[hpsdr] Request for information

[Jim Sanford]

All:

Background:

Several months ago, while I was on a 75m sked with friends, my 
Atlas-based system (Metis, Mercury, Penolope, Alex) failed.  While I was 
waiting for replacement FETs for Munin, I replaced the Penelope board 
with the misplaced output transformer with a PennyLane board.

Repaired rig.

Noticed that if I connected the power sensor that comes from Alex thru 
Mercury to PannyLane, that an attempt would be immediately met with a 
shutdown, "Please check your antena connection."

After I replaced the output FETs in Munin, working great with clean 
output on waveform monitor and spectrum analyzer, and adjusted bias, it 
continued to generate heat.  Measured PTT line without PTT being 
asserted and it was 3.5-ish volts, not 8 volts, which I would expect 
based on schematic.  The rig would also immediately shut down with the 
above error warning upon initiating a two-tone test, despite drive setting.

I ruled out forward/reflected power sensor in Alex by substituting a 
new, never used Alex module.  Same result.

Installing a Penelope board with the right treansformer orientation did 
not have any of these issues.

Additional issues:  PennyLane was partially asserting PTT, 3.3+ volts on 
PTT line, instead of zero or  8 volts), so that Munin would draw bias 
current, generating heat and running the fan, without any PTT Input 
being asserted.  disconnecting PennyLane, the PTT line wen to 8 volts 
and the PA stopped drawing bias current.Hookikng pupower sensors does 
not generate the shutdown signal and command.

Tonight I replaced PennyLane with a  Penelope board.  Transmits fine.  
Connecting the cable from Alex, I get good Power and SWR readings.  I 
don't see the excessive current from Munin being biased during receive , 
and when  I measure the PTT line in reeceive, I see 8 volts, like I 
would expect.

SO, I expect there are issues with the PennyLane board.

1.   Doesn't interpret the dc voltages from the Alex board correctly.

2. The keying transistor (Q101 on Penelope) has excessive leakage.

3.  There is something wrong with how power sensor data is brought into 
PennyLane

4.  The PTT keying transistor has excessive leakage, or some other issue.

I have been unable to find any documentation on PennyLane, so I cannot 
determine what components to susp

I request the following:

1.  Any documentation on PenyLane -- I have found none on the OpoenHPSDR 
web site.

2.  Any suggestions on how to proceed further.

3.  Any other suggestions.

Thanks & 73,

Jim

wb4gcs at amsat.org