|
Hi, have started on my QMX+ build kit and started on chapter "2.5 Install all the ceramic capacitors"
Have had an "item count" that I have them all but find out that I have two that are not listed in the manual.
15J I have one too many of, and I can't find 33K in the component list.
After distributing all components to the correct location (paper sheet), I am then missing C402 which should be marked 330 or 33J and then I am missing C542 which should be marked 680 or 68J
Have put everything together on a sheet and triple checked values. Can any of the ones I can't find be used or do I have to get what is missing?
--
Lasse
|
Lasse The capacitor marked 33K is fine for the missing 33J. Ran into the same problem with that one and got the OK to use it in my QMX build from Hans. The K is just a tighter tolerance component.?
You will definitely need the 68.?
Try looking carefully inside mechanical components, the wire bundles, and baggies that things came in. Tiny things can hide in the oddest places.
If it's just not there, you could: -- contact QRPLabs order follow up ----? perhaps a week to 10 days to get one ?
-- order from Mouser? ---- cheaper shipping than Digikey but Digi Key shipping perhaps faster?
-- try Amazon ---- might have to get an assortment that includes one. If you are a Prime Member then free quickish shipping
-- try eBay
Not sure of your QTH. If not in the USA then hopefully others in the group can steer you in the right direction for your location.?
Or, another builder may be able to get one to you pretty quick.
Build carefully. Mind the caution to be sure to get enough heat on solder joints that go to the ground planes. The QM's have 6 layer boards with several ground planes and can sink heat extremely well.?
Best of luck. Great radios!
GREG KI4NVX?
On Sun, Nov 17, 2024 at 8:56 AM, Lasse via groups.io <div.tt14@...> wrote: Hi, have started on my QMX+ build kit and started on chapter "2.5 Install all the ceramic capacitors"
Have had an "item count" that I have them all but find out that I have two that are not listed in the manual.
15J I have one too many of, and I can't find 33K in the component list.
After distributing all components to the correct location (paper sheet), I am then missing C402 which should be marked 330 or 33J and then I am missing C542 which should be marked 680 or 68J
Have put everything together on a sheet and triple checked values. Can any of the ones I can't find be used or do I have to get what is missing?
--
Lasse
|
?
See that thread about the 33K marked one.?
?
Looks like you may be missing the 680pf one, though. I just ordered a 680pf from Mouser recently for a 160m QDX-M build, so happy to share a part # if needed.
You could build the QMX+ and just leave the 160m 680 pf out for now.... as 160m receive doesn't function yet anyway.
?
-Nate?
N8BTR
|
Great point Nate!
No need to halt assembly :)
On Sun, Nov 17, 2024 at 9:44 AM, natereik via groups.io <natereik@...> wrote:
?
See that thread about the 33K marked one.?
?
Looks like you may be missing the 680pf one, though. I just ordered a 680pf from Mouser recently for a 160m QDX-M build, so happy to share a part # if needed.
You could build the QMX+ and just leave the 160m 680 pf out for now.... as 160m receive doesn't function yet anyway.
?
-Nate?
N8BTRe
|
Thank you very much everyone for the useful information :-)
Not an expert in electronics, just think it's fun to build things yourself.
Found a box on ebay with lots of different capacitors, so I'll continue building in anticipation of the one I'm missing
?
--
Lasse / LA5PPA
?
|
?
?
Here's a couple different web pages describing how capacitors get marked these days.
?
From that, 33K is a 33pf cap with a 10% tolerance, and 33J is a 33pf cap with a 5% tolerance.
Apparently they made a substitution due to the 5% parts being unavailable.
C402 gets used in the receiver bandpass filter for 17 and 15 meters, so it covers
at least 18 through 21 MHz and probably more.? I'm confident a 10% part would be fine there.
Can be verified with a sweep of the filters after the rig is completed using the tests
described in the assembly manual.
?
That 15J cap is a 15pf cap, but C542 needs a 68pf cap.?
C542 is used in the transmit LPF for the 6M band, without that cap it will
probably receive well enough on 6M but it won't transmit very well.??
You could probably live forever without C542 if like me you don't have an antenna for 6m.
