<div dir="ltr">Yes. Google will give you the gist, but it fails at a nuanced translation. Therefore, I decided I'd give a better translation for the key line !! For ARCHIVAL PURPOSES...you know? <div><br></div><div>:-)</div></div><div class="gmail_extra"><br><div class="gmail_quote">On Tue, Oct 27, 2015 at 7:24 PM, John Foege <span dir="ltr"><<a href="mailto:john.foege@gmail.com" target="_blank">john.foege@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">Solder is a better idea...it's going to handle the current better and also not be overly inductive.</div><div class="HOEnZb"><div class="h5"><div class="gmail_extra"><br><div class="gmail_quote">On Tue, Oct 27, 2015 at 7:22 PM, K1FSY <span dir="ltr"><<a href="mailto:k1fsy@vhfwiki.com" target="_blank">k1fsy@vhfwiki.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">google translate did good for me i got all that out of it when i read<br>
through it the first time. My cracks were in pretty much exactly the<br>
same place as his too.<br>
<br>
I was going to try using shield wires cause i have a mess of them handy<br>
but i said screw it and just added and reflowed the solder.<br>
<span><br>
On 10/27/2015 7:21 PM, John Foege wrote:<br>
> And because Google translate is garbage, I will translate this line,<br>
> because it's the key line:<br>
><br>
> Vermutlich durch unterschiedliche Ausdehnungskoeffizienten zwischen<br>
> Keramik und Kühlkörper treten im Keramiksubstrat feine Risse auf, die<br>
> mit dem Auge nur mühsam zu erkennen sind. Irgendwann führt das dann auch<br>
> zu Unterbrechungen in den aufgedruckten Leiterbahnen, bei mir gleich an<br>
> sechs verschiedenen Stellen.<br>
><br>
> Presumably, fine cracks occur, which are only with great effort visible<br>
> to the naked eye, due to the different thermal coefficient of expansion<br>
> between ceramic and heatsink material. With time, this leads to cracking<br>
> in the printed circuit board traces as well, which in my case, was<br>
> present at six different places.<br>
><br>
> On Tue, Oct 27, 2015 at 7:14 PM, John Foege <<a href="mailto:john.foege@gmail.com" target="_blank">john.foege@gmail.com</a><br>
</span><span>> <mailto:<a href="mailto:john.foege@gmail.com" target="_blank">john.foege@gmail.com</a>>> wrote:<br>
><br>
> Vermutlich durch unterschiedliche Ausdehnungskoeffizienten zwischen<br>
> Keramik und Kühlkörper treten im Keramiksubstrat feine Risse auf,<br>
> die mit dem Auge nur mühsam zu erkennen sind. Irgendwann führt das<br>
> dann auch zu Unterbrechungen in den aufgedruckten Leiterbahnen, bei<br>
> mir gleich an sechs verschiedenen Stellen.<br>
><br>
> This is, indeed, exactly what I had guessed the problem to be when<br>
> talking it over with Bill while you were off the air earlier. I told<br>
> Bill, that in my opinion, most likely it was the repeated thermal<br>
> cycling of heating and cooling that lead to cracks in traces on the<br>
> power module. Looks like I was right !! Really a very common mode of<br>
> failure. If you were a long-keyer, which you are not, I would have<br>
> said de-soldered itself. But knowing that you don't key long, I<br>
> figured cracked traces from thermal cycling.<br>
><br>
> On Tue, Oct 27, 2015 at 6:57 PM, K1FSY <<a href="mailto:k1fsy@vhfwiki.com" target="_blank">k1fsy@vhfwiki.com</a><br>
</span><div><div>> <mailto:<a href="mailto:k1fsy@vhfwiki.com" target="_blank">k1fsy@vhfwiki.com</a>>> wrote:<br>
><br>
> I was having intermittent power output problems with the IC-207H I<br>
> received in trade from K1MAL. Noticed 35w power output on 2<br>
> meters which<br>
> was reduced and then no output. After opening it up and<br>
> desoldering the<br>
> antenna connector to get the board out I did some<br>
> troubleshooting in the<br>
> APC circuit because the internet said it was a common fail point,<br>
> however it shares the same APC circuit for both vhf and uhf and<br>
> the 70cm<br>
> side worked fine. Desoldered the PA module and popped off the<br>
> plastic<br>
> cover as per this page that john will appreciate, and sure<br>
> enough the<br>
> thing had microfractures in the ceramic board. Instead of going<br>
> crazy<br>
> with tiny wires I just added a little solder and reflowed the traces<br>
> that the cracks were running under and buttoned it back up.<br>
> Apparently<br>
> Icom didn't bother putting heatsink compound on the bottom of the<br>
> modules and just screwed them to the board, so eventually they<br>
> heat up<br>
> too much and snap crackle pop.<br>
><br>
> <a href="http://www.dk7in.de/TM733.html" rel="noreferrer" target="_blank">http://www.dk7in.de/TM733.html</a><br>
><br>
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