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Old 3rd August 2012, 08:04 PM   #711
Salas is offline Salas  Greece
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For the top halve of each totem pole only.
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Old 3rd August 2012, 08:08 PM   #712
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Thanks Salas
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Old 4th August 2012, 07:10 PM   #713
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Can I measure heater elevated 150V without valves connected or is necessary have the valves connected?
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Old 4th August 2012, 07:48 PM   #714
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It's ok to power up without valves, but the b+ might be higher due to no load.
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Old 4th August 2012, 07:51 PM   #715
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B+ is 300V, but without valves when measuring heater elevated DMM reads 0V instead 150V, heaters are ok 6,1V
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Old 4th August 2012, 07:58 PM   #716
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Check the voltage divider resistors and cap that give you the 150v - something not right there I'd say.
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Old 4th August 2012, 08:10 PM   #717
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ok thks Fran
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Old 4th August 2012, 09:02 PM   #718
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Are you sure Frank? without valves?
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Old 4th August 2012, 09:17 PM   #719
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You should be able to power it all up with no valves installed, just your voltages may be a little higher because there is no load. You won;t be able to check voltages throughout the circuit since you won't have a complete circuit. But you will be able to see your heater and B+ voltages OK.

********Please note that because you have no load, the B+ may take a lot longer to drop to safe levels than normal!!!*********

So you have a B+ of 300V, you have the 2 sets of heaters giving you ~6V. Thats all good.

Now with the power off, check resistance from ground to either side of the 2 resistors that give you the 150V (the 470K-220K in the original heater sch). It seems to me that its likely theres something wrong the the 2 resistors here, or else the connection from the heater to that point?

If it was working correctly, powered up but no valves, you should have:

GND to B+ of 300V
GND to GND of elevated heater of ~150V
GND to + of elevated heater of ~156V
GND to GND of other heater of 0V


Fran
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Old 4th August 2012, 09:23 PM   #720
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I'm doing somwthing wrong, surely I'm tyred, tomorrow I will check again, thanks Frank for support.

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