I guess I'm old school. ?Or one reluctant to complain.

If it's cheap and WORKS, DON'T 'FIX'IT! ? Period.

If it's expensive and has problems, RETURN it. Period.

If you like to modify it, have at it, AND DON'T COMPLAIN!?

If you get a violation notice, get a new radio, don't complain.

I'm happily using one and just tinkering with another just to refresh my memory from long ago when I was an 'expert' according to some.

Grateful to Farhan for this innovative toy radio (that is as sensitive as my Icom 7300) and that I could afford TWO of them.
?
Note on the 15v mod. I've ordered a mean well supply adjustable from 13.8 to 15 for under $20. Stay tuned for a report.

There's an awful lot of gain between Q90 and the IRF510's.
If that trace between the relays for rx is not grounded during transmit, it will carry enough RF energy
to create a really impressive oscillator.
Unfortunately, it won't necessarily be at the operating frequency.

Jerry, KE7ER

开云体育

I will do this the next time I can get to our latest an greatest R&S FSWP in my QRL

Henning Weddig

DK5LV

In transmit, the trace between K3 pin 14 and K1 pin 12 is disconnected from the antenna at K3 and connected to ground at K1.? What is the designer's intention for doing that?? Wouldn't disconnecting the trace from the antenna be enough?

David,? the web page has a wiki...

Maybe the mods could harvest info and post there or borrow from mike at ubitx.net.

Allison

I am looking for a ready built SI5351 board, with isolating transformers.

If you haven't installed a cap on the output of the DSP audio filter I suggest doing so. Without it I had a lot of strange things going on with my audio as I believe that there is DC voltage present on the output that was messing with the audio amp.

Michael VE3WMB

Sarma

Thank you for the great suggestion. This design is not from me. It is the work of?Kees K5BCQ. I agree...... a very nice job and I look forward to testing it.

Warren - WA8TOD

Hi Darren, VE3XLT
Can you please make this correction to? CEC 1.097 Nextion screen for my basic 3.5" (tft) display?

TA2FU Alper?

On key down it should well over 2A.

Still working on this. Speaker and audio out jack are wired correctly. So's the pot. It's supposed to be 10K right?

I have both a paddle and straight key jack wired up according to
https://ubitx.net/wiring-up-a-paddle-and-straight-key/

The overall box draws about 500ma upon power up (with loud buzz from the speaker). That seems a bit high. There's nothing going out the antenna jack. What's the nominal value?

When I depress a straight key (plugged in to the key jack, so bringing the KEYER line straight to ground) the buzzing either stops or pulsates, like the internal keyer is doing its thing. Current consumption goes over 1A and I am seeing power going out the antenna. So that's good, I guess. I measure 5 volts on the KEYER line when nothing's pressed, so the 4.7k pull-up is working.

Could it be RF getting loose and feeding into the audio front end?

My LCD appears blank on the top line, and a series of fully-filled-in rectangles on the bottom line, no matter how I twiddle the trimmer on the back of the Raduino. Is that indicative of some wider problem?

Thanks for your troubleshooting brainstorming thoughts. :)

73,
MIcah AJ6BD

开云体育

On Wed, Aug 22, 2018 at 09:16 PM, ajparent1/KB1GMX wrote:

K1 talks to K3 for Rf path.

The 12VDC side of K1 is successfully telling K3 what to do.? If K3 is not listening and is stuck in receive, then the transmit RF from the PA will dead end in K3 and the PA transistors will get hot.? They are not getting hot, so I don't think K3 is sticky.

Apologies if I did not make it clear that the 12VDC control signals from K1 all appear to be working correctly on TX and RX.

David,

You must have missed the last three months.... and a pair of very long threads!? ;)

To clean that up yes, band pass filters are the option or some very fancy combination of
high pass and low pass which results in the same pass band as a band pass.

Generally the in band spurs happen to be extremely weak and as such not a worry
other than being annoying on receive.

Allison

K1 talks to K3 for Rf path.? Look at the schematic.

Allison

It's funny, I have been working on getting my Laserbeam set up. Yesterday I wired it up pretty much the same (minus the extra components as they were not mentioned in the set up for the LB) But I have a DPDT for the power, and switching it into the circuit, and a SPST switch for the 1-4dB gain. The only difference was that he put it before the pot, not after like I had done. So... Today I put it before the pot. It's still not right though. When I switch it into the circuit it's like the audio gets sucked out of the thing. My LED indication is all wrong too. I have also noticed that since I put it in, I have a birdy farm. I am going to have to rethink how I have it, and where I have it. I have my uBitx in an extruded aluminum case, so I might raise the board up a couple levels and get the Laserbeam right next to the volume knob so there's very little wire between the ins and outs. Right now there's too much wire. But I also need to sort out why it's not working.?

When it's switched in, it's like the audio is no longer being amplified. If I switch in the +4 gain, It's just minimal audio. I have the LEDs set up on an RGB led, red being peak, Blue being Band width, and green being center freq.?

Good Evening, All.

My K1 relay was getting intermittently sticky on TX, so I decided to replace it.? I used an AXICOM with the same pinouts as the stock Hongfa.? I'm not very good at desoldering and tore up some of the pads on the board. A little finagling and everything on the DC side of the relay seems to be working. The connections labeled TX on the schematic are getting 12V, and the connections labeled RX are getting 12V when they're supposed to and 0V when they're not supposed to.

Oh dran!

Any idea where the sparks came from?
Any obvious scorch marks?

Sounds like you bumped L8.
Look at the schematic, L8 feeds 12v from PA-PWR into the left side IRF510.
I have no idea what "bumped" means, but if you shorted the wire that L8 is wound with to ground somehow,
that will burn out the trace between L8 and PA-PWR.
It's possible you burnt the coil, does the wire look discolored?
Just holding the red voltmeter probe against L8 while the black probe is on ground would not do this,
because very little current would flow through the voltmeter..

With the power supply disconnected entirely, short the PA-PWR wire to ground
then short each IRF510 tab to ground.? This is to make sure any caps are discharged.
Then set the DVM to the lowest ohms scale and measure ohms from PA-PWR?
to each IRF510 tab in turn.? Both tabs should be close to zero ohms to PA-PWR.
If one reads a