Re: Removing flux. Is it necessary? Yes/No
I use alcohol and a cheap Harbor Freight Ultrasonic cleaner.?? Awesome.
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Re: Removing flux. Is it necessary? Yes/No
Certain solder described as containing "no-clean" flux will leave a residue that even alcohol pads won't touch,? I made the error of purchasing a pound of Kester 63/37 with a non-rosin flux:
I have since purchased
The Kester 44 is a solder I have used for decades.? Activated rosin core, remains clean up just fine with alcohol.
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Re: qmx with tiny lcd display
Hi Wei,
good news. That gives me hope that I will find a suitable one. I think I need to order more and try them out. Yes, that's definitely the case with the eyes.
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Re: 180pf (181) Capacitor Needed
Use the search bar and type in the value of the capacitor. Then skinny down using the filters on the search results especially the form factor that Hans supplies in his detailed parts lists. For instance, 2.2u SMD 0603.?
For most ICs just type in the chip designator from Hans parts lists.
On Sat, Sep 21, 2024 at 3:51 PM, Bill Jobes via groups.io <jobes@...> wrote: Thanks, Greg.? I had already visited both sites and found their search systems designed for PhD EE types, not a hobbyist like me !??
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If you or anyone reading this has a direct like to a supplier of the exact 180p 181 caps used in these kits, please reply.
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Hans, if you see this, can you help ??
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More sources of transverters and ancillary items:
? I have worked with the founder and current owner, both great hams.
Transverter? manufacturing and sales have been picked up by
Being US-based they may be light on 70MHz stuff but it worth looking into.
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Jim, W6PQL has a lot of useful items, like a relay sequencer, that you might require: ?
I don't see any lower-band transverters on his site but it is worth an inquiry, he communicates well.
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Good luck.
73, Don N2VGU
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Have a look at Paul Wade W1GHZ's site, here is a link to the Transverters page: ?
Paul is a former MSC co-worker and technically and practically very astute and very much into helping other hams.? I learned a lot of solid, practical stuff from him early in my career.
His QST columns and other writings are worthwhile reading.
RF/microwave MMICs really revolutionized the technology of transverter-making, with their stable, predictable properties.?
Paul's innovative PCB filter designs and plumbing fitting filter realizations are another key to consistent results.
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P.S.? I just read that one of the 10GHz MMICs which were frequently used in his designs has gone EOL.? Hopefully a suitable replacement can be found.
Good luck and 73, Don N2VGU
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Re: qmx with tiny lcd display
Hi Stefan,
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Not on a QMX, but on a U3, I had swapped standard 1602 with a mini 1602, it worked fine. I believe as long as it says 1602, they are compatible.
But smaller size may put some stress on your eyes. It's OK for U3 because we don't look at its screen that much.
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Hope this help.
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73, Wei
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Has anyone used a KX3 with the QRP Labs 59 watt amp? ?If so, how did you do it?
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Re: 180pf (181) Capacitor Needed
Bill, are you talking about a leaded 180pf capacitor, I assume??
If so, I ordered this part recently for a modified QDX build:
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"All QRP Labs kits use low loss multi-layer ceramic NP0 capacitors for all capacitance values below 5nF. This includes all the LPF and BPF kit capacitors for HF bands. These capacitors are also sometimes known as C0G, CC4 or Class-I dielectric types. The voltage rating of these capacitors is adequate for up to 10W. "
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So based on that, and what I've seen in the kits, a 50V, 2.5mm lead spacing C0G / NP0 Capacitor with a 5% tolerance is appropriate for replacement. Vishay is a good brand, in my opinion. You should see their strain gauge parts!
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-Nate
N8BTR
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A new chat has been created:
Just finished my 2nd QMX and made first QSOs
I guess it's not normal, that they have such a different current consuption
would you advice to exchange the BS170 in the QMX 20-10m?
thanks for any advice
HB9BAB Jürg
By:
HB9BAB@...
View/Join This Chat
Do not reply to this message to post to the chat. You can participate in chats only through the group's website.
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Re: 180pf (181) Capacitor Needed
Thanks, Greg.? I had already visited both sites and found their search systems designed for PhD EE types, not a hobbyist like me !??
?
If you or anyone reading this has a direct like to a supplier of the exact 180p 181 caps used in these kits, please reply.
?
Hans, if you see this, can you help ??
?
?
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HB9BAB@... added the photo album
HB9BAB
: QMX
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Re: Removing flux. Is it necessary? Yes/No
I use "acid brushes" with the bristles cut down to about half length to scrub the board while it is wet with solvent.? Saves time and effort when removing flux residue.
73, Don N2VGU?
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Thanks for all info, I appreciate that, and I will try to replace the si5351.?
73
Alf, la1zm
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There's an article in the wiki outlining a series of tests on the SMPS modules independently of the main board, it might help to isolate the problems.
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Or remove the SMPS boards and try supplying regulated and current limited power to the main board, start with 3.3V and see if the processor is alive using Putty.
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Chris, G5CTH
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Re: QMX+ bias current + output power fluctuating
I too had a problem with output fluctuation.
I found that with a 9V supply the problem went away.
I must have made a mistake when wrapping the T501.
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qmx with tiny lcd display
Has anyone ever tried to install a smaller LCD display in a qmx. Is there any experience with this?
Which one can i use?
like this one
https://a.aliexpress.com/_Ew3iRHL
73' de dl9tx
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Re: Removing flux. Is it necessary? Yes/No
On Sat, Sep 21, 2024 at 11:29 AM, Tony Scaminaci wrote:
Second, it makes looking for solder bridges, shorts, and cold solder points much easier.
The cleaning process will direct your attention to each area, kind of like hand-washing your car will allow you to find those little dings and scratches you would never have noticed if using the car wash.
Extra style points for cleaning and inspecting under 8X-10X binocular magnification.
73, Don N2VGU
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On Sat, Sep 21, 2024 at 08:19 AM, Alan G4ZFQ wrote:
Others have cut the IC pins with a Dremel-type tool or even with a scalpel.
A scalpel blade, specifically a #15 blade, applied with a rocking motion adjacent to the IC body, will slice cleanly through the leads without putting undue stress on the PCB lands.
Then merely individually heat and pluck off the leads, clean up the lands and you are ready to reinstall.
Good luck and 73, Don N2VGU
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Re: Removing flux. Is it necessary? Yes/No
I took Jeff Moore's advice and bought a pint of 99% isopropyl alcohol from Amazon ( about $9). Much better than even 91%.?
A little goes a long way. Really cleans quick and leaves little or no smeary residue.
On Sat, Sep 21, 2024 at 12:40 PM, Bruce Akhurst <bruce@...> wrote: 'Flux rarely causes a problem during the warranty period - especially the no-clean stuff'
But years-on in certain circumstances of temperature and humidity it can become a problem for RF and power circuitry?
I generally clean it off.? ?The no clean fluxes may require a specific cleaner like ECSP or FLU FluxClene? (both of which can often be ordered with a handy Brush) but many fluxes come off with just Isopropyl Alcohol
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Mark K9TR
Donald S Brant Jr