Two big problems with my Yamaha CR-2040

[avionic]

TR901 and TR902: KSA992fbu -----OK

TR903: KSC1845fta--------OK

TR904: Mje344g-------- KSC2690AY more current,better gain and faster than 344

TR905: Mje350----------KSA1220AY more current,better gain and faster than 350

TR915: TIP41C--------OK

 

[avionic]

New lamps shouldn't be to hard to find substitutes.

DGWOJO.COM --Dave will build you a Kit for the 2040..:thmbsp:

 

[Lelle]

Nice, thanks :thmbsp:

 

[Lelle]

I was just about to order the parts, I was a little shocked when I noticed the shipping cost. Around $38 dollars converted from swedish currency. The cheapest shipping, was $38, which I think is a bit expensive. But I guess I have no other choice. The other shipping method is more expensive.

 

[clinic-audio]

I forgot to mention D905, but they are the same as D903/904/906 according to the parts list.

But a few things confuses me, many Ref.No in the parts list is empty.

I'll post an image from the parts list. I've put an red "?" beside the empty boxes.

http://audiokarma.org/forums/attachment.php?attachmentid=443735&stc=1&d=1374506484

And will this work fine?

TR901 and TR902: KSA992fbu

TR903: KSC1845fta

TR904: Mje344g

TR905: Mje350

TR915: TIP41C

You mentioned some of the transistors earlier, but will this work fine?

Hello Lelle

You don't know how to read your parts list . As AVIONIC told you they are the same . (sorry if I answer you now but I am not in USA and there is some difference of time between you and me)

But let me precise you another important detail / your scan is good but too short ...What is written in the right colume (we can't see it because you cut it when you scaned it) ?
I am sure there is a sign (I don't know the English name) and the word " INTERCHANGEABLE "

So as AVIONIC told you they are the same ! :thmbsp:

 

[Lelle]

mr_light gave me the parts list for the cr-2040.
I'm going to order the parts that avionic recommended.
I didn't really like the shipping cost, but I want to resurrect my CR-2040.
I won't give up, I've heard from other CR-2040 owners, that the CR-2040's sounds very good and powerful. I love vintage audio, well built, often powerful and sounds awesome.

 

[Lelle]

I've finally got my payment, so I could order the parts from mouser.
The parts arrived today, fast shipping.

The only thing I hated was the shipping cost that was a bit expensive.

I've ordered a bunch of each component, so I have some extra parts if somethings goes wrong.

I'm a bit nervous, but I hope that the receiver will work again.

Do you think I will be satisfied with the power and the sound of this beast?
I have pretty large speakers, so it wouldn't be a problem.

I will tell you the status after the repair.

 

[fredcohiba]

I have a 2040 and it sings....with all original parts. Yours will be like Pavorotti is in the room with you.

 

[Lelle]

Well, good news everyone. I've replaced TR915, TR905 and TR904. And it powers on now and sounds very good. No hum, distortion or noise either. The power amps get quite hot, but that's normal, isn't it?

 

[avionic]

Well, good news everyone. I've replaced TR915, TR905 and TR904. And it powers on now and sounds very good. No hum, distortion or noise either. The power amps get quite hot, but that's normal, isn't it?

Recheck your bias(idle current). How hot is "runs hot" They should run warm to the touch of the heatsinks at idle. Are your speakers less than 8Ω ?Are you pushing it hard?

 

[Lelle]

I'm not pushing it hard, and I'm testing with small speakers atm with average volume. The speaker are at 3.7 ohms. I've measured the ohms. I will try to carefully adjust the bias. I've touched the heatsinks, it felt like around 45 to +50 degrees celsius. Or around 116 degrees Fahrenheit.

 

[avionic]

The speaker are at 3.7 ohms.

That could have something to do with the heat.

 

[Lelle]

I takes around 20 minutes for it to heat up. Maybe the receiver is a bit picky about the speakers impedance. For one pair of speakers, it is rated for speakers between 4 to 16 ohms. But 3.7 ohms shouldn't be a problem. It's 0.3 ohms lower than 4 ohms. Can that make a small difference on the power amps temperature?

I only have one pair of speakers connected.

I will try with some other speakers, and see if there will be any difference with the power amps temp. I'll do that tomorrow, it's 11.33 pm now where i live. I don't want to disturb the neighbours.

 

[Lelle]

I've now tried with 8 ohm speakers, but it still gets very warm. Just like it did with my 3.7 ohm speakers.

 

[avionic]

I've now tried with 8 ohm speakers, but it still gets very warm. Just like it did with my 3.7 ohm speakers.

If the idle current is adjusted correctly then I wouldn't lose any sleep over it.

 

[Baron K Rool]

Try running it without speakers connected. 50C at idle is normal for a class A amp (which this isn't).

 

[Lelle]

I will leave the receiver in idle without speakers, for around 30 minutes. And see what happens.

 

[Lelle]

I left it on idle for about one hour, it is a bit warm, but not as warm when it had signal and speakers connected. I adjusted the bias a little bit, and it doesn't get very warm now. The -55 and the +55 volts are read about 64 volts. Isn't that a bit high? The -60 and +60 volts are at 58.5.
TR915, TR904 and TR905 are very hot,
I have mounted TR915, TR904 and TR905 on the chassis, so it acts like a heat sink. They get very hot.
You can see that In the picture I've uploaded.

TR915: TIP41C
TR904: KSC2690AYS
TR905: KSA1220AYS

 

[clinic-audio]

Hello

The -55 and the +55 volts are read about 64 volts. Isn't that a bit high? !! yes really too much !
There is something wrong again .

TR915, TR904 and TR905 are very hot,
I have mounted TR915, TR904 and TR905 on the chassis, so it acts like a heat sink. They get very hot.

This is a good idea to use the chassis as heatsink but what you described is not normal at all ! when I refixed CR2040 a long long time ago I don't remind me that these transistors goes so hot . There is something wrong , sorry I don't have a CR2040 service manual here ...I will see what is possible to say in the next 24/48 hours !
:scratch2:

 

[avionic]

I left it on idle for about one hour, it is a bit warm, but not as warm when it had signal and speakers connected. I adjusted the bias a little bit, and it doesn't get very warm now. The -55 and the +55 volts are read about 64 volts. Isn't that a bit high? The -60 and +60 volts are at 58.5.
TR915, TR904 and TR905 are very hot,
I have mounted TR915, TR904 and TR905 on the chassis, so it acts like a heat sink. They get very hot.
You can see that In the picture I've uploaded.

TR915: TIP41C
TR904: KSC2690AYS
TR905: KSA1220AYS

Does this unit have a multi-voltage selector ?