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Old 13th August 2018, 05:09 PM   #201
tonza75 is offline tonza75  Europe
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Do

Last edited by tonza75; 13th August 2018 at 05:37 PM.
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Old 13th August 2018, 05:26 PM   #202
ggetzoff is offline ggetzoff  United States
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Quote:
Originally Posted by pinnocchio View Post
Enjoying music in mine! Hehe

Delightful !

Ciao!
Do
Do,

Me too!

Cheers,

Greg
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Old 15th August 2018, 06:20 PM   #203
sledwards12375 is offline sledwards12375  United States
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Hello All:

I am up to section 8.17.1 , Adjust output MOSFET current close to intended final bias.
Everything has measured fine up to this step. When I apply power, TP4/V- and TP2/V+ read 0.00 volts, and the offset at output is about 0.5 volts. The MOSFETS are not getting warm. I get the same readings on both boards, so I believe parts are installed correctly.

Should I proceed to increase/decrease P1/P2 to turn on MOSFETS?

Steve
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Old 15th August 2018, 06:43 PM   #204
fab is offline fab  Canada
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Hi
If all previous steps measured fine then it is normal to get 0 volts before adjustments if the vgs off of the mosfet are on the high side (red color band for example). Therefore you can proceed to adjust P1/P2 to get output bias while keeping DC offset close to 0 (<50mv until final bias). At final bias you can tweak dc offset to < 5mv once température is stabilized.
Fab
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Old 15th August 2018, 06:56 PM   #205
sledwards12375 is offline sledwards12375  United States
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Thanks Fab. Will post VGS calcs for confirmation soon.
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File Type: jpeg image1.jpeg (661.0 KB, 259 views)
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Old 15th August 2018, 07:07 PM   #206
Project16 is offline Project16  France
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For information on the black pcb I added TP1 => V+ and TP3 => V-.
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Old 15th August 2018, 08:39 PM   #207
sledwards12375 is offline sledwards12375  United States
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fab/Project16:

I have attached my VGS calculations for review. These are fillable PDF forms and may be used by those interested to post their results.

Steve
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File Type: pdf vgs board A.pdf (66.3 KB, 39 views)
File Type: pdf vgs board B.pdf (59.5 KB, 14 views)
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Old 15th August 2018, 09:43 PM   #208
sledwards12375 is offline sledwards12375  United States
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Apparently forms behave differently on iPhone and iMac version of Acrobat. Here are jpg images of my results.
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File Type: jpg vgs board A.jpg (270.3 KB, 228 views)
File Type: jpg vgs board B.jpg (270.0 KB, 216 views)
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Old 16th August 2018, 02:36 AM   #209
fab is offline fab  Canada
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Quote:
Originally Posted by sledwards12375 View Post
Apparently forms behave differently on iPhone and iMac version of Acrobat. Here are jpg images of my results.
You got 100% for your test
Fab
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Old 16th August 2018, 03:13 PM   #210
fab is offline fab  Canada
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Quote:
Originally Posted by sledwards12375 View Post
Thanks Fab. Will post VGS calcs for confirmation soon.
Hi
You have clean assembly, proper positioning and good size heatsink. Your input cap is a little (far) more expensive than the one specified in the BOM...
Fab
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