Re: QDX - No RF output, Tx line stays low
Hello Jay,
FWIW, I had to replace IC5 after determining that it was not working.? I removed the 4 BS170 MOSFET finals and then tested the output of IC5 to the gate pads.? One side had nice square wave signals, the other did not.? IC5 was bad, probably taken out when the finals became resistors and not MOSFETs anymore.
To repair IC5, I simply cut off all of the leads of IC5 with a fine diagonal cutter right next to the IC.? Clip parallel to the chip side to reduce any strain on the pad.? ?I then cleaned off the left behind leads with my iron and solder wick. Then installed the 74ACT08 replacement.? I verified that the drives to the gate pads were correct (On the first test I found that one of the output leads of IC5 had a cold joint) and then installed the BS170s.? I would have had issues if I had not found the joint issue with one of the pins on IC5.
You might want to replace all 4 of the BS170 MOSFETs while you are at it.? The ones that check out as OK could be weakened, and they are not that expensive.? Better to start with a fresh set of tested BS170s.
If you do decide to use Chip Quick be sure to clean off all of the solder after the removal of the IC as per the instructions.? That solder is very brittle and will cause long-term issues if not removed properly before installing the new part.
Good luck with the repair.
73
Evan
AC9TU
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Re: QDX - No RF output, Tx line stays low
Hi Ben, Congratulations on finding the problems and the QSO. FYI, I too have the issue of needing to power cycle the QDX a number of times to get a connection.? I have the issue on more than one Windows PC, so it is a compatibility question with Windows.? As Hans has stated he has not done extensive testing with Windows as he has a long startup situation with his current Windows PC.? I was given a tip to disable the suspend function for the USB connections.? That may have helped in reducing the reoccurrence of the problem, but I was able to connect prior to making the change.? The tip is in this message from Gregg Myers: /g/QRPLabs/message/74548I have found that after I get the QDX connected it does work well. 73 Evan AC9TU
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Re: Revisiting a Ultimate3S case shipping question.
No, still waiting on mine.
On 11/13/2021 7:35 PM, Larry
Christensen wrote:
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Has anyone received a case for the?Ultimate3S
lately???
It was pasted off the the
airmail carrier 8 weeks ago today.
The latest tracking is
attached.?
Thank for any information you may have.?
p s I know about covid etc etc. I¡¯m just wondering if anyone
has received a case from China.?
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Re: QDX - No RF output, Tx line stays low
I resolved my problem today, not a hardware problem (the rabbit hole I went down initially) but a computer issue. ?Setting both the computer audio output and the power level in WSJT-X at maximum, and trying a few different USB cables, I got RF output: ?80M, 5.6W; 40M, 5.2W; 30M,5.5W; 20M, 3.6W. ?I had a couple QSOs on 20M, and saw many spots on PSKReporter. ?I found it was necessary to connect the USB cable between the QDX and the computer (Win10 laptop) BEFORE powering on the QDX (9V) to get the computer to recognize the rig. ?I found it was sometimes necessary to repeat the process of turning on the QDX then launching WSJT-X a couple times to establish a connection. ?I suspect it is more an issue with this particular PC than with the QDX. ?So today zi am a happy camper!
73, Ben ?K0IKR
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Good idea, Jeffrey.? Thanks.
Mike
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Thanks, Julian.? T1 primary and secondary are not shorted so we're good there.? We have not gotten to T2 yet.? We appreciate your feedback.
73, Mike KK7ER (and Wesley, N7BIN)
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Revisiting a Ultimate3S case shipping question.
Has anyone received a case for the?Ultimate3S lately???
It was pasted off the the airmail carrier 8 weeks ago today.
The latest tracking is attached.?
Thank for any information you may have.?
p s I know about covid etc etc. I¡¯m just wondering if anyone has received a case from China.?
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You can use a little clear nail polish to cover the nick in the
insulation to seal it back up. I would make sure you have the right
number of turns and spacing before dropping a tiny drop, just in
case it sticks to the core. I've had to cover several spliced toroid
windings on some BPFs I built, and they have all worked out well.
Just know that flexing that area may cause the polish to crack or
flake off, which is why I suggest waiting until you're certain
before applying. Good luck!
Jeffrey
On 11/13/21 15:39, Mike KK7ER wrote:
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My 11yo son and I are doing the QDX build together.? His young
eyes are great for finding potential issues.? We are going at a
very slow pace and benefitting greatly from all the
troubleshooting stories here on groups.io.??We are taking turns
winding toroids and it was his turn when we got to L14.? The #22
wire is pretty stiff and it takes a little extra force to pull it
through.? He started noticing nicks in the enamel and was a bit
concerned about it.? I told him I'd run it past the experts in the
forum here before we soldered it onto the board.? Some have
reported having to replace toroids with shorted turns.? These
nicks do not seem that significant and the turns have space
between them (except in the center of the toroid).? I attached a
picture below with some nicks circled.? The first one in the
rightmost picture is lined up just right to come into contact with
the core.? So the question is:? should we proceed or stop and buy
some more #22 magnet wire?? Thanks for any advice.
