Faulty Yamaha DSP-A2070 - diyAudio
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Old 22nd May 2012, 09:24 AM   #1
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Default Faulty Yamaha DSP-A2070

One of my friends recently bought an A2070. He was quite impressed listening to mine and got this one from ebay. The seller was the original owner and bought it at 1995, so the amp is 17 years old.

DSP-A2070 Pics

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Now about the problem, suppose if were listening music yesterday in the morning and it performed perfectly. Then we set it to standby mode via remote (the red LED is lit beside the standby button on the amp) and then switched it off from the wall mount AC input.

Next morning after 24 hrs when we again put on the amp we find it is no more in standby mode (the red LED is not lit). Then when we press the standby button on remote a double clicking sound is heard in quick succession and the A2070 starts up, the input selector switch makes a complete round and settles in LD position (it was set to CD while turning off) and the DSP volume setting for the center & effect channels are gone back to default. It is like the memory settings are completely lost.

This problem does not persist if we restart the amp within a short period say 6 to 8 hrs time. Say after 8 hours we switch it on and find it is in standby mode (the red button is lit) and pressing the standby button on remote a double clicking sound is heard in an interval of 5 secs and the input selector switch does not rotate but stays at CD position and the DSP volume setting are also present.

I am a noob so please kindly help!!!

Do we need to replace any battery inside the amp?

Last edited by RishiGuru; 22nd May 2012 at 09:33 AM.
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Old 23rd May 2012, 07:26 AM   #2
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Got the news for another forum that it may e memory related and often was done by a super capacitor as opposed to a battery. Super caps were found on 80s and 90s Yamahas.

We have downloaded the A2070 service manual and here is the link:

http://rapidshare.com/files/31387672..._DSP-A2070.pdf

These are our findings:

The amp was released in 1993 and does have a PCB board that controls the overall functions. Here is the pic of that PCB:

Click the image to open in full size.
This PCB holds an IC which we assume is the CPU and controls the entire amps general functions. (may be wrong) . It is named IC35. Here is a closer pic:

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IC35 is defined in service manual as:

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Just on the upper right corner of IC35 we find a button like cell named C220.

Is this C220 the super capacitor you are taking about?

Here is another pic:

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You can find the tiny black cap on the side of IC35 in the PCB that is lying on the ground.

Closer Image:
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C220 is described as:

1) Part No : VE632800
2) Type: C.EL (Electrolytic Cap)
3) Description: 0.047F, 5.5V

Mind you the value is 0.047F and not 0.047mF. Are both the same? This capacitor has a [M] logo. Digging the net we found M stands for Matsushita Corp of Japan.

Where can we find this cap? Do you believe replacing this might solve the problem?
We both live in India and here we have very limited access to HiFi and there parts. Can you provide some internet links so we can order from it.

Replacing seems easy since we do not need to resolder, just to replace the cap from inside its hinge.

Can you or anybody please help us out? Thanks in advance!!!

Last edited by RishiGuru; 23rd May 2012 at 07:38 AM.
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Old 23rd May 2012, 09:11 AM   #3
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Sounds like you've found the (likely) culprit.

0.047F (a 5.5V type I guess) is not especially large by goldcap standards, you can easily get these with up to 1 F. If you can find a larger-capacity one that physically fits, just use that. Any major electronics parts supplier should have a decent selection of these supercaps.
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Old 23rd May 2012, 01:56 PM   #4
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Quote:
Originally Posted by sgrossklass View Post
Sounds like you've found the (likely) culprit.

0.047F (a 5.5V type I guess) is not especially large by goldcap standards, you can easily get these with up to 1 F. If you can find a larger-capacity one that physically fits, just use that. Any major electronics parts supplier should have a decent selection of these supercaps.
Here is another pic of the button sized super capacitor :

Click the image to open in full size.

sgrossklass i believe 0.047F = 47mF = 47,000uF. What are this caps called? button cell caps?
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Old 1st June 2012, 06:09 PM   #5
jitter is offline jitter  Netherlands
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These are known as supercap or goldcap.
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Old 2nd June 2012, 05:18 AM   #6
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Hi Rishi,

Here's the exact part :

EECF5R5U473 - PANASONIC - CAPACITOR, 0.047F, 5.5V | element14 India

Note down the element14 part number.

Go to Shopping.kitsnspares.com and use the search function (set to element14) and find the part. You can have this thing in your mailbox in two weeks for the price + INR 100 shipping.

Hope this helps.
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Old 2nd June 2012, 06:03 AM   #7
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On a second look, I think EECS0HD473H - PANASONIC - CAPACITOR, 0.047F, 5.5V | element14 India is the drop in replacement. But I don't think you can do it without putting an iron to the board.

(Apologies for the double post, I can't seem to edit my previous post)
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