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Old 8th May 2010, 02:28 PM   #1601
Salas is online now Salas  Greece
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Quote:
Originally Posted by housing View Post
Iset=33R, old used part in the bin box.
Leave it there then, not that critical a position, and hey, has golden legs. Gold is back.
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Old 8th May 2010, 02:33 PM   #1602
housing is offline housing  Hong Kong
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Quote:
Originally Posted by Salas View Post
Leave it there then, not that critical a position, and hey, has golden legs. Gold is back.
Yes, that's an RMG, not RMA.
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Old 8th May 2010, 02:34 PM   #1603
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Very nice build.

Where did you secure the HV shunt board?

Did you try the Quanghao's HV board? (Sorry if I missed this)

Thanks

Bob
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Old 8th May 2010, 02:35 PM   #1604
Salas is online now Salas  Greece
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Quote:
Originally Posted by housing View Post
Yes, that's an RMG, not RMA.
Good thing is that the production HV board works OK then? No problems? You must be the first fully testing it and presenting a photo here, yes?
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Old 8th May 2010, 02:44 PM   #1605
housing is offline housing  Hong Kong
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Originally Posted by flocchini View Post
Very nice build.

Where did you secure the HV shunt board?

Did you try the Quanghao's HV board? (Sorry if I missed this)

Thanks

Bob
Hi Bob,

I didn't order quanghao's original HV board but ordered his Salas shunt HV board right from the beginning.

Thanks,

housing
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Old 8th May 2010, 02:51 PM   #1606
housing is offline housing  Hong Kong
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Originally Posted by Salas View Post
Good thing is that the production HV board works OK then? No problems? You must be the first fully testing it and presenting a photo here, yes?
I think it's perfect. I will hook it up to an oscilloscope soon.
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Old 8th May 2010, 03:31 PM   #1607
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Salas,

I still do not manage to bring the voltages more than 5.2 V for the positive and 5.1 V for the negatives. I think that my leds have a ref voltages too high. Could it be ? Which one can I try to replace to make a test ?

Thanks,

Davide
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Old 8th May 2010, 03:43 PM   #1608
Salas is online now Salas  Greece
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This sounds like a low voltage reg question I suppose. Check output Mosfet's VGS at you max. If its not circa 4V, then your current is robbed by the TL431s and you need even lower Rset as I have learned reading this thread. If it is alone it works anyway. What value of resistor you got as Rset now?
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Old 8th May 2010, 04:05 PM   #1609
housing is offline housing  Hong Kong
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Originally Posted by Nikon1975 View Post
Salas,

I still do not manage to bring the voltages more than 5.2 V for the positive and 5.1 V for the negatives. I think that my leds have a ref voltages too high. Could it be ? Which one can I try to replace to make a test ?

Thanks,

Davide
My measurements may be of help to you:

All LED's sag about 1.91volt - 1.92 volt each
All 2SK170BL's Idss = about 6.5mA
AC voltage in = 10 volt by multimeter

Use 24R 1W for +ve and -ve rail of analogue supply, voltage easily adjusted to 5.6 volt and doesn't sag with load.
Positive rail voltage across 24R=2.104 volt, CCS is about 87.7 mA
Negative rail voltage across 24R=2.056 volt, CCS is about 85.7 mA. So I add a 1K in parallel with the 24R to make the CCS more like 87.7 mA

Use 2x24R in parallel for the +5V digital supply, voltage easily adjusted to 5.6 volt without load (at 166.6 mA output already) but sags to 5.32 volts with load.
Voltage across 12R = 1.999 volts, CCS is about 166.6 mA

All voltage measurement after TL431 for the IC's consumption are fine and about 5 Volt.

Last edited by housing; 8th May 2010 at 04:10 PM.
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Old 8th May 2010, 04:27 PM   #1610
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The +5V alone branch can be challenged for even more CCS setting I have gathered. What is its output Mosfet's VGS when feeding the DAC?
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