Re: QMX: almost zero power out all bands
Yeah, what kind of throws me is I was very diligent about scraping off enamel on every toroid beforehand and double checking continuity. Oh well, back the soldering iron I go....
|
Re: QMX: almost zero power out all bands
First place to look from what I read is T507 and the solder connections. The heavy wire and ground plane make soldering difficult. If you didn't scrape the enamel off before soldering you will have difficulty burning it off. Takes lots of heat, but don't wreck the board either.
toggle quoted message
Show quoted text
On Jan 15, 2024, at 18:46, Larry VE7EA < lagagnon@...> wrote:
I recently finished building the QMX kit, 20-10m version, Rev 2. The receiver works great on all bands, and all systems function well except transmit. I have built 4 other QCX Mini kits successfully and yes, I suspect toroid shorting or lack of continuity in the Tx circuit somewhere but would like some hints as to where to start. (PS: all Tx testing was done with a 50 ohm dummy load/wattmeter). These are my symptoms:
- If ¡°Protection Enabled at SWR 3¡± and transmitter is keyed "S" immediately appears and no output - all bands
- If "Protection Disabled" quick key down at low voltage (9v on a 12v wiring) and test with nearby receiver shows extremely weak signal on 20-17m and slightly stronger signal 15-10m but QRP wattmeter reads nil
Given the lack of power out on any band I suspect problem lies before the band filters, and possibly around T501. However, if there is little to no power out why is the SWR circuit even involved?
Thanks for your attention.
Larry VE7EA
|
QMX: almost zero power out all bands
I recently finished building the QMX kit, 20-10m version, Rev 2. The receiver works great on all bands, and all systems function well except transmit. I have built 4 other QCX Mini kits successfully and yes, I suspect toroid shorting or lack of continuity in the Tx circuit somewhere but would like some hints as to where to start. (PS: all Tx testing was done with a 50 ohm dummy load/wattmeter). These are my symptoms:
- If ¡°Protection Enabled at SWR 3¡± and transmitter is keyed "S" immediately appears and no output - all bands
- If "Protection Disabled" quick key down at low voltage (9v on a 12v wiring) and test with nearby receiver shows extremely weak signal on 20-17m and slightly stronger signal 15-10m but QRP wattmeter reads nil
Given the lack of power out on any band I suspect problem lies before the band filters, and possibly around T501. However, if there is little to no power out why is the SWR circuit even involved?
Thanks for your attention.
Larry VE7EA
|
QMX worked briefly then died when adjusting... Help?
My QMX high band rev2 kit worked right away! Until I went to go do some minor adjustments to the 10m LPF and the SWR bridge (was reading 1.5-1.7 when into a dummy load) when it suddenly died.
Now, I have a strange set of symptoms. The main one is that I see 0.75V (stable on varying input voltage) on the lin_reg_en pin from the SMPS board #2, but nothing ever seems to bring up 3V3.
Current draw is consistently 0 even when pressing the encoder. The encoders seem to be making contact correctly as far as I can tell from testing on the controls board and the QMX main board.
It sure seems like something might have fried my linear regulator, but I'm not sure quite how to confirm and or if there's anything I can really do about it other than trying to order some replacement SMPS boards?
I can handle a bit of SMT rework, but I also don't really want to put the maybe still working (?) main board at risk if I don't have to?
Thanks for any advice!
Devin KN6PHZ?
|
Re: Get to know your dental hygienist!
#15 scalpel blades are perfect for removing solder mask from traces, and for cutting traces and shorts.??I prefer carbon steel over stainless, and non-sterile may or may not be cheaper.
73, Don N2VGU
|
Re: QCX WARC Party - January 2024
Hi Luc,
?????????? Did 13.00 ¨C 14.00 and 19.00 ¨C 20.00 both on 30 meters.? I was heard on the east coast of the states, Iceland, Finland, and many many stations in Europe, but did not hear a single reply.? Think I will miss the 0200-0300 session.?
Have a good evening 73¡¯s? Mike G0KCH
?
Sent from for Windows
?
toggle quoted message
Show quoted text
From: ON7DQ Luc
Sent: 15 January 2024 14:14
To: [email protected]
Subject: Re: [QRPLabs] QCX WARC Party - January 2024
?
