[DSP-10] Initial turn on

[Richard Ewing]

Emil,

W7CXQ and recently completed our DSP-10s. We noted some differences and 
with Bob's  help we finished.

Attached is a doc that &CQ wrote which as norted in RED is differnt than 
the QST article.

I hope this helps.

73  de KO7N

At 03:48 PM 2/18/2002 -0800, you wrote:
>Hi All,
>
>Just finished the PCB for my dsp-10 and have seen a few things that puzzle
>me on initial turn on.
>
>I am applying 11 VDC to the unit with the pcb still out of the case.
>
>1. When I first power on the unit only the amber light comes on and it
>draws about 150 mA of current. In this mode both the +10TX and +10RX
>voltages are zero. Pins 1 and 2 of U108 are also both zero in this mode. It
>seems that if I leave the unit powered up like this for a while and then
>cycle the power the red LED comes on along with the amber and both +10TX
>and +10 RX are present at 10 volts. The unit draws 350 mA at this
>point.Also all the Q outputs from U108 are high.
>
>My question is this normal or is there a problem here?
>
>
>2. The voltage readings at the source of Q101 is 1.85 volts (vs .23 in the
>assy manual) and source of Q4 VCO reads 1.35(vs .91)
>
>Are these close enough to continue or is there a problem here?
>
>
>3. The voltage readings are off on U105 and U106. Reading 2.3 volts on U105
>and 3.8 volts on U106. All resistor values look right and there is +10
>coming into F103 and the 3 paralled resistors. Should I relace these?
>Dosn't seem like anything else in the circuit should effect these values
>except the MMIC's.
>
>Any help or comments would be appreaciated.
>
>73
>Emil
>W1GGM/6
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>DSP-10@mailman.qth.net
>http://mailman.qth.net/mailman/listinfo/dsp-10


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