Problems with CSV 510

Receiver und (Vor-)Verstärker außerhalb atelier/regie/slim line
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Wilhelm
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#31 Beitrag von Wilhelm » 02.02.2011, 16:03

I mean only the electrolytic caps. Yes, bad caps or defective transistors can be the cause. Before you replace C609/709 have them tested, they are pretty expensive. Can you test the output of the pre-amp, oscilloscope would be best?

Wilhelm

If you can, check also the four big emitter-resistors R619/621/719/721 0.22ohm.

skvuppla
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#32 Beitrag von skvuppla » 02.02.2011, 16:35

unfortunately I don't have an oscilloscope only a multimeter.

can I check the emitter-resistors just like I would with a normal resistor?

Is it on sw/rt 084 and sw/ge 085 you test the preamp?

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#33 Beitrag von Wilhelm » 02.02.2011, 16:57

You can check the resistors the same way. Because of the low resistance of .22 Ohms you probably don't get the exact reading with your Multimeter, but a comparision of the four readings should give you a good idea.
084/085 is correct. When you measured the voltages did you disconnect the pre-amp from the power-amp? If not, disconnect and measure again.
Wilhelm

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#34 Beitrag von skvuppla » 02.02.2011, 17:12

now I've measured again, whit power amp unplugged. I get about 13v on 084 and about 14v on 085

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#35 Beitrag von Wilhelm » 02.02.2011, 18:15

....maybe the easier way for you to check the pre-amp is switching the red and yellow wires (left/right) and see whether you get the same signal strength on the good channel of the power amp. If you get the same volume your pre-amp seems to be okay. Make sure that the controls on the front panel are set to the same values for left-right.

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#36 Beitrag von skvuppla » 03.02.2011, 11:13

now I've tried to switch 084 and 085 but it's still the same channel that's not working. So I guess this means it is the power amp that's broken?

On the emitter-resistors I get the same reading on all 0,1ohm


If I replace the capacitors are these good alternatives? (all have the same capacity and voltage as original)

C707/C607 and C702/602 http://dk.rs-online.com/web/search/sear ... &R=6283863

C705/C605 http://dk.rs-online.com/web/search/sear ... &R=5261828

C703/C603 http://dk.rs-online.com/web/search/sear ... &R=6842043

I cant find a suitable replacement for C709/C609 (80v 300uf) :(


Are there more capacitors I should replace?

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#37 Beitrag von Wilhelm » 03.02.2011, 13:50

Good Morning,

your pre-amp seems to be okay. In the long run you might want to replace the caps on this board too, back to the power amp.

Your choice of caps is fine.

For now don't change C609/709.

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#38 Beitrag von skvuppla » 03.02.2011, 17:29

I have replaced the caps, but there's no difference. Still no sound in one channel.

I've noticed that if I turn up the volume to -12db or more the speaker pops or crackles, but still no sound in right channel

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#39 Beitrag von Wilhelm » 03.02.2011, 18:54

...now you have eliminated one source that could have caused the problem. It is time to check the transisitors and the diodes, either by comparing the voltages from the left and right channel or desolder them and check them individual. Because you have only a Multimeter for testing here are two links telling you how to test semiconductors.

http://www.testingelectroniccomponents. ... KgodTRRBBg

http://www.electronics-radio.com/articl ... r-test.php

Regards
WIlhelm

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#40 Beitrag von skvuppla » 07.02.2011, 11:24

I'm pretty sure that at least one of the 2n3055 transistors are broken since it conducts all ways and between all legs and the "shell"

should I replace all of them? and is this a good replacement?
http://uk.rs-online.com/web/search/sear ... &R=4864476

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#41 Beitrag von Wilhelm » 07.02.2011, 14:06

No problem with the the replacement (link). If you are not 100% sure whether the second one is okay, replace it too. What about the driver transistors BD139/140 in front of the 2N3055's? By the way, the "shell" of the 2N3055 is the Kollektor and it must be properly isolated from the heat sink. You can check this with your multimeter. Don't forget the heat sink paste!

You are making good progress.
Regards
Wilhelm

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