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

[Don AE5K]

Hi all,

My DSP-10, built many years ago (2003?) and hardly used, has been fed 
some more power with the hope it will come to life and be useful in a 
1296 transverter operation.  But I've run into a problem with it.  Let 
me describe...

I am using a KA7EXM power meter (Kanga version) on the transmit output 
of the DSP-10 with a 40 dB pad. At times with CW mode, 100% power, I 
press the keyboard HOME to go to transmit and I have no output until I 
press the CW key.  And then it measures only in the 0.8 mw region. At 
other times, I press HOME for transmit, and I have the same 0.8 mw 
output *without* key down.

I took the 40 dB pad out since the power meter can stand +7 dBm.  I got 
the same readings (accounting for the missing pad), except that while in 
that mode without key down I get 0.8 mw out, I then press the CW key and 
the meter zooms to a 8 WATT reading.  Of course I haven't held key down 
very long and there has been no smoke or change in operation.

In addition, with a different laptop than from years ago (it is now a 
Dell 610), I boot with a CD-R into MSDOS 6.22.  It works some of the 
time, but earlier today when booting that way, I had to do it three 
times before it went all the way properly.  I mention this as it could 
be related I suppose to the main problem.  (Several years ago, the CD-R 
boot worked like a charm every time so I know it is correct.)

Any ideas of where I can look?

So far, I'm suspicious that maybe the two 595 shift registers are acting 
up when I go from receive to transmit.  And that the 0.8 mw that I'm 
getting is possible feed thru from stages before the 2N5109 final amp. 
And that when the 595's shift properly, and I go key down, the DSP-10 is 
really putting out the 13 dBm or so ("pegging" the digital power meter). 
  The erratic operation is puzzling, and could be signs of some kind of 
timing problem I suppose.

Help would be appreciated.

73,
Don AE5K