On Sat, Aug 19, 2023 at 7:03?AM Frank <dc8fg@...> wrote:
Hi Chris,
seems, like everything is ok.
But there is still only very very low output on 30/20. So, for test I changed LPF-assignment for 30/20 to LPF 1 and there at least I could see a much stronger signal on 30 but very low on 20 (ok, the attenuation ist for this bands unsuitable). Therefore, there must be an bug in LPF 2 - but I cant' find it (see my initial post about the measurements). Before I now desolder the complete LPF2-path and renew all parts: Any more helpull hints ?
73 Frank
Re: #qmx QMX is up and running - except 30/20 - UPDATE
#qmx
But there is still only very very low output on 30/20. So, for test I changed LPF-assignment for 30/20 to LPF 1 and there at least I could see a much stronger signal on 30 but very low on 20 (ok, the attenuation ist for this bands unsuitable). Therefore, there must be an bug in LPF 2 - but I cant' find it (see my initial post about the measurements). Before I now desolder the complete LPF2-path and renew all parts: Any more helpull hints ?
On Sat, Aug 19, 2023 at 9:16?AM Peter OM4AEI <om4aei@...> wrote:
Hans, i wonder would it be tricky to route the incomming audio through the headphone output for digi mode when in TX? I mean something like a monitor output with volume setting in the digi interface menu. This might be a nice addition to dot, double dot and bar symbols and will nicely confirm what is being sent from fldigi/ft8cn via usb soundcard.
Hans, i wonder would it be tricky to route the incomming audio through the headphone output for digi mode when in TX? I mean something like a monitor output with volume setting in the digi interface menu. This might be a nice addition to dot, double dot and bar symbols and will nicely confirm what is being sent from fldigi/ft8cn via usb soundcard.
I'm unclear what you're asking. I reviewed the previous posts again and I'm still unclear. It appeared to me that you wanted to know if PCB #2 was absent and you were using an external 3.3V source, if that would be OK. But in your latest post you are speaking about?LIN_REG_EN and the onboard 78M33. But "onboard 78M33" is on PCB #2, which you say you want to operate without. So I got really?confused.?
On Sat, Aug 19, 2023 at 1:40?AM Bojan Naglic <bojan.naglic@...> wrote:
OK, thank you for the answer to that. But holding both ADC lines (3V3 and 5V) at 3V3 would mean the LIN_REG_EN signal to go low I assume. So it would switch off the on-board 78M33 and thus prevent the?QMX to operate without the PCB #2 for testing.
All the SMD ceramic capacitors on the board are unimportant non-C0G (means probably X7R). The places where it is important to use NP0/C0G are in the BPR and LPF areas and these capacitors are all through-hole capacitors which are NP0/C0G by Vishay or TDK sourced from Digikey.?
On Sat, Aug 19, 2023 at 3:14?AM Rick NF6G <rdante@...> wrote:
If Hans says X7R dielectric will work fine for C509, I will send you one! Mouser simply does not have 0.1uF C0G 0603 MLCCs. It's the same issue now as when I bought the caps a year and a half ago. It very well might be that C0G is needed elsewhere on the board, but not for C509. Let's see what Hans says, when he wakes up and hopefully sees this.
On Aug 18, 2023, at 19:59, William Wagaman <n3gty@...> wrote:
Hello Bill here N3GTY I assembled a? QDX Version 5. When I power it on it does not initialize. The LED comes on solid. I can enter the Firmware Mode by quickly powering off then back on I installed the latest Firmware ... no change The QDX does show up as a sound device and Serial device. Putty program or any CAT program does not access the QDX
Any ideas as to where to look for the problem would be appreciated
I was asked by Hans to check the voltage on both sides of L16 it measures +5 v to ground on both sides. Leading me to believe that IC10 is defective.?
I put in a help ticket and here is the response I got:
Reply byHans Summers?
Hello Bill
The domain refuses emails from QRP Labs shop. I don't know why.
I can't see anything wrong in your photos that would prevent proper startup. It looks to me that many of the toroid wires don't look well soldered, I wonder if the enamel is properly removed (burnt, sanded, scraped, whatever)? But that would stop you getting power output. Not stop it powering up.
You could also ask on the QRP Labs forum??and there are several people in US, on the forum, who can offer to repair it for you.
73 Hans G0UPL
I did scrape and clean all the?toroid?but as Hans stated in his last message to me find someone here to offer their services to repair it.. I am not asking for that but someone to give me a heads up as to where to look for an issue.? Bye for now de N3GTY
I do have several 100 nf tiny leaded caps I may try while waiting for your gift. Whatever the value of C509 it definitely was 0603 size but on its side. Would still worked except for the solder bridge and probably cold joint. I may have broke it loose during construction but it was definitely gone at first power up.
Thanks for you assistance.? You're right! I hadn't thought about that. It is confusing considering the fact that the C1 is only tuning a tank circuit in the receiver front end.? But I think that's what was happening.? I confused the C1/T1 circuit with the LPF.? ?Let me go back and check again.? Maybe that will provide a clue as to what is going on.? If that doesn't immediately lead me to the problem I'll check all the other things you mentioned too.
Thanks,
Jerry AC5JM??
On Friday, August 18, 2023 at 06:23:26 PM CDT, Ronald Taylor <wa7gil@...> wrote:
Hi Jerry. Yes, this is the group for all things QRPLabs.?
One confusing point in your note ... C1 doesn't have anything to do with output power. It peaks the bandpass filter response, so would normally be peaked with the BPF alignment function (8.7). Sounds like your output power is good. The first thing I always?recommend at this point with a receiver issue is to do the voltage checks on ICs 5-10. With an external DVM, you should read approximately?2.5v on pins 1,2,3,5,6&7 of ICs 5,6,7&8, as well as IC9 pins 5,6&7. You should see about 4.8v on pins 1,2&3 of IC9 and a little less than half the input voltage on pins 1,2,3,5,6&7 of IC10. Please do those measurements and report back your findings.
Also, since this is a Mini, please check the continuity and soldering on the male and female header pins that connect the control board to the main board and also check the connections of the volume?control itself, especially the pin that is grounded. Look for continuity from that pin to the main circuit board ground.
Let us know what you find .. Good luck .. 73 .. Ron
If you have the Tx Attenuator set to zero in fldigi then that is the best you can do as far as audio into the QDX. Of course be sure your system mixer settings are set to 100% for input and output. My linux uses Pulse Audio so Pavucontrol is the name of the mixer. Alt+F2 and type pauvcontrol should bring it up if it's installed. If it's not installed install it "sudo apt-get install pavucontrol" . Some new versions of linux are moving to a different sound system that I know nothing about so can't help with that.
On Aug 18, 2023, at 17:53, Casey Bahr <hansva9@...> wrote:
All measurements of power from a Daiwa meter (lowest range is 15W) via dummy load (very brief tests on antenna almost identical). 20M - 10M power out shows as 2.3-2.5W. I don't, however, think this is a radio problem, but instead I may not be getting enough audio "juice" into it.
I'm on Linux Ubuntu, Fldigi v.****.20 (which has the QDX/QCX hamlib file). The QDX shows up in portaudio devices for the system and in Fldigi. The Fldigi attenuator is at 0.0. The Linux sound devices are the analog QDX ones. The input system volume control acts normally, that is the waterfall brightens or dims moving the slider.
However, there is not slider for the Output setting and fiddling with the overall system volume control has no effect.
So, in short, I think this is a software issue and as I'm not really a Linux whiz, maybe someone else can help me out figuring out if there is a way to boost the output audio, so I can at least see i that's the problem.
73, Casey
Re: Low power on all bands, QDX high bands, assembled at factory
If Hans says X7R dielectric will work fine for C509, I will send you one! Mouser simply does not have 0.1uF C0G 0603 MLCCs. It's the same issue now as when I bought the caps a year and a half ago. It very well might be that C0G is needed elsewhere on the board, but not for C509. Let's see what Hans says, when he wakes up and hopefully sees this.
OK, it CAN be done. First I had the dreaded Q103 short...smoked. Got Q103 and D101 replaced and came alive. Low sensitivity was improved by the #2 mod on the L401 Toroid. (in Han's troubleshooting guide) Then swapped C516 and C525 which were transposed in the assemble manual. Had to use an SMD on C516 and added the 90pf to the other with an SMD in parallel. Really difficult to get those out. Was missing C403 with the kit, but had a 22pf disk in stock. ? Been A/B'ing it with the QCX mini (different RX I know). Putty'ed in and upped the audio gain on 20 meters to 80 and other bands to 65. Now it's within maybe 5 dB of the QCX and 7dB of my IC-7610. I call that totally usable. I'm going to stop working on it for a while and just make some QSO's. Got a 599 out of Ontario as #1 on 20 CW . Yea. Thank you Amazing Hans!
Re: Low power on all bands, QDX high bands, assembled at factory
Study the manual on how the QDX works, and you will find that the audio level of the input has no effect on the power output. There is either enough audio to turn the transmitter on at full power, or there is not. ?While it is marginally better for frequency stability to turn the output all the way up (and drive a digital square wave into the radio), there is no output power control. Is it possible that the radio was built for 12 V and you are running it on 9 V?
On Aug 18, 2023, at 6:53 PM, Casey Bahr <hansva9@...> wrote:
?
All measurements of power from a Daiwa meter (lowest range is 15W) via dummy load (very brief tests on antenna almost identical). 20M - 10M power out shows as 2.3-2.5W. I don't, however, think this is a radio problem, but instead I may not be getting enough audio "juice" into it.
I'm on Linux Ubuntu, Fldigi v.****.20 (which has the QDX/QCX hamlib file). The QDX shows up in portaudio devices for the system and in Fldigi. The Fldigi attenuator is at 0.0. The Linux sound devices are the analog QDX ones. The input system volume control acts normally, that is the waterfall brightens or dims moving the slider.
However, there is not slider for the Output setting and fiddling with the overall system volume control has no effect.
So, in short, I think this is a software issue and as I'm not really a Linux whiz, maybe someone else can help me out figuring out if there is a way to boost the output audio, so I can at least see i that's the problem.
No matter. I really appreciate your effort! That is so inadequate for thanks but I am extremely greatful! I may have a couple of ceramics that may be small enough....with the apparent confusion about how big goes where maybe there is huge latitude!
I still have to see if VFO A or B is what has been selected. And thanks to the rest of you guys supplying suggestions! I ran out of altitude, airspeed and ideas about three pages ago and you all have spurred me on! HHO-rah!
Karl
Bob Nagy AB5N