My 1300Z session:
First on 30m (using my QCX Classic 20m) I worked the "regulars" PA0CMU, DK3UW and OK2BQN, then ... nothing.
With some trouble I could get through the pile up of a SOTA station OK/DL5AZZ/P.
Then went to 17m with my QCX Mini "15m". I got spotted all over Europe, and got two spots in US with 9 and 13 dB, but no replies.
73,
Luc ON7DQ?
|
Another thing to bear in mind is that not everybody can use a binocular microscope. If for example you have a significant strabismus(?) aka an alternating divergent squint you might be limited to one eye at a time. Something displaying on a screen as has been discussed would seem to be a better choice.
John F5VLF
toggle quoted message
Show quoted text
On 15 Jan 2024, at 22:11, Brock VA7AV < brock@...> wrote:
I picked up a Pluggable USB microscope to try. Very inexpensive but does a pretty decent job. The problem is always coordinating your hand movements through what you are watching them with. The binocular microscope that was linked would be ideal for that reason. However, by placing my monitor behind what I'm working on, I've been able to manage. I put the camera on a Gorillapod tripod, which I already had, to get good stability.
I've thought about trying one of those huge magnifying glasses on a flexible arm with built-in ring light (like used by crocheters and similar), but haven't yet.?
73, Brock VA7AV?
|
Re: QSX: I'd like to purchase a fully assembled & tested QSX
NO WAY !!! THAR SHE BLOWS !!!
73,
Bill, N4QA/4
|
I picked up a Pluggable USB microscope to try. Very inexpensive but does a pretty decent job. The problem is always coordinating your hand movements through what you are watching them with. The binocular microscope that was linked would be ideal for that reason. However, by placing my monitor behind what I'm working on, I've been able to manage. I put the camera on a Gorillapod tripod, which I already had, to get good stability.
I've thought about trying one of those huge magnifying glasses on a flexible arm with built-in ring light (like used by crocheters and similar), but haven't yet.?
73, Brock VA7AV?
|
Lee W0VT (W5DRC?) wrote¡ I'm thinking of buying one of those electronic magnifiers with an attached 7-9" screen¡ I had one with (I think) a smaller screen than that. It definitely worked, but I returned it because pressing the button on it to take still pics shook it so much that they were blurry and unusable. I will probably get another one one day but I¡¯ll be a bit more choosy. -- 73 Keith VE7GDH
|
Hi Evan,
thanks for your help again.
Am 15.01.24 um 19:34 schrieb Evan Hand:
The next thing to test is the pins 10, 11, 12, and 13 of IC402.?
The selected filter should be 2.5 volts, and the others should be
close to zero.
I get the following:
PIN
|
10
|
11
|
12
|
13
|
BPF-Config
|
80m
|
|
|
|
X
|
3
|
60m
|
|
|
|
X
|
3
|
40m
|
|
|
|
X
|
3
|
30m
|
|
|
X
|
|
2
|
20m
|
|
X
|
|
|
1
|
That looks fine to me. Or am I mistaken?
If the above
checks, test that Q508 is turned on while receiving.? The source
and drain should be close to zero volts.
Not so sure on this one: Drain 0.64V, Source 0.07V, Gate 0.69V -
no matter what band I select. - Is this maybe the suspect?
Strange, as there was no re-soldering in that vicinity.
The last check
would be testing the low-pass filter diodes and toroid
connections.? Only the two for the selected band filter should be
one of the six diodes, measuring close to zero volts on the banded
(cathode) side of the diodes.? The other diodes should be close to
the input voltage to the QMX.? Both toroids in the LPF connection
are required to get the diode to switch on.
This looks also good to me:
80m: D508 & 511 0V
60m & 40m: D509 & 512 0V
30m & 20m: D510 & 513 0V
I am discounting
the quadrature sector and T401 based on the discrimination of the
sideband, though at a low level.? That would not happen if there
were an issue with the I/Q processing through the audio codec.
OK.
Others in the group
may have different ideas and may be better at isolating the
problem.
... yes please. Any ideas welcome :).
But my interpretation would be a fried Q508 ... so change one
BSS123 MOSFET.
Please confirm this diagnosis.
Thanks again and Vy73
Stefan.
