I completed the QMX kit build and got everything up and running OK including making some initial FT8 QSOs. I built for 12V and have been running on 12V from my regulated (but not current limited) bench PSU with a total power on time so far of about 2 hours.
So today I was exploring the menus for beacon mode, when the magic smoke suddenly escaped - QMX was not transmitting at the time It looks like the C107/Q108 failures reported by others here
I think the best approach here will be to rig up linear 3.3/5V supplies (I have plenty of linear regulators to hand) to test the main boards for collateral damage before repairing the PSU board
On Aug 23, 2023, at 7:42 AM, Bryan Curl <bc3910@...> wrote:
Time.is is good. Ive had issues using built in time sources for updating the pc time automatically and wondered if a lagging wi-fi connection could have caused some delay. Sometimes it works and others not so much. But setting manually to time.is has always worked for perfect ft-8 timing. -- regards, Bryan, N0LUF
Time.is is good. Ive had issues using built in time sources for updating the pc time automatically and wondered if a lagging wi-fi connection could have caused some delay. Sometimes it works and others not so much. But setting manually to time.is has always worked for perfect ft-8 timing. -- regards, Bryan, N0LUF
Trying to setup JS8 on my QDX. (all works fine on FT8) TX works OK but am getting no indication of receive audio on the left hand level meter (nothing on the waterfall)
Using latest version of QDX with latest version of JS8Call on a Mac M1. Both AUDIO settings are set to QDX and RADIO is set to TS480.? CAT test is green.
Friends , Romanos,? ?Gentlemens? ---? lend? me one buck I can do it for you because that's the Ebay price for the Tda7052AT?
BUT it , the design,? works ONLY with the AT variant ,? not the bare 7052 because the latter has no mute input.?
Here's the cct that the? MST 2 from Australia used to? use - a fine cct but Ozqrp shut down when the owner , Leon , retired.
Note that the? LM08 psu is critical? . This device will NOT withstand 12V.? ?the Audio? is 500% better than the crap you will get out of an LM386 cct no wining noises , no biasing in favour of the? HF elements of the AF band because of capacitive coupling, because there ain't any.? Note how there is? provision for Tx on muting.? this damned cct has everything.
Fly in ointment - the chip is obsolescent.? BUT it rides at night on Ebay and varous SE asian sources . Futurlec.com does not list it but often he can get not too hard parts if you pester him.? Don't buy? one unless they are rationed get two or three.? Note that i adding AGC to an existing say LM386 cct you may have to just abandond what is there and make up a replacement amp on a piece of veroboard.? Don't forget the support holes.
On Wed, Aug 23, 2023 at 10:20?AM KEN G4APB <lfoofui.nbz42@...> wrote:
QSX all-band all-mode transceiver
?
Details
?Created: 16 August 2018
?Last Updated: 01 September 2020
Any updates Hans? Do you see the new QMX with SSB replacing this or as a stepping stone?....A bit like deciding to go to Mars but stopping off on the moon on the way huh? best 73 Ken G4APB
Any updates Hans? Do you see the new QMX with SSB replacing this or as a stepping stone?....A bit like deciding to go to Mars but stopping off on the moon on the way huh? best 73 Ken G4APB
Re: #qmx Bringing up QMX, Nothing in display but terminal works, shutdown press does not
#qmx
Paul, I had a similar issue, which turned out to be pin 3 of the display board making contact with the inductor on the power supply board above it. /g/QRPLabs/message/107812
Hot air is a good investment. Cheap hot air stations are fine for hobbyist use. I spent less that $50 for a three-channel variant of the usual single 858D stations. Three-channel is a bit of a luxury, which I do enjoy, but single channel will get the job done fine, and they can be had for under $40. Here's one Comes with nozzles and tweezers.
I used 2 schottky diodes in antiparallell on my QCX-mini.? It does save your ears from audioshock!? It does not influence audio quality under normal operation, since the diodes are not clipping the waveform.? But you still have large variations in audio level when tuning across the band.? When the AGC-Boards became available I installed one of them, and it makes a world of difference! Now you can comfortably tune the bands
On Wed, Aug 23, 2023 at 12:47?AM Mike Black via <mdblack98=[email protected]> wrote:
That's a firmware bug -- apparently must be removing the "," but not the "." or such from the RIT/XIT frequency.
Mike W9MDB
On Tuesday, August 22, 2023 at 04:28:33 PM CDT, Chris <chris.rowland@...> wrote:
I am that user.
I think I've got it.? I changed the delimiter to '.' instead of
',' When I did this the additional '.' appeared in the IF;
Response.
Log file from QMX attached.
Chris, G5CTH
On 22/08/2023 14:45, Mike Black via
wrote:
Have a user that's filed a bug report on QMX
firmware 1_09
There's a period in the response which seems to
be wrong and moves the rest of the data 1-byte so '2' which is
the mode is being recognized as the FR/FT result indicating
MEM VFO.
Sorry, I forgot ... Hans / QRP Labs will be offering the separately.? $10.? They won't be available for a few more weeks though.? Probably in manufacturing.
