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Re: #qcx #smoke #qcx #smoke

g4edg
 

Hello Kalle

Same thing happened to my QCX just yesterday.....huge amounts of smoke from one of the BS170 PA, upon testing all three were blown....Q6 also short circuit, but also had a huge crack in it. 

Receiver and display still works.

I have ordered a MPS751 for the Q6 replacement ...its Ic is 2A as opposed to 600mA for the MPS2907 used in my rig. This is now used in the latest version of the kit.

I intend to see if all is well after replacing Q6 by connecting a resistor in place of the PAs just to check if there is anything downstream causing Q6 to be switched on permanently before I replace the BS170s ....though I have checked thoroughly that this is not the case.

Good luck getting your rig going again.

73 Steve G4EDG

Re: #qcx #smoke #qcx #smoke

Kalle Johansson
 

Hello Alan tnx for good reply. Yes indeed the Q6 was also shot.I took off Q1,2 & 3 and put on the display again. The RX and display still works like a charm and I could see the pulse train on the gates coming from IC3 when I key the TX so that seems fine too. The Q6 was shorted however because it was feeding 12V all the time to the finals. This was just like last time and I have some spare PNP's for the Q6. When some new BS170 arrives in the mail in a few days it should be fine.

I will tidy it up and test/measure the TX and report back

73 de SM3LXI /Kalle J.

Re: 30V @ 10A Variable Voltage Switching Mode Power Supplies

Jim - W7EZN
 

On Fri, Dec 27, 2019 at 08:05 AM, Paul Kelley wrote:
Eventec KPS3010D
Paul--  I use a Jameco part number 29226.  Its a linear amp that provides both pos and neg voltages.  It powers my QCX's, a uBitX and an old Yaesu FT-4700 2 meter/70 cm x-ciever that is my 'base' unit.  Inexpensive and you get to do a little soldering to make it more fun!
 
--
Jim, KJ7EZN    73!

Re: QCX Unreliable operation with GPS connected

Don DeGregori
 

What I did was add a tiny DPST switch before the cable that goes to the QLG1. Going to Beacon mode I first close the switch. Going to CW I open the switch. Any switching should be done with power off. Then power up  QCX. The pins being switched are the bottom two. Remove key in Beacon mode. Later I changed the switch to a 5 pole DIP switch. Now when I switch, I disconnect all wires going to the QLG1. Power pins, the 2 data pins and even the shield ground. The cable I use is a piece of USB cable. Use the shield, connecting to QCX end only. The mounting hole near the pins is at ground. Switching QLG1 off in CW saves current for portable operation.

Don

Re: #qcx #smoke #qcx #smoke

Alan G4ZFQ
 

?One of the Q1,2,3 blew and I could figure out which one by
taking them off and ohm-measure them. Then i replaced the one I thought was faulty and put one new in and tried again. Same thing and now two of them was broken.
Was it a mistake not to replace all three of them?
Sometimes more than just a BS170 is damaged. In any case it is not a good idea just to replace one, the others might have been damaged and have a short life.
Sometimes Q6 is damaged, no real problem.
But sometimes Q3 is damaged, possibly by a drain/source short putting 12V on pin 3. In a few cases this 12V may have travelled further to damage the Si5351 or IC2.
Remove all BS170s, measure voltages at their pins and at all IC3 pins RX and TX.
If the display works with no error message the SI5351 and IC2 are hopefully undamaged.

73 Alan G4ZFQ

#qcx #smoke #qcx #smoke

Kalle Johansson
 

Boxing Day Holy Smoke!

Hello again I have been fortunate for a long time and been running my little QCX in WSPR mode non-stop for many months. I have replaced my Q1, Q2 and Q3 once before after some over voltage/antenna mishap.

Now it happened again after trying to fit some usable GPS connector on the box. One of the Q1,2,3 blew and I could figure out which one by taking them off and ohm-measure them. Then i replaced the one I thought was faulty and put one new in and tried again. Same thing and now two of them was broken. 

Was it a mistake not to replace all three of them? Or am I having another condition that will generate holy smoke even if I put in three new ones?

Any good leads are appreciated 

73 de SM3LXI

Re: LC-100 L and C meter

Jim Mcilroy
 

I have a Peak LCR45 also

I used it to measure the toroids for the QCX and mighty useful it was too.

Jim

On 28/12/2019 12:47, George Korper wrote:
The Peak looks like a good buy. Thanks!!!!
Have you measured toroids from the kit?

On Sat, Dec 28, 2019 at 10:38 AM Trystan G0KAY <trystandavies@...> wrote:
I've got a Peak LCR45 LCR meter and works very well indeed. Designed and manufactured in the UK too. Peak provide aftersales support, accessories, repairs and calibration options. I'm delighted with the little thing.

Re: LC-100 L and C meter

George Korper
 

The Peak looks like a good buy. Thanks!!!!
Have you measured toroids from the kit?

On Sat, Dec 28, 2019 at 10:38 AM Trystan G0KAY <trystandavies@...> wrote:
I've got a Peak LCR45 LCR meter and works very well indeed. Designed and manufactured in the UK too. Peak provide aftersales support, accessories, repairs and calibration options. I'm delighted with the little thing.

Re: LC-100 L and C meter

Trystan G0KAY
 

I've got a Peak LCR45 LCR meter and works very well indeed. Designed and manufactured in the UK too. Peak provide aftersales support, accessories, repairs and calibration options. I'm delighted with the little thing.

Re: QCX Unreliable operation with GPS connected

George Korper
 

And make sure your key is not in the jack. Pulling it out can cause a problem, with the radio on while it is running.