To replace it, look for a disc ceramic cap with radial leads, 5% (or 10%) tolerance,
voltage rating of 100 Volts or more, temperature stability of NP0 or C0G,
and lead spacing of 2.5mm.? Here's a selection on digikey:
https://www.digikey.com/en/products/filter/ceramic-capacitors/68-pf/60?s=N4IgjCBcoMxaBjKAzAhgGwM4FMA0IB7KAbRACYBWABjnzBgBYqQBdfABwBcoQBlTgE4BLAHYBzEAF86DeCCSQ0WPIRIgAbAE51ZTSDpUq6gOwQZVABwML%2B8BWO6zd4zDBlbYC2QuXb17wwUrBzckHyCohLSGnrQ8igYOPhEkKQMYJ6axsEgXDz8wuJS%2BNQ2cQpKSaqp4DDG6R4MZAxwbLmh4YVR%2BGRUDLGICcr4AG4iUIIArioppOoWAATsAGI5eWEAqiJCnADyyACy2KiYkwLYxSAAtO7lEwLTyWpB%2BHosktHqckIAJjxXYCoTnWIFsnAAnuwLmETkgPkA
?
Jerry, KE7ER
?
?
On Sun, Nov 17, 2024 at 05:56 AM, Lasse wrote:
Hi, have started on my QMX+ build kit and started on chapter "2.5 Install all the ceramic capacitors"
Have had an "item count" that I have them all but find out that I have two that are not listed in the manual.
15J I have one too many of, and I can't find 33K in the component list.
After distributing all components to the correct location (paper sheet), I am then missing C402 which should be marked 330 or 33J and then I am missing C542 which should be marked 680 or 68J
Have put everything together on a sheet and triple checked values. Can any of the ones I can't find be used or do I have to get what is missing?
|
On Sun, Nov 17, 2024 at 09:12 AM, Jerry Gaffke wrote:
C542 needs a 68pf cap.?
C542 is used in the transmit LPF for the 6M band, without that cap it will
probably receive well enough on 6M but it won't transmit very well.?
?
Oops, sorry Lasse, Jerry's right, it's the 68 that's missing, not a 680. But still, you can carry on with the other bands.?
To Jerry's point, it is important that you get the right type of capacitor for this...make sure your lot from ebay is the right type.?
?
-Nate
N8BTR
|
Lasse,
This is the time to use Google for capacitor identification information. Print out every one that you find and keep handy. You will need it if you continue with this hobby. ?Then step #2¡¡ get one of the low cost capacitor checking units on line so you can check each capacitor you are just installing to make sure it¡¯s the correct one¡ with that device you will have to learn the difference between farad, microfarad, picofarad, etc¡. as the list of materials may list it one way and your testing device may show it another way¡. It will confuse you at first but eventually you will get it straight (how many zeros between micro and pico) in your head. ?And lastly get a box set of COG caps as you will need one or two occasionally when there is one missing from your new kit.
Next, enjoy the build. ?I check each resistor, cap, toroid before soldering in place. It¡¯s easier that way when your new radio kit has issues than to misread a part and solder it in place on,y to have to remove it later. ?I still make mistakes but I read everything Hans has to print out before the build and that greatly reduces errors and improves my smile quotient when it works the first time.
Be the REASON someone smiles today.
Dave K8WPE
toggle quoted message
Show quoted text
On Nov 17, 2024, at 8:56?AM, Lasse via groups.io <div.tt14@...> wrote:
? Hi, have started on my QMX+ build kit and started on chapter "2.5 Install all the ceramic capacitors"
Have had an "item count" that I have them all but find out that I have two that are not listed in the manual.
15J I have one too many of, and I can't find 33K in the component list.
After distributing all components to the correct location (paper sheet), I am then missing C402 which should be marked 330 or 33J and then I am missing C542 which should be marked 680 or 68J
Have put everything together on a sheet and triple checked values. Can any of the ones I can't find be used or do I have to get what is missing?
--
Lasse
|
|
|
Looking good. I started and finished building my QMX+ yesterday. The torroid winding is always a daunting task for me but I completed this one in record time.?
May all your magic smoke stay contained in the little electron capsules.?
Joshua
|
PROGRESS!
?
FB
?
GREG KI4NVX
?
|
On Sun, Nov 17, 2024 at 09:43 AM, Greg McCain wrote:
Mind the caution to be sure to get enough heat on solder joints that go to the ground planes. The QM's have 6 layer boards with several ground planes and can sink heat extremely well.?
It is likely that to obtain optimum results you may need to use a different tip, temperature or both for the grounded end of some components.? I do rework/prototyping for my clients and I will often have 2 irons in play.
73, Don N2VGU
|
On Sun, Nov 17, 2024 at 09:57 AM, Lasse wrote:
so I'll continue building in anticipation of the one I'm missing
Don't forget to document the part shortage, so that you do not forget later and wonder why 160 meters doesn't work......
