Worth repairing a CR-2020?

elektronror

Well-Known Member
This is my first post on this forum so i will tell alittle about myself before i go in to the questions.

My name is Fredrik, im 15 years old and i live in Sweden. As everyone else in this forum im intressted in sound but not any sound. For about a year ago i bought my first tube radio, its from 1939 so its quiet old. As i presumed it didnt work and i didnt have much skill to repair it at that time so i just used it as a furniture. Some weeks after that i bought a small Philips 60s radio with tubes and transistors. That did work and after the first song on the radio i was stuck with tubes. So i bought more and more radios and i learned how to fix them.
Ive used all kinds of tube amplifiers to power my Pioneer hpm-40 speakers. All from radios to recordplayers to DIY ive built myself till my dad brought home a nice Tandberg Huldra 10. Took some time to fix it but ive used and i am using it since i love the sound, sounds really really nice. The ''problem'' now though is that ive brought home a Yamaha CR-2020. When i got it home it worked great, played with it for an hour. I was suprised how little bass under 40hz there was and how cold and life less the treble is. I must say that it sounded like crap to my ears. (Sorry to all the Yamaha lovers)

Well, its time for my questions.
Ive read alot about it and it seems like its really good. The bass seems to be a problem that it just has. The real problem is the treble, many say its nice and clear but in my opinon its not. Now, its very hard to say if its good or not by not listning to it so i dont really know what to do with it. Cant listen to it anymore since its broken. The relay wont switch and some other things wont work, i suspect a bad wire or something but i havnt found anything yet.
So my question is, is it worth reparing? Even if i dont i will absolutely not throw it away but it takes space since its quite large.
 
This is my first post on this forum so i will tell alittle about myself before i go in to the questions.

My name is Fredrik, im 15 years old and i live in Sweden. As everyone else in this forum im intressted in sound but not any sound. For about a year ago i bought my first tube radio, its from 1939 so its quiet old. As i presumed it didnt work and i didnt have much skill to repair it at that time so i just used it as a furniture. Some weeks after that i bought a small Philips 60s radio with tubes and transistors. That did work and after the first song on the radio i was stuck with tubes. So i bought more and more radios and i learned how to fix them.
Ive used all kinds of tube amplifiers to power my Pioneer hpm-40 speakers. All from radios to recordplayers to DIY ive built myself till my dad brought home a nice Tandberg Huldra 10. Took some time to fix it but ive used and i am using it since i love the sound, sounds really really nice. The ''problem'' now though is that ive brought home a Yamaha CR-2020. When i got it home it worked great, played with it for an hour. I was suprised how little bass under 40hz there was and how cold and life less the treble is. I must say that it sounded like crap to my ears. (Sorry to all the Yamaha lovers)

Well, its time for my questions.
Ive read alot about it and it seems like its really good. The bass seems to be a problem that it just has. The real problem is the treble, many say its nice and clear but in my opinion its not. Now, its very hard to say if its good or not by not listening to it so i dont really know what to do with it. Cant listen to it anymore since its broken. The relay wont switch and some other things wont work, i suspect a bad wire or something but i havnt found anything yet.
So my question is, is it worth reparing? Even if i dont i will absolutely not throw it away but it takes space since its quite large.

Hi! Welcome! Yes I would restore that Yamaha CR2020, but keep it as cheap as possible. Your ears have discovered the magic in tubes. Now this is only my opinion. But I too own a CR 2020 and it is a very nice solid state receiver. But it will never sound as good to my ears as my Dynaco SCA 35 tube amp. Or of course my big Cat JL-1 amps. So I would fix it up, perform the service bulletins and sell it and use the money to buy a old Dynaco or Scott, etc tube amp to fix and enjoy. Just my opinion. :yes:

Ken
 
Start with the service bulletins, and recap the two boards while you are at it. with the relay you're only looking at about $30 in parts. (over here anyway... Not sure what your sources are there)
That alone might bring the sound back to life.
Check some of the other recent 2020 threads in this section for tips.



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Hi! Welcome! Yes I would restore that Yamaha CR2020, but keep it as cheap as possible. Your ears have discovered the magic in tubes. Now this is only my opinion. But I too own a CR 2020 and it is a very nice solid state receiver. But it will never sound as good to my ears as my Dynaco SCA 35 tube amp. Or of course my big Cat JL-1 amps. So I would fix it up, perform the service bulletins and sell it and use the money to buy a old Dynaco or Scott, etc tube amp to fix and enjoy. Just my opinion. :yes:

Ken

The thing is that i cant sell it. I dont really know if im borrowing it or if its mine so it has to stay where i know i have it incase they want it back.

But lets say i will sell it or use it so i need to make it work.
Now, ive read that all caps and some resistors on the powersupplyboard needs to be changed but they seem to work since it worked for an hour. Ive loosen the powersupplyboard since the Y capacitor started to frie. Was an old ''Rifa'' which are one thing that i always changed (missed it when i opened it the first time) so probably something is not where it should be.
I belive it has to be an earth ground since when i start it the realy wont switch, the FM center tuning is at minus 20-30% and the stereoindicator wont light up.
But one thing that i really must do first is to get the horrible stench out that came from the broken capacitor. Anyone got a tip? Maybe put a fan at the switch for a night and see if it helps?
 