Re: QCX Unreliable operation with GPS connected

George Korper
 

Regardless of the "Fix" by going into practice mode, etc I read in the revision, personally I would not connect
the OLG1 unless it was all set up in Beacon mode. Then I would disconnect it to use the radio. Something is wrong.
It is serious because not all of us have the spare parts to fix a radio,
even if we were as good as some members at diagnosing the problem.

Re: Missing QCX rotary encoder and NAND question

Rob W2ITT
 

Thanks much for the quick responses Bob and Chopper. Have a good weekend.

Rob

Re: Missing QCX rotary encoder and NAND question

N3MNT
 

They are both plastic dual inline packages just different vendors same specs.

Re: Missing QCX rotary encoder and NAND question

N3MNT
 

On Fri, Dec 27, 2019 at 06:25 PM, Bob ZL1RS wrote:
74ACT00PC

Re: Missing QCX rotary encoder and NAND question

Bob ZL1RS
 

There is a 74ACT00PC in my QCX, it is working fine.


Missing QCX rotary encoder and NAND question

Rob W2ITT
 

Hi all,

Opened my QCX today and inventoried the parts. The rotary encoder was not included, I'd like to source a replacement in the US if possible. I found this searching the group:

 https://www.amazon.com/Position-Degree-Rotary-Encoder-Button/dp/B00KHTLWU6/ref=pd_cp_75_2?_encoding=UTF8&pd_rd_i=B00KHTLWU6&pd_rd_r=43GQ62FHJCPMYZFZWWS0&pd_rd_w=r7T0H&pd_rd_wg=C5IpS&psc=1&refRID=43GQ62FHJCPMYZFZWWS0 

but it would take as long to get this as it would for me to get a replacement from QRP Labs and I don't need 3. Does anyone have a better source?

Also, IC3 is documented as a 74ACT00N, I received a 74ACT00PC. Forgive my ignorance, but does this make any difference at all?

73,
Rob

Re: QCX Unreliable operation with GPS connected

George Korper
 

Yup I found out the hard way when I forgot to do that last month. 
Failure to be very observant puts you in REPAIR Mode. 

Re: QCX Unreliable operation with GPS connected

Don DeGregori
 

The GPS module is not supposed be connected when using CW node.

Re: LC-100 L and C meter

Jerry Gaffke
 

The old "qrp-tech" yahoo forum has been archived on groups.io,
That group is locked down and inactive, just an archive.
Everybody has moved over to "QRP Tech", with a new moderator.

Here's a search for "LC-100 K7QO", finds finds a dozen or so messages:
  https://groups.io/g/qrp-tech/search?ev=false&q=LC-100A++K7QO

Jerry, KE7ER


On Thu, Dec 26, 2019 at 07:52 PM, Ted KX4OM wrote:
Chuck, K7QO did a test of his LC-100A eBay capacitor and inductor checker and published the results. Maybe it was transferred to the new qrp tech groups.io forum. I did a similar but not as exhaustive test of my LC-100A (eBay, $14, two stacked boards, not a kit) and got the same excellent performance as Chuck's. It is good to the single-digit pF range. and uH range. I've used it to check a lot of homebrew toroids and capacitors for homebrew audio oscillators and VFOs, and I've checked and cataloged all of my many unmarked large and small variable capacitors.

Don't confuse these LC-100A L-and-C-only check devices with the "transistor tester" ($20 lcr-esr..) ones. Those are much more capable active semiconductor testers as well as R-L-C. There is very active eeblog development of the transistor testors. The link to that blog is mentioned in other posts here. There are two separate tracks of development ongoing, both springing from the orignial work of Markus Frejek. The latest information can be typically obtained by reading the newest 10 pages of the eevblog, including an updated instruction manual.

Some of the eBay/Amazon/wherever testers have soldered SMD Atmega328 devices that can be updated only with new software using in-circuit programming; others with removable ATtmega328p 28-pin dip chips can be programming out-of-circuit. I had to do that with the first one (kit) I bought from eBay. The kit did not actually have the ATmega328 DIP chip included. Instead, it had two DIP sockets taped back to back, exactly as in the photo of the kit on eBay, as I discovered on close inspection! I had to buy an Atmega328P and program it with an AVR programmer.
--
Ted, KX4OM

Re: QCX Unreliable operation with GPS connected

Gregg Myers
 

I also note some display/button weirdness GPS connected and 1.03 firmware that I didn’t notice with 1.02 and earlier. But it seemed to be just display artifacts. Since I only had the QLG1 connected very infrequently,(just for calibration). It didn’t really bother me very much. It may be that you won’t see the artifacts if you plug the GPS in while on the 8.13 menu and wait for it to acquire the GPS signal. But I didn’t test it very thoroughly. 
73, Gregg

On Fri, Dec 27, 2019 at 6:41 AM George Korper <georgekorper@...> wrote:
Hi,
Well that's irritating! Did you swap out the firmware from an earlier version? I ask because I am about to start building a new one.
On your last question,I wondered the same thing about WSPR and I tried 2 different Sotabeam WSPR  units and OLG1 on the QCX. For me in the last week
40 meters on two different antennas has been weird lately. Very high noise levels. My SDR is all awash with noise as well. Christmas, Santa,
lighting next door, I just hope it goes away after the Holidays. I went nuts looking for the noise, but hoping it disappears on its own.
I have a remote rig a couple of thousand KM away in the country away from the lights and it show high noise as well. The sun has new cycle reverse polarity sunspots perhaps it is the sun (hi hi)
73's,
George