[PCR-1000] no receive
Mike Curtis
mcurtis at nc.rr.com
Sun Jun 19 14:50:16 EDT 2005
I agree with your thoughts on switching power supplies. I had what was
supposed to be a low-noise ham type switching power supply. If I left it
running for more than a day my DC powered radios would pick up an annoying
low level hum and an intermittent hissing problem. I replaced the switching
power support with a nice linear power supply. The linear supply is totally
silent. I end up leaving it powered up 24/7 and I turn the radios off when
they are not needed.
Don’t waste you money on a switching power supply unless you have to. I
know they claim to be low noise, but even the best ones can't match a nice
linear power supply...
-----Original Message-----
From: pcr-1000-bounces at mailman.qth.net
[mailto:pcr-1000-bounces at mailman.qth.net] On Behalf Of Folke Persson
Sent: Sunday, June 19, 2005 12:27 PM
To: 'Discussion of PCR-1000 by Icom'
Subject: SV: [PCR-1000] no receive
No switching PS in my schack!
The self-oscillating problem in the AR-3000 acts
like a u-wave sensor when the problem is present
(loud roaring sound through the speaker), it sometimes
sense the hand up to 10-15 cm in front of the radio.
I can assure I have had the radio on the repair bench
several times, trying to pinpoint what component is
starting the oscillation, but of course then it can act
normal for days and weeks....)
BR
Folke
-----Ursprungligt meddelande-----
Från: pcr-1000-bounces at mailman.qth.net
[mailto:pcr-1000-bounces at mailman.qth.net] För R. J. Grasser
Skickat: den 19 juni 2005 15:22
Till: Discussion of PCR-1000 by Icom
Ämne: Re: [PCR-1000] no receive
Its always a good idea to turn off any "gear" at its power switch before
shutting down an external powersupply.
Your symptoms are typical of switching powersupplies that induce all sorts
of noise at certain frequencies, and it doesnt actually have to power the
device, just be within the immediate area. Thats why I only use linear
powersupplies.
Just a thought. You might have a different problem though.
Regards, RJ
----- Original Message -----
From: "Folke Persson" <fp01 at telia.com>
To: "'Discussion of PCR-1000 by Icom'" <pcr-1000 at mailman.qth.net>
Sent: Sunday, June 19, 2005 1:36 AM
Subject: SV: [PCR-1000] no receive
Speaking about slow starting and stopping powersupply.
I have a simular problem with my AR-3000. The powersupply is a quite heavy
duty 10Amp unit with large capacitors, and there are lots of other radios
beside the AOR AR-3000, but this radio need to be switched off/on with it´s
own switch,
otherwise at 1 out of 3 times it drops the memory, all channels and
frequencies has to be reprogrammed. It has a lithium back-up memory but this
is checked OK (and replaced). Another strannge problem has followed this
radio since it was nearly new:
>From time to time it starts to oscillate internally, often when
>receiving a
somewhat
weak and noisy signal. This can be heard as a strange and roaring sound in
the speaker but as soon as you only set the hand about 10cm in front of the
radio it stops. Very annoying..
There could be several weeks between the faults, or several times on a
day.... Any tips on the cause and solution for this is most welcome.
I have a PCR-1000 to, it has not so far (3 years) failed.
/Folke SM7HMS
-----Ursprungligt meddelande-----
Från: pcr-1000-bounces at mailman.qth.net
[mailto:pcr-1000-bounces at mailman.qth.net] För Darrel Emerson
Skickat: den 18 juni 2005 17:40
Till: INTERNET:pcr-1000 at mailman.qth.net
Ämne: RE: [PCR-1000] no receive
About the PCR-1000 going deaf:
I still have an early PCR-1000 receiver, and have been following this
list more or less since the beginning. I think that the business of
third-party software causing the problem was something put out by Icom as a
way of blaming someone else. From following this list, I believe there have
been quite as many EEPROM corruptions from people using Icom's own software,
as from use of any third party software - but Icom always denied that.
I still use the same PCR-1000 essentially daily.
I had no problems with the PCR-1000 for 6 years, and then one day the
EEPROM corruption struck, At the time I was using Win98, and had been doing
so for some time. Fortunately I had an EEPROM backup, and after EEPROM
restoration the PCR-1000 was back on the air, as good as new, in no time.
It's been running since then for a couple of years. Before restoration I
made a temporary backup of the corrupted EEPROM and examined it. It wasn't
just a single byte here or there, but essentially all of the EEPROM bytes
had been replaced by Hex#80.
I never found what had caused the corruption after 6 years of no problem.
It might
have been Windows interrogating the serial port. Another theory is that it
was my power up sequence; I use relatively heavy duty 12 V power supply, and
was in the habit of leaving the PCR-1000's own power switch turned on, and
just powering up or down with the 12V PSU switch. I could imagine that,
particularly after I turn off the PSU power, the nominal 12 V output
decreases fairly slowly as capacitors discharge.
You could imagine then that the slowly falling low voltage that's still
applied to the PCR-1000 might cause the logic to get into some strange state
which could occasionally erase the EEPROM. "Occasionally" could be once in
every 2000 power cycles, or about once per 6 years.
This is just a theory. Since that one EEPROM corruption, I've made a
point of only turning on the PCR-1000 at its own switch after my PC has
booted up, and after the 12 V PSU has been turned on. Similarly, before
powering down, I first turn off the PCR-1000 at its switch, before shutting
down the PC and powering down the
12 V PSU. Since doing that, there have been no further problems - at least
for
2 years or so. But then, it took 6 years for the first and only problem to
appear, so I guess I have to wait for a few more years to know if my better
power up and power down sequence actually makes any difference.
Good luck,
Darrel Emerson.
Original message: -----------------------
Message: 1
Date: Fri, 17 Jun 2005 17:46:21 +0100
From: "Dave Hancock" <dave at davehancock.org>
Subject: RE: [PCR-1000] no receive
To: "'Discussion of PCR-1000 by Icom'" <pcr-1000 at mailman.qth.net>
Message-ID: <20050617164705.B0C97859C28 at mailman.qth.net>
Content-Type: text/plain; charset="us-ascii"
Hi Chuck,
My unit was deaf on 137mhz but was receiving FM broadcasts ok. I cured the
problem by loading on a copy of a working EEPROM I got from
http://sean.wenzel.net/lists/PCR1000/0413.html. I then used TalkPCR to make
a backup of my original, renamed it and then renamed the downloaded version
so TalkPCR thought it was my backup and restored it.
This certainly cured my problem and as long as you can make a backup of your
original you are not going to be any worse off.
Drop me a private mail if you have trouble finding any of the above on the
web and I will send you a copy.
Good Luck!
Dave
Dave at davehancock.org
-----Original Message-----
From: pcr-1000-bounces at mailman.qth.net
[mailto:pcr-1000-bounces at mailman.qth.net] On Behalf Of Chuck Nitsch
Sent: 16 June 2005 01:11
To: Discussion of PCR-1000 by Icom
Subject: RE: [PCR-1000] no receive
Here is what I know for sure... It's not the cable and it's not the
computer.
I have tried to tune both AM and FM broadcast stations, but I get nothing
other than speaker hiss / noise.
I've considered perhaps it's the EPROM, but I don't have a backup.
Has anyone here had the experience of having an Icom go deaf (excluding
white noise from speaker) and subsequently do an EPROM restoration and fix
the problem?
<
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