73, Mike KK7ER
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Re: QDX - No RF output, Tx line stays low
John, thanks for the tip it¡¯s coming tomorrow.
On Saturday, November 13, 2021, 3:30 PM, John AE5X <ae5x@...> wrote: On Sat, Nov 13, 2021 at 03:44 PM, Jay Gustin wrote:
about how to remove while the replacement?part is in transit.?
Chip Quik is probably the safest way to do it. Runs about $12 on Amazon: ? -- John AE5X
--
Jginaz
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For those toroids you're probably OK, because the turns are spaced, but for T1 and T2 it is CRITICAL that you do not scrape off the insulation. I've written about this at least twice - once mere moments ago.
To be specific: Contact with the core is not a problem, but contact with other windings IS.
--
Julian, N4JO.
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My 11yo son and I are doing the QDX build together.? His young eyes are great for finding potential issues.? We are going at a very slow pace and benefitting greatly from all the troubleshooting stories here on groups.io.??We are taking turns winding toroids and it was his turn when we got to L14.? The #22 wire is pretty stiff and it takes a little extra force to pull it through.? He started noticing nicks in the enamel and was a bit concerned about it.? I told him I'd run it past the experts in the forum here before we soldered it onto the board.? Some have reported having to replace toroids with shorted turns.? These nicks do not seem that significant and the turns have space between them (except in the center of the toroid).? I attached a picture below with some nicks circled.? The first one in the rightmost picture is lined up just right to come into contact with the core.? So the question is:? should we proceed or stop and buy some more #22 magnet wire?? Thanks for any advice.
73, Mike KK7ER
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Re: Qdx smoked - USB
#qdx
It is just as possible - in fact more so, because of the number of turns - to short the windings of T2. The results aren't as spectacular, but certainly as frustrating. I wrote a warning about the sharp edges? of the inner edge of the toroids in my post on the subject a while back.
--
Julian, N4JO.
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Thanks for the link! DE KJ7YYM
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Re: Qdx smoked - USB
#qdx
It is possible to get a short inside of T1 and I think this happened to someone else that?I read about. The short happens because when winding the #22 wire through the binocular, some of the wire insulation gets scraped off the wire and the exposed copper *might* touch inside the core. I observed that the wire insulation was scraped off in places when I wound my T1 winding, but since I checked primary to secondary with an ohmmeter before I installed it, I left it as is. And so far, mine has been fine.
In the 50W Amplifier instructions, I seem to recall there is a recommendation to de-burr the openings of a?binocular so this is less likely to happen. However, if you do that, be careful not to put too much pressure on the core as it might be possible to break it.
Good luck, Gregg W7GRM
Qdx powered up fine, then attached usb and it let the magic smoke out.?
Haven't had a lot of time to troubleshoot, but it is shorted between primary and secondary of t1. Previously during build, no short between primary and secondary.?
Headed out of town for a few days, so I won't be able to work with it. But any input is appreciated.
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If you have multiple coax lines coming in, you might look into getting a coax switch. Many will ground the lines in the unused positions and have a position that grounds all of them. That won¡¯t totally eliminate the dangers from a lightning strike, but in conjunction with the others might protect your transceiver.
¡ªMike Perry, WA4MP
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On Nov 13, 2021, at 9:34 am, richlim11 via groups.io <richlim11@...> wrote:
Wow! I¡¯ve alsways wondered about putting some lightning arrestors for my wire antennas but never have
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Re: BNC connector position on the QCX mini
Yes, it certainly shows you what the orientation should be when properly installed, but unfortunately you can't solder it in that way, because you can't get to the underside of the board. The precision of the kit parts is really good, so if you go for parallel you can't really go wrong.
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Julian, N4JO.
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Exactly.
If you need a trace to compare to, let me know, and I'll take a couple of snapshots for you.
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Julian, N4JO.
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Re: BNC connector position on the QCX mini
I have found that using the rear enclosure panel piece as a template when installing the connectors results in a much better fit.
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Re: QDX - No RF output, Tx line stays low
On Sat, Nov 13, 2021 at 03:44 PM, Jay Gustin wrote:
about how to remove while the replacement?part is in transit.?
Chip Quik is probably the safest way to do it. Runs about $12 on Amazon: ? -- John AE5X
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Re: BNC connector position on the QCX mini
Here are two pictures of what it should look lie: side?view and end?view.
The side view shows that the connector must be parallel to the board, not angled up or down (this picture shows it angled slightly down, which is technically wrong), and the side view shows the flat on the underside of the flange. You may need to file it slightly to allow the connector to sit parallel.
Also, I solder the front two retaining lugs first, so that I don't add stress to the electrical connections by soldering them first, then pulling the connector around to orient it correctly.
Hope that helps.
--
Julian, N4JO.
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Julian N4JO
Mike Perry, WA4MP
N3MNT