Start with the service bulletins, and recap the two boards while you are at it. with the relay you're only looking at about $30 in parts. (over here anyway... Not sure what your sources are there)
That alone might bring the sound back to life.
Check some of the other recent 2020 threads in this section for tips.



Sent from my GT-I9100 using Tapatalk 2

Parts arent hard to find, maybe the relay but it shouldnt be a problem.
As i said, it is actually not mine (i think) so i dont wanna spend any money if i cant keep it so i want to start finding obvious problems. If i will keep it i will fix everything thats needed but that will time decide.
 
Well the obvious would be the resistors in the service bulletin. They have probably desoldered.


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The thing is that i cant sell it. I dont really know if im borrowing it or if its mine so it has to stay where i know i have it incase they want it back.

But lets say i will sell it or use it so i need to make it work.
Now, ive read that all caps and some resistors on the powersupplyboard needs to be changed but they seem to work since it worked for an hour. Ive loosen the powersupplyboard since the Y capacitor started to frie. Was an old ''Rifa'' which are one thing that i always changed (missed it when i opened it the first time) so probably something is not where it should be.
I belive it has to be an earth ground since when i start it the realy wont switch, the FM center tuning is at minus 20-30% and the stereoindicator wont light up.
But one thing that i really must do first is to get the horrible stench out that came from the broken capacitor. Anyone got a tip? Maybe put a fan at the switch for a night and see if it helps?

Hi,

If you have not done so, download the service manul and service bulletins. If you look at the vertical oriented electrolytic board closely you will probably see loose resistors or scorched PCB in the area around some of the resistors. That board will need to have the service bulletin performed and the transistors on the relay board that have heat sinks replaced. It's all in the bulletins. Note, the heat sinks are electrically hot so never touch them with the amp is on. :D Like I did.... :sigh:

Ken
 
I knew that it had run hot from the black on the boards. I will buy new resistors and try and if i can find the new transistors i will do that aswell. Fingers crossed that it fixed the problem.
 
I have an old tube console radio/turntable my Grandfather bought when he returned from WWII and I wish you were here to fix it for me
First I would clear up the ownership question
I wouldnt want to spent time and money on someone elses receiver unless they will pay you for it
It is worth fixing up and compared to other gear of its era would sound very good
You are in good hands on this forum
Good luck
 
After replacing the two 22 with 33 resistors it now works again. I know they dont match perfectly but i just use them to test with. I will only order the new resistors and if i find the transistors for now.

The ownership is as mentioned very tricky. It belongs to a radiomuseum here where i live and of course since im intressted in old radios im visiting them very often. You could say i work there, i fix radios and things just to help them. The personal doesnt know anything about these things so someone must. I can pretty much borrow anything i like from them but some things they give to me. This is a thing that they dont know what to do with so until they know im keeping it. To be honest its about 90% chans that i will keep it. The problem is that one day alot of nice things can be thrown away so the things i want i borrow home. I see it as my payment. :)

Jpowell1
If u want to fix it urself im sure u could. If u search on something like ''Fix tuberadio'' on google etc. u will find alot of how to repair them. You will be suprised how easy it is. You can email me if u want help.

The heatsinks is like u say electric but from working with radios that can have about 400V they are nothing to me. But even though i need to be carefully so i dont destroy anything or myself.
 
I have now changed most of the caps on the powerboard, there are still a few left but i dont have them at home. Im planning to change all exept the 18000uF since i dont think they need to be replaced.

After ive replaced the caps and cleaned all the buttoms and switches i must say it sounds much better. Still doesnt sound as my Tandberg but it sounds very good. I can probably make it sound better by changing the caps in the preamp and amp but i wont do that until i know its mine.

One thing ive noticed is that if i power it up one channel can be dead. The Vu meter on the dead channel doesnt move but the working is, but that doesnt hapend every time. Sometimes it helps to turn up the volume quite high but thats not good for the speakers. It sometimes helps to ''restart'' it but then the dead/working channel can switch. I think its really strange since i havnt found any obviosly fault. Anyone got a tip what to look for?

I havnt found the replacement transistors here in sweden that the bullentin says but is it some other ''new'' that i can use? Im gonna buy the caps from Farnell so if anyone has a suggestion i would be very grateful.

Ive also got a question on the lamps, what type should i buy? I cant find the voltage or the ampere on them.
 
Has the relay been replaced? As well- have you cleaned the pre-amp switch at the back? They are known to cause issues.
 
The relay is the same since i havnt found any replacement. Gonna check ebay or something. The switch hasnt been cleaned, thanks for reminding me.
 
Thanks but i cant order from them. Need to buy things for $100 since i dont live in US.
If there was more space in the amplifier i could just choose any 12v relay but it will be hard to fit. Im gonna check one more time for a relay here in europe.
 
If you can't find one, pm me... I'll sell you one of mine at cost + shipping. I have a few from mouser.... Will just get more in my next order.

That's a great price at the link from BK though...

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Well, i cant find one in whole europe. Not even Ebay can help me. The only one that i can find is the one that bktheking send a link of but as i said, to expensive. So 4seatPilot, im gonna buy one from you. Take the rest in PM.

The lamps is 12V 60mA i found in the manual so thats not a problem to find.
 
I have now found the replacement transistors - TIP41C that i will order with the rest of the caps. But im wondering if they need heatsinks? I can probably use the ones from the original.
 
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