You can fix your board sooner than that with a new Q103 (big) transistor, and you'll have learned some good new techniques.? Be aware that Q103 has a large copper pad underneath it.? Probably for heat dissipation.? It will take a fair amount of heat to get that solder joint to release.? Again, Mr SolderFix' formed wire technique should do it just fine.? Personally I'd go with the low-temp alloy;? I like to use as little heat as possible for repair operations.? Be gentle on everything and you won't turn a small problem into a big problem; lifting pads for example.
Some components like large ICs have large copper pads underneath them, completely inaccessible to soldering iron techniques.? If you have to repair one of those some day, you'll have to use wide area heat.? The easiest, cost-efficient approach would be to use a heat gun.? I love my heat gun ... everybody who gets a heat gun loves it.? You do have to practice with it though!? Watch a bunch of YouTube videos so you know how not to blow nearby components away!? And practice, practice, practice on junk boards before you attempt your intended repair. Got an old dead cell phone?? Rip it open and take parts off the board one at a time.?Finesse is everything with a heat gun.
Sorry that you busted your transistor.? That's been mentioned in other topics; components can't take much physical stress. But you can install a new transistor without too much trouble.? Read on.
For others with the same situation, there are gentler ways to solve the problem so you don't damage either transistor.
Recommended.? Review the video; Mr SolderFix shows very workable techniques for removing components.? I would focus on moving the small transistor, Q104.? You should be able to move the small transistor using his technique of a form-fitted piece of copper wire, which allows you to melt all three legs' solder joints at the same time.? I'll suggest getting all 3 joints melted, then move the small transistor away from its pads toward the edge of the board, and remove the heat-transfer wire.? Then go about soldering the transistor back onto its pads, leaving a gap in between it and the large transistor Q103.
You can accomplish the same goal of removing Q104 (or Q103 if you prefer) using low temperature desoldering alloy.? I have done this on QFP chips, Quad Flat Pack, 32 pins, so I know it can work on a 3-pin device like Q103 or Q104.? The alloy is sold under brand names and on Amazon. I like low-temp desoldering alloy quite a lot.? Just clean up all the weird alloy from the transistor legs and the board pads, using desoldering braid and flux, before you reinstall the transistor.
Also pay attention to Mr SolderFix' technique of removing solder from through-holes.? You'll need that technique some day.? Desoldering braid and liquid flux and a little finesse --? which this guy shows you -- gets it done.? His YouTube channel is really, really good and informative.
I purchased an air gun for this very reason! Applied the airgun
and Q103 fell right off the board. I ended up soldering it back
in, with my iron.
As a matter of interest, removing Q103 did NOT remove the solder
bridge! But I could see it plainly and get to it, at least. Just
moving Q103 would not have fixed the problem I had!
I would think the best "iron only" approach would be to use
solder wick to remove as much solder as possible from the lead end
of Q103, maybe lift them off the board just a bit? Be very
judicious, many reports of breaking these leads!
Then flux and heat the tab of Q103, melt the solder there, and
lift it gently up--just a bit. Too much will lift the connections
on the other end of Q103 (I think!). That may remove Q103
entirely, so you can work in the area freely (good for you!)
Place Q103 back, tack it in place, taking care to keep away from
Q104's gate tab. Solder the other lead, and resolder the tab.
(I found putting Q103 back to be quite easy. The way I removed it
was surprising to me, I didn't expect it to leap off the board!)
So my QMX board showed up with the Q103/Q104 short and I figured I
would try to fix that before starting on the actual build. Has
anyone successfully done this with a soldering iron, as opposed to
a hot air gun? I've never done any SMD work, but figured Q103 is
big, so maybe I can heat up the large pad and nudge it over, but
it wouldn't budge with increasingly aggressive heating. I decided
to try and the gate and source pins first, and ... Q103 shattered
at the gate pin.
I know this thing is very much in development, but it's
frustrating to have a defect like this on a board intended for kit
builders. Maybe Hans can offer replacement power boards for some
nominal fee since these have been causing so many problems for
people? For now I'm setting this project aside.
#qmx Bringing up QMX, Nothing in display but terminal works, shutdown press does not
#qmx
Won't work well because you are requiring heat flux through steel (the bolt) to get to the Cu .
What you want is a thick Penny? (buy one from a coin dealer for example)? , put it on grinding paper say P80 grit? backed? by a wet? glass plate or kit bench and flatten it and then use P200 to get? smooth surface then Drill precisely in ctr using? a ctr finder if you have one ( or scribe against two chords ) or mound in a lathe chuck to find the ctr .? Cu has amazing density cw with what most people think - It's about 70% of steel. this makes it particularly good at absorbing the pulses of heat it would typically get in voice SSB operation.? (but not so good for? continuous digital modes). Brass is an unacceptable substitute .?
The big problem is the rounded back of the BS? 170? cases - potentially you can lap them to a small rectangle say 1.6mm across x the TO92 case height? by hand and a jig? for improved HT but if you have the soldered on the PCB then you are sod out of luck unless you want to do a pull and resolder job.
Obviously you? can go for? a gold plate solution where you solder small Cu fins got from material you can buy as copper shim from machinist supply houses on to the coin with? a? VERY hot/powerful Soldering iron on to the top? of the Cu coin.? The shim is used for stopping marking on workpieces held very tightly in lathe chucks and the like.?
Karl
UPNORTHOF48 :
Timothy Fidler
Paul - AI7JR