73, Don N2VGU
|
I suppose the ideal might be to use exactly the right iron on each joint,
but hardly seems worth the trouble.?
It is a good idea to have two irons if you happen to have two hands,
makes it easy to pluck surface mount resistor, cap or coil off the board.
?
I have this $17 100W iron: ?
Set it to around 430C, turning it down to 300C when not using it for a few minutes
so it doesn't burn up the tip.? Worked fine, including on all the grounds.
Used the conical tip with the flat end, second from the left in their photo.
The conical shape gets heat to the end quickly, the flat has enough
surface area to dump a lot of heat into the joint quickly.
At 100W it might be overkill for the QMX but that's not a drawback since it is
thermostatically controlled and the tip maintains a constant temperature.
Did fine on all my QMX joints.?
?
I also have Weller and Hakko soldering equipment rescued from dumpsters,
when those fail it's often something like an intermittent power cord.
?
I do tend to go for high heat, I can be done and out of there before damage occurs,
a lower heat tip means more time at the joint and more time for heat to move elsewhere.
Plastic parts like phone jacks and power connectors seem more likely
to melt on me when I use a low tip temperature and spend too long soldering.
A Q-tip dipped in alcohol or water can be used to quickly cool a heat sensitive part
once the soldering is done.
?
The paranoid might wrap some bare copper wire around the barrel near the handle,?
solder the far end of that wire to their board.? Ensures the iron doesn't blow a part
due to a bit of coupling from the AC line.? It is $17 after all.
?
For heat conducting grounds into half inch steel plate, I use this one:
?
Jerry, KE7ER
?
On Sun, Nov 17, 2024 at 08:37 AM, Donald S Brant Jr wrote:
On Sun, Nov 17, 2024 at 09:43 AM, Greg McCain wrote:
Mind the caution to be sure to get enough heat on solder joints that go to the ground planes. The QM's have 6 layer boards with several ground planes and can sink heat extremely well.?
It is likely that to obtain optimum results you may need to use a different tip, temperature or both for the grounded end of some components.? I do rework/prototyping for my clients and I will often have 2 irons in play.
73, Don N2VGU
|
I got the C542/68pf cap from a UK seller on ebay so it's hopefully here within a week or two.
Toroid winding is the next step :-)
|
Almost done, waiting for the C542 before smoke test
|
Lasse,
?
Looks good!
If I were you, I'd power it up without C542.
Only thing that C542 would affect is transmitting on 6 meters.
?
Start out with a reduced voltage,? rig should still work down as low as 7 Volts.
Power supply should also be current limited at first power up.
Should never draw more than a couple hundred mA until you attempt to transmit.
A 9v alkaline transistor radio battery is inherently current limited, should last?
for most of a day using the receiver, and will allow transmitting for most of an hour.
?
Even an attempt at transmitting on 6 meters won't do any damage,
especially at a reduced power supply voltage.
Power out when transmitting will be reduced by the lower voltage.
?
Jerry, KE7ER
?
?
On Thu, Nov 21, 2024 at 09:42 AM, Lasse wrote:
Almost done, waiting for the C542 before smoke test
|
Thanks Jerry and you know what ?...? it did pass the smoke test :-)
Been on for over an hour at 12v / 0,02amp (started at 7v and slowly up to 12v)
Will have to see if I can get a wire out the window tomorrow to test if it picks up anything. (live in an antenna-prohibited building)
--
Lasse
|
Excellent!
From that display, the processor is working properly.
Let us know how the receiver check goes.
?
Next step might be running the diagonstics?through a USB cable
to a host computer as described in the operations manual.
You will need a 50 ohm dummy load for the transmitter checks,
and a bit more current from that power supply.
?
Jerry, KE7ER
?
On Thu, Nov 28, 2024 at 12:32 PM, Lasse wrote:
Thanks Jerry and you know what ?...? it did pass the smoke test :-)
Been on for over an hour at 12v / 0,02amp (started at 7v and slowly up to 12v)
Will have to see if I can get a wire out the window tomorrow to test if it picks up anything. (live in an antenna-prohibited building)
|
Hmm... completely silent on reception except for some loud beeps on some bands,
A short TX on 20m in a dummy load with a qrp watt meter in between shows no TX and no changes in amp use
CAT control seems to work via USB-C, connected it to WSJTx and it works on everything the same as my QDX.
I'll have to take it out of the box and check if I can see any visual defects first
?
--
Lasse
?
|
David Wilcox K8WPE
Joshua KJ7LVZ
Donald S Brant Jr