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Old 5th July 2012, 02:43 PM   #1561
nar is offline nar
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Oh, problem with those. Should be around 8 - 10 V
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Old 5th July 2012, 02:52 PM   #1562
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Does that mean replacing?
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Old 5th July 2012, 02:52 PM   #1563
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Are you sure value of R5

nAr
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Old 5th July 2012, 03:03 PM   #1564
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Took them out and both say 1.498 k. But then there's R7. I've read here about trouble installing it. I've experienced them too, but ended up soldering it. Seems OK.

EDIT / I have two spares for ZVX450.

Last edited by Siberia; 5th July 2012 at 03:09 PM.
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Old 5th July 2012, 04:14 PM   #1565
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For sure the sub mc regulator has a problem. And the cascode too. It seems a soldering issue to me, check again all solders. Do you have proper R28 & R29 idle values ? those should measure about 1V

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nAr
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Old 5th July 2012, 04:33 PM   #1566
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I was just desoldering Q3, when I fipped and made a picture of the underside, focusing on the section that can cause trouble:

http://i49.tinypic.com/2e5uo2x.jpg

Nevermind those dirty holes in the middle I'll wipe them clean.
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Old 5th July 2012, 05:04 PM   #1567
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Across R28, R29 I read 1.1V. Changing Q3 didn't help. What's the practice, if the solder looks OK, but there surely must be trouble somewhere? Desoldering, soldering action on cascode section?
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Old 5th July 2012, 05:13 PM   #1568
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Have you got the jumper in place of R15 or a resistor?
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Old 5th July 2012, 05:20 PM   #1569
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rahul, I've got jumpers there.
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Old 5th July 2012, 05:45 PM   #1570
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Quote:
Originally Posted by Siberia View Post
I was just desoldering Q3, when I fipped and made a picture of the underside, focusing on the section that can cause trouble:

http://i49.tinypic.com/2e5uo2x.jpg

Nevermind those dirty holes in the middle I'll wipe them clean.
I see a solder plot at the right bottom of the pic, seems to make short between gates and ground plane

otherwise solders look OK.

nAr
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