--
Stefan U. Hegner <db4st@...>
* * *
DB4ST --- German Ham Radio Station
D-32584 L?hne ----- Locator JO42IE
* * *
GPG-Key | C3CC 23A4 FBA8 622B 48AE
F-Print | 4F19 D0EE E39E ABDC 2BCE
|
Re: QSX: I'd like to purchase a fully assembled & tested QSX
On Mon, Jan 15, 2024 at 06:25 PM, Bill wrote:
Should be safe for most things!
? LOL. Stabilized for 5v MCU's I presume ? -- - 73 de Andy -
|
Thanks Alan.
I read and understood the manual with regard to the jumper install but misread the pcb layout for the resistor.?
I will move the one leg of resistor to the top hole leaving 2 unused jumper holes open under the resistor.?
--
regards,
Bryan, N0LUF
|
Re: QMX no Rx after a few days of operation
I replaced IC402 and added the diode. Now all seems to be ok, thanks for your advise.
73 Hans-Wilhelm DG8YBJ
|
My eyes are not what they used to be. I'm thinking of buying one of
those electronic magnifiers with an attached 7-9" screen or
something close to that size. ? Can anyone give me some insight as
to what I should buy?? (I'll spend up to $175 if required.)? I've
been using a lighted magnifying glass for vision impaired and that
works OK if I don't fog it up but keeping proper distance is a
pain.? I thought maybe an electronic one might work better.?? My
eyesight is just typical old guy eye sight.
Lee, w0vt
|
Re: Get to know your dental hygienist!
I also ask for old burrs for my Dremel. There are still plenty sharp when the dentist can't use them.
--
Colin - K6JTH?
|
Re: Get to know your dental hygienist!
Careful with that scaler Eugene (Pink Floyd).
--
- 73 de Andy -
|
Re: Get to know your dental hygienist!
I second that. Got some myself from my dentist. VERY useful.
toggle quoted message
Show quoted text
On Jan 15, 2024, at 14:07, Rick Williams - VE7TK via < ve7tk@...> wrote:
I recently completed my QMX 20 - 10m radio. The construction went very well. It went so well in part because of my wonderful dental hygienist!
On a visit last fall for my annual cleaning I spoke to my hygienist about building some new electronics. I was complaining about the detailed work involved especially ensuring that there were no shorts between component parts. She nodded politely and the cleaning continued.
As we were finishing up she disappeared and returned with some dental tools in a sterilized package. She handed them to me and informed me that these were past their useful lifetime and perhaps they might be of use to me!
EUREKA!! These tools are absolutely perfect for scraping at the area between traces on the QMX. With some magnification you can quickly evaluate if that "glob" is a solder bridge or just some flux! I also found them useful for compressing or spreading out coils on the LPF toroids. Definitely a useful addition in the shack!
Get to know your hygienist ...
--
73, Rick
VE7TK
Website:
<PXL_20240115_194138953.jpg>
|
Get to know your dental hygienist!
I recently completed my QMX 20 - 10m radio. The construction went very well. It went so well in part because of my wonderful dental hygienist!
On a visit last fall for my annual cleaning I spoke to my hygienist about building some new electronics. I was complaining about the detailed work involved especially ensuring that there were no shorts between component parts. She nodded politely and the cleaning continued.
As we were finishing up she disappeared and returned with some dental tools in a sterilized package. She handed them to me and informed me that these were past their useful lifetime and perhaps they might be of use to me!
EUREKA!! These tools are absolutely perfect for scraping at the area between traces on the QMX. With some magnification you can quickly evaluate if that "glob" is a solder bridge or just some flux! I also found them useful for compressing or spreading out coils on the LPF toroids. Definitely a useful addition in the shack!
Get to know your hygienist ...
--
73, Rick
VE7TK
Website:
|
Re: QSX: I'd like to purchase a fully assembled & tested QSX
On Mon, Jan 15, 2024 at 02:29 PM, Bill wrote:
You mean QS SEX???
Uh oh, I've got visions of users at Hamfests dressed as QRP Labs products now. There's a similar related medical condition for that - Don't forget to remove your callsign badges folks ;-)))) ? -- - 73 de Andy -
|
Donald S Brant Jr
Bill, N4QA/QRP
Colin Kaminski
Rick Williams - VE7TK