[DSP-10] DSP-10 Assembly Complete!

Sat, 13 Dec 2003 08:09:11 EST

In a message dated 12/13/03 12:39:51 AM Eastern Standard Time, 
[email protected] writes:

> I finished the assembly of my DSP-10 tonight!

Congrats John, I just finished mine also and had similar questions.

>  When I apply power the power led does indeed turn on, but after about three
>  or four seconds, so does the transmit led.  Is this correct?

Is SR105 installed correctly? This shouldn't happen.

>  Current consumption is about 450mA, which is a bit higher that the 350mA
>  stated in the procedure.

If the Red LED is on, you're in xmit. Measure the +10T and +10R rails. I bet 
they're both are at 10 volts. This is a bad thing. You only want the +10R on.

>  Most of the voltages are within a tenth of a volt or so - except:
>  
>  R110 = 1.81v  ------------- should be .23v

I got essentially the same thing and asked the same question here, but got no 
answer. I think this is probably OK. I see ~ 1.6 volts.

>  U105 pin 3 = 2.02v ------ should be 3.5v
>  U106 pin 3 = 3.79v ------ should be 4.6v

Have you measured the VCO freqs? I bet you find them a ways off. When you get 
them closer, you'll see the voltage pull in closer.

I saw 2.85 @ U105 and 4.2 @ U106 after a little tweaking on the vco...

>  R59 = 1.49v ---------------- should be 1.49v

This should be .91 according to the original article. I see 1.4 volts. Get 
Jimmy's article at:

http://home.teleport.com/~oldaker/dsp10_repository.htm
and download the dsp10_initial_testing.doc  131k

It has more realistic numbers for the TAPR kit. Good Luck!

73,
Mike, N1JEZ
FN34im
"A closed mouth gathers no feet."