[DSP-10] Problems Loading UHF3x35A.HEX

[Richard Miller]

Hello Bob:
When I came home this evening, I once again am unable to communicate with the DSP-10. I have a slimmed down version of UHFA which Mike provided me, and this too is not providing a satisfactory response either 
For this reason, I have contacted another member on the usergroup/reflector to purchase his ezlite kit. I am hoping this will allow me to once again regain serial control over the rig. If the problem still persist, I will start looking for a substantial voltage drop in the area of the voltage regulators and the PLL circuitry when I engage the transmitter.
To answer your question regarding whether or not the problem is present when at idle in CW or engaging the CW key, it happens regardless. It seems is the transition itself which seems to be the problem. There have been a few times where I was able to complete the transition since the problem started, but it is very rare, and if I do it again, I 100% of the time have  PLL Lock issue.
For the near term, I guess there will be no good gossip as to my status on 75 meters ! :)
73
Rich, AJ3G 
 

      From: Bob Larkin <boblark at proaxis.com>
 To: Richard Miller <av8torrich at yahoo.com>; "kd7ts at comcast.net" <kd7ts at comcast.net>; Rich Miller via DSP-10 <dsp-10 at mailman.qth.net> 
 Sent: Friday, December 18, 2015 12:16 PM
 Subject: Re: [DSP-10] Problems Loading UHF3x35A.HEX
   
Hi Rich,

The regular morning discussion of your DSP-10 between Mike and I 
suggested that there be some element that is used by the PLL and also 
changes between T and R.  There is not much!  The frequency does not 
change. Neither doe the load on the VCO.  The software that programs the 
PLL is the same.  The one possibility that does change is the load on 
the power supply.  Adding the transmit mA might cause a voltage problem 
at the PLL or elsewhere.  See if you can find a DC voltage change on the 
output of a regulator, or at the PLL.

Also, U104 is unlikely, as it is run the same in T and R.  But, anything 
is possible.

Also, is it the same in all modes?  especially, if you go into transmit 
in the CW mode, but do not actually send RF, is it the same?  i.e., does 
PLL loss happen at the T/R change in CW?

73, Bob

On 12/18/2015 07:52 AM, Richard Miller wrote:
> Hello Mike:
> Yes I have checked and the modification was apparently done when I built
> it. R108 does in fact read 472.
> With regard to Lock recovery after the transition, the answer is no.
> Once the lock is lost, it take a complete reload of UHFA394.EXE and a
> reset of the DSP board to recover from this. There are also other
> issues, such as the one I mentioned about the intermittent A/D level.
> When I say intermittent, I don't mean the level is fluctuating, but
> instead is completely absent. I have also seen cases where I would leave
> the system sit for a half hour, when in a faulted state, and it
> miraculously recovers on its own with no intervention from me (i.e.
> poking or prodding the PCB's).
> Last night I rewired everything, I thought maybe I had an intermittent
> in the wiring harnesses. I have rewired everything inside the DSP
> enclosure, and the harness leading from the DSP harness to the DSP-10
> main board. This too has left me with the same faults.
> With regards to frequency changes while in RX, I am able to navigate the
> entire 144 - 148 MHz span in large sections without a PLL lock warning.
> I think it may be time to look at replacing U104, and if that is not the
> issue, then the only thing left is something on the DSPx board.
> 73
> Rich, AJ3G
>
>
>