开云体育

Sorry to do it this way... -- 73 Karl KI4ZUQ

The QMX boards could be tested with some sort of bed of nails test fixture that provided the appropriate test signals for IC403 couldn't they? Use the CLK2 signal attenuated by R513 with a suitable

Those connections, (pin 9 ic 402 and pin 7/9 ic 403) are for the trifilar toroid. Supplied voltage is from the VCC. I get 5v at R401 with 2.6v drop across the resistor and approx 2.3 v (the

I understood that; you are handling it before it hits customers for everything except the QMX, however even you having to deal with a 15% failure rate on a component is nuts (for you to have to deal

Hi Karl I'll investigate now and contact you off-list about this. 73 Hans G0UPL http://qrp-labs.com https://buymeacoffee.com/g0upl [email protected]> wrote:

dr operators, Just finished the qmx plus. Build for9 volts and try with 8 v initially. When i connect the usb for fw i get the notice from my mac mini m2 that the usb port uses too much power and

Just had some civilian drop off a large box destined to Brian Churchwell 350 N Main St Ste 7 Unit 856 Wharton, NJ 07885 United States/AMERIKA Tel 8584127789 Mailed 04 June 2024? Customs

meant to say pin#5 on IC408 wrote:

I made some checks of the following as instructed: IC408 pin# only has 2.5v. (idle receive) IC402 pin#9 is 0v, IC403 pin#7 is 0v, pin#9 is 0v C402 pin#1 0v and pin#3 0v. I may have a problem here.

Hi Thomas, nice to see you here! Dou you remember? You once gave me the name "Papa Joe" on DB0EL. Happy new year and lots of fun with the QMX! 73 Peter DL4PJ

sorry, line 1) has a few words that were supposed to go to line 2). wrote:

Thank you Ludwig!! And a happy new year to you and your family. I actually just saw this now. Lol, I got some time this morning. I tried again to track down a problem in the receive path. This is what

Evan: The BS170 breakdown voltage actually increases with temperature. Before wasting too much time on marginal thermal improvement you should measure the thermal increase with key down.? Many VOMs

Hi all HNY! I was wondering if there had been any further investigation into this one or whether it's a matter of either accepting the noise or fitting a toggle switch (the latter is something I'm

To be clear again: I'm saying 15% of the batch of 1000 QMX+ Rev 2 PCBs was rejected during our testing here. The percentage of Rev 2 QMX+ with faulty PCM1804 that reach actual kit builders should be

Yes, remarkable that the PCM1804 saga continues. I built 4 QMX and one QMX+. Only one had an 1804 failure. First Rev 1 and Rev 3 (mini) had/have no failures. Second Rev 1 had SMPS (5V), then Mplx chip

A 15% failure rate for any semiconductor device is extremely high. Googling PCM1804 failures shows posts about high-level audio noise that randomly occurs and goes

Hi Mateusz, Gate input capacitance and output capacitance of any replacement transistor must be in the same neighborhood as the BS170. The closest match I’ve found is TN0110 which some here have

Hi Hans, Yes, the problem is very strange. In my case the PCM1804 worked almost correctly. The fault was only in the unequal amplitude of the I and Q signals. If I had not used the diagnostic tools

Wow - a 15% failure rate sounds exceedingly high. 73 -- Matt N3AR