[DSP-10] Moth balled DSP-10 has some troubles

[Don AE5K]

Hi Mike and Bob (and anyone else following my saga)...

I'm back and didn't drop off the edge of the earth. Just too many things 
got in the way like the 4SQRP conference OzarkCon, household duties, and 
a quick excursion with an old Icom PCR-100 trying to listen for a new 
1296 (cw) beacon - which is fun without a BFO.  I even finally found the 
very old Toshiba laptop (ca. 1995).

The old laptop boots to the DSP-10 software using a floppy disk. Hooked 
everything up and have done the download from power up at least a dozen 
times.  No problems at all. With my trusty KA7EXM power meter (Kanga 
version), I measured an output of +2.5 dBm (1.78 mv) with or without my 
40 dB tap (so I left the tap installed). This was done at least 6 times, 
probably a lot more, and it was very consistent each time.  No problems 
noted except of course the much lower than expected power output.

Next, I went back to using my Dell 610 laptop, just changing the RS232 
serial connection -- all other setup connections the same. This laptop 
boots up using a CD-ROM I made.  In each case, I'm booting to MSDOS.  
During all the times I tried booting from power up, it hung one time at 
the "UHFA 1" command to load version 3.80 (same version on both 
laptops).  I've noted that it seems to take much longer with the Dell 
before the opening title/text page of 3.80 comes up than with the Toshiba.

Now, the interesting part: the power output measured by the meter is 
+3.6 dBm (2.31 mv) and this was absolutely consistent throughout all the 
power up boot ups.

So, of course, I went immediately back to the Toshiba set up, and now, 
it too was showing +3.6 dBm very consistently.  I tried about 10 power 
ups / boot ups.  And then again back to the Dell, and it still showed 
+3.6 dBm output.

There still may be a problem with the newer Dell laptop in the 
downloading, but that seems to be minor right now and not worth pursuing 
at this time.  The previous actions a couple weeks ago are still 
unexplained mysteries too, but they have not manifested themselves today.

Now the major task seems to be finding the reason for the low output.  I 
will start with that later today or tomorrow, and any ideas would be 
welcome of what to check or where to start.  I have the KA7EXM power 
meter, digital multimeters, a r.f. probe (diode, cap, resistor type), HF 
scope, etc.  I have the DSP-10 cover off and ready to go.

As far as I can tell, everything else is working with my DSP-10 -- at 
least at this stage I have not found anything not working that I've 
tried.  Stability is quite good, listening to a 144 MHz marker for an 
hour with only 10 Hz. drift (in the marker and/or DSP-10?).

As always, thanks for help...

73,
Don AE5K