I can confirm Eric's statement. One of our three SDR-1000 systems had this
problem. Cooling down the AD9854 helped temporarily. Then I installed a
bigger heatsink that worked a couple of weeks until the synthesizer got
damaged so badly that it did not work any more with any version of the
PowerSDR software. Amazingly though, with one of our own small test program
it still worked. However, for fully functional tasks of the PowerSDR the
chip had to be replaced.
For locating the malfunction, perhaps my private message earlier to Wayne
may help if anybody else happens to have this same problem:
--
Wayne,
This is just an educated guess. Try to measure the quadrature DDS signals at
U1B pin 6 and U1A pin 7. If no square wave signals present, use cold spray
for cooling AD9854. If that brings the signals back, you should know the
problem. Use the cold spray very selectively to one component at the time,
because the overheating problem may be also on the less expensive
components.
--
Good luck, if you decide to repair the radio yourself. Safer method may be
what Eric suggests.
73,
Ahti OH2RZ
----- Original Message -----
From: "Eric Wachsmann - FlexRadio" <[EMAIL PROTECTED]>
To: "'Wayne Roth'" <[EMAIL PROTECTED]>; <FlexRadio@flex-radio.biz>
Sent: Friday, September 30, 2005 11:30 PM
Subject: Re: [Flexradio] Receiver dies 2 min after power-up, ideas?
This is exactly what it looks like when/if the DDS quits running.
Contact us directly about getting the unit serviced. You might look
through the various ECOs on the private downloadp age if your unit is
not up to date.
Eric Wachsmann
FlexRadio Systems
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
radio.biz] On Behalf Of Wayne Roth
Sent: Friday, September 30, 2005 1:57 PM
To: FlexRadio@flex-radio.biz
Subject: [Flexradio] Receiver dies 2 min after power-up, ideas?
My SDR-1000 (an older rev box with RFE, no PA or tuner, parallel port
interface) receives fine for the first couple of minutes then goes
deaf.
Cycling the DC power restores the receiver for another couple minutes,
then
it dies again. Just before it craps out, the baseline as viewed on
the
spectral display raises from -130 to about -70 a couple times along
with
an
increase in the white noise, then drops to -140. All frequencies
appear
to
be dead. Restarting the software has no effect, so it's a hardware
issue.
I have yet to open the enclosure and get the scope out, just wondering
if
anyone has seen this, or has a suggestion on where to start looking.
Best Regards,
Wayne
WA2N / 5 Austin Tx
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