure you complete the three service bulletins to ensure proper operation. The most important of which would be replacing the two regulator transistors to 2SD525 or TIP41C.

  7. Kathie Corbett says:

    I have an older yamaha stereo receiver that I think I bought in the 70’s or early 80’s. It still works, but the one knob doesn’t stay where you set it. It’s a RX-596 model, black, 173/4 wide, 5″ tall and 13 5/8″ deep. So what do you think? Fixable or not.

  8. Mike says:

    Hi,
    Any idea where I can find a power switch for the CR-2020?

  9. Mike DeLong says:

    My friend has a CR2020 that has been in storage for a number of years. We plugged it in a couple days ago and the left side speaker jacks for speakers “A”, “B”, and “C” work fine but the right speakers do not work at all. I plugged the right speaker into the left jack and it works fine so it is not the speaker. Do you have any ideas where I might start looking to see why the right speaker outputs are not working?

    • jwk says:

      Check with the Pre Out/Main In jacks. Disconnect the coupler and plug the Right Pre Out into the Left Main In and see if you still get a signal from the left channel. If you do, it means that the power amplifier module on that side has an issue. If you do not get sound with Right Pre plugged into Left Main, it means there’s an issue in the pre-amp/tone stack for the right speaker. Check speaker fuses if there are any (I don’t recall). It is unlikely to be the protection relay or the switch if the other channel works. If you don’t have any other test equipment, though, there’s not a whole lot more troubleshooting you’d be able to do. Most likely it’s just come to the end of part of its working life and needs service as shown here.

  10. Michael Gabriel says:

    Hello!
    I have this exact same model Yamaha receiver. It needs to be serviced. How can I contact you?

    Michael Gabriel
    Ojai, CA
    562.212.1779

  11. George says:

    I acquired a couple of functioning amp modules from one of these beasts recently and would like to utilize them in a project. Could you provide some info on the supply voltages that were used in CR2020 to power the amp modules?

    Thanks!

  12. Vic Oilsteems says:

    I’m thinking about picking up a cr 2040 reciever,that the owner says turns on light up but the seems the fm dial string is detached, and is not sure everything works. It obviously will need work and overhauled like this one, do you think it worth it? Are you accepting any work, how much would you charge to do a restoration like one you did on the unit ? Email me with your response.

  13. Greg says:

    I have a similar problem with my CR 2020. It overheated or something because it clipped a couple times and went silent. I was in front of the unit when it happened. All I saw was light and smoke through the top of the vent slats and immediately pulled the plug from the wall. It has been in a repair shop for 20 months due to a lack of parts and circuit boards. With the everything else in perfect shape I wondered if I should part it out?

  14. Walter Czyz says:

    I have the same receiver and would like to know the ball park cost of a repair job like this?

    • jwk says:

      Around $350 in labor, plus the cost of parts. These aren’t especially easy to work on due to their construction, so it’s pretty labor intensive for a full rebuild! I can’t accept these for service outside of the local area unfortunately, they’re just too heavy and large to ship safely.

  15. Bob says:

    I have a yamaha CR2020 which has worked perfectly since purchasing same, but has been used sparingly, and just recently (after being in storage for 2 years) proceeded to use again and I am unable to send a clear signal from the tuner and phono to speakers. Need someone to do an evaluation of the receiver and repair. Located in the Santa Barbara, CA area and would prefer a local to handle this. Thanks, Bob

  16. Mark Shaw says:

    I have this exact receiver since new, it still works and looks like new. All lights including the tuner, work. However, the original speakers need some work. Like the receiver, the speakers are in solid walnut (you do not see quality like that much anymore). The tweeters and midrange are fine. The larger bass speakers need new paper. I am looking for someone who could do this work.

  17. Barry says:

    How much was the charge for this repair: parts and labor? I have a CR-820 that just blew out. Had never been repaired before. Was considering selling.

  18. Frank says:

    I have model CR2040 which I purchase new in 1980. It’s been in storage for over 20 years and recently turned it on. It works great other than some of the lights no longer work. Yamaha no longer carries the lights. Can you suggest where I can get replacements
    gmissinich@gmail.com

  19. Dale Small says:

    I have one of these which I bought new. It recently stopped sound. I was going to send it to recycle unless someone wants it. i live in thousand oaks cal. email dalesmall43@yahoo.com

  20. Very interesting information. It is great to see these old units still in use. Good looking repair job.

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