[DSP-10] A version of UHFA without error checking

[Rich Miller]

Hi Mike:

Ok we are making progress!

When I began to prepare a new installation of another ADSP-2185, I noticed something looked amiss around pins 5 and 6. Closer inspection under a magnifying glass showed there was a small solder ball which was causing a short between these pins!  Once I removed it, I regained communication via serial port! This looked like it could have been there for a while and while handling the DSPx board it may have pushed into a position which caused the short (who knows).

Now what I am seeing is; I can lock the PLL in RX Mode and it will remain stable. If I do a transition from RX to TX the PLL becomes unlocked. When I recover back to the RX mode I notice there is a large delay in S-Meter indications, A/D Level Indications, and D/A Level Indications. The other concerning thing I am seeing is; when the D/A Level seems to come and go. It will be almost full scale, and then drop to nothing for no apparent reason.  

I am using UHFA394.EXE which I think is the latest.

73

Rich, AJ3G
703-409-1288

> On Dec 17, 2015, at 11:14 AM, kd7ts <kd7ts at comcast.net> wrote:
> 
>> On Thu, 17 Dec 2015 07:11:50 -0800, Richard Miller <av8torrich at yahoo.com> wrote:
>> 
>> I worry this may be a failed ADSP-2185N.  I do have another one I could solder on, but I am trying to make sure it is needed before doing so.
>> Rich
> 
> Hi Rich,
> 
> Afraid I can't offer more help. I think your trouble shooting is spot on. I don't know what to look for on the 2185. Obvious things are the voltages. The '2185 is a low voltage device, 3V ? and then there are a couple of chips that change the logic levels. I seem to recall all the PF signals are conditioned. Need to find out what normal conditions should be, and where.
> 
> If there are questions about voltages, I can measure mine and report. I would not suspect the ADSP-2185. If I had it here, the first thing I would do is take it out to the shop and blow some compressed air through it. Then pull on every connection that has heatshrink over the terminal.
> 
> I have had issues with the feedthroughs being soldered on both sides then when the inside connection of the box is heated, the outside becomes unsoldered, but still held in place by the heatshrink. This was a really tough one to find as it looks OK visually. Pulling on the wire will reveal if it is connected mechanically. Look at board connectors and be sure the guts haven't pushed back up the housing.
> 
> Mike KD7TS