[DSP-10] 5V at D1-A1

Tue, 14 Oct 2003 20:20:55 -0700

Matthew:

It sounds from your data that things are running.  The Voltages measured on
the other side of R137 - R144 are on the anode of a diode.  This point
should be about two diode-drops above ground (follow through the schematics,
you'll see the one diode, say D109, then the second one at D1 in front of
the 2m band-pass filter).

As Mike indicated, the RF gain steps from the DSP-10 application should
toggle the QA-QH values in the pattern described.  Make sure you can shut
off one or more of the bits (and see something near 0V at QA, for example).
Remember that you won't necessarily see 0V DC at the anode of the 8 diodes.
This is normal.  (You just need to make sure you see 0V at the output of
U107).

Keep up the good work and let the thread know how you're coming along!

73,
	Roger
	ARS KA7EXM

-----Original Message-----
From: [email protected] [mailto:[email protected]]On
Behalf Of Matthew J. Wolf
Sent: Tuesday, October 14, 2003 6:13 PM
To: kd7ts
Cc: [email protected]
Subject: Re: [DSP-10] 5V at D1-A1

The outputs of U107 look good.

When the RF Board is first power QA though QH are high.

Here is what I measure at QA though QH. Also here that I measure at R137
though R144 on the side facing the diodes.

QA  5.019      R137  1.253
QB  5.020      R138   1.185
QC  5.010      R139   1.331
QD  4.860      R140   1.467
QE  5.018      R141    4.938
QF  5.018      R142   4.984
QG  5.018      R143   5.008
QH  5.018      R144   5.018

I'm thinking that I should try different values for R141, R142, R143, R144.

-Matthew

kd7ts wrote:

>If the UHFA program is running, and you have serial
>communications with the DSP-10, then the voltage should
>respond to the RF gain sequence <SHIFT><F-7> or <SHIFT><F-8>
>or the up and down cursor keys.
>
>Here is a table of values for the U107 outputs
>
>    RF Gain QA QB QC QD QE QF QG QH
>       100   0  0  0  5  0  0  0  5 Volts
>       94    0  0  0  5  0  0  5  0
>       88    0  0  0  5  0  5  0  0
>       82    0  0  0  5  5  0  0  0
>       76    0  0  5  0  5  0  0  0
>       70    0  5  0  0  5  0  0  0
>       64    5  0  0  0  5  0  0  0
>
>     These U107 Voltages should be seen if the serial lines
>are working, regardless of what is happening in the PLL
>IC's.
>
>lifted from:
>
>http://www.proaxis.com/~boblark/dig_ser1.htm
>
>Hope this helps
>
>Mike KD7TS
>
>

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