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<div><span style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);" class="elementToProof">Not nice but unsolder the working DAC, put it to one side and then solder one of the
new ones in the same space to check it works. <br>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> Synth-diy <synth-diy-bounces@synth-diy.org> on behalf of Jean-Pierre Desrochers <jpdesroc@oricom.ca><br>
<b>Sent:</b> 01 December 2023 14:36<br>
<b>To:</b> 'SDIY List' <synth-diy@synth-diy.org><br>
<b>Subject:</b> [sdiy] PCM1702 DAC fakes ? or not ??</font>
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<p class="x_MsoPlainText">I’m working on a Yamaha Clavinova CVP900</p>
<p class="x_MsoPlainText">That has its right channel dead.. no sound.<br>
The left channel is ok.<br>
So, looking at the <b><u>attached PDF file from Yamaha</u></b>,</p>
<p class="x_MsoPlainText">They stated that a common issue was found on PCM1702 DAC’s used<br>
on the main digital board. Noise or no sound at all can be encountered.</p>
<p class="x_MsoPlainText">I checked both DAC and, effectively DAC IC29 had no sound<br>
to its opamp (pin 7 on IC43).</p>
<p class="x_MsoPlainText">The only ‘I thought reliable’ source to buy a PCM1702 I found<br>
was <b>Syntaur USA</b> at $36.95 each.</p>
<p class="x_MsoPlainText">To make sure I ordered two. Ok.</p>
<p class="x_MsoPlainText">So I carefully removed the bad IC29 and soldered a new one.</p>
<p class="x_MsoPlainText">The result ? Now both channels were dead !!</p>
<p class="x_MsoPlainText">I thought I could have done something on the main board<br>
while replacing the bad chip.. So I desoldered it and powered back the unit.</p>
<p class="x_MsoPlainText">The left channel only came back alive… Hmmm…<br>
So I picked the second DAC I had left on hand and soldered it<br>
on the board.. Again both channels dead !!!</p>
<p class="x_MsoPlainText">So 2 things could be happening.</p>
<p class="x_MsoPlainText">New Fake PCM1702 IC’s that load the common data buses (QCLK, WCLK) when installed<br>
and keep the good DAC from working.. ?</p>
<p class="x_MsoPlainText">Or the driving IC that brings QCLK and WCLK to both DAC’s<br>
that is getting weak and drop when 2 DAC’s are installed (That I doubt).<br>
By the way I had no way to check digital waveforms on both DAC’s<br>
beacause they are placed underneath a big daughter board.</p>
<p class="x_MsoPlainText"> </p>
<p class="x_MsoPlainText">So what do you think about that ?</p>
<p class="x_MsoPlainText">Hmmm. </p>
<p class="x_MsoPlainText"><span style=""><img width="816" height="657" id="x_Image_x0020_2" style="width:8.5in; height:6.8437in" data-outlook-trace="F:1|T:1" src="cid:image002.jpg@01DA2439.E56D1CC0"></span></p>
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