[DSP-10] Initial turn on

[Lee Scott]

Having just finished my DSP-10, I ran into the same problem.  I ignored the 
measurements due to the fact I could not get +10R until I attached the DSP 
Processor and LapTop.  Once everything was attached, it worked fine.  I 
think those measurements are somewhat invalid as I see no way to have the 
74HC595's come up properly in the receive mode until the processor 
initializes them.

Another problem I ran into is the 10Mhz Osc is 10KHz too high in freq (I'll 
pad C109 with a 5pf chip) and the 124mhz LO wouldn't oscillate any higher 
than 110MHZ in it's free running state.  Am waiting for a few chip caps to 
fix those problems.  I was able to get the LO to oscillate high enough for 
the PLL to lock  by temporarily removing 2 windings from L103 and removing 
the slug from L102 but never made it up to 147mhz.  I figure I have to set 
the chip caps C117 and C118 to about 2/3 of their value.

I made a few other mods such as a new cabinet which is a little larger and 
on the front panel, I placed a red led for xmit, green led for receive, a 
yellow led for FL1 which I brought out from the DSP and a red led for pwr. 
I'm also thinking about an led bar meter for power output monitor on the 
front and just as I was contemplating that, there is an article in this 
months QST for one on the PSK warbler.

Lee - AA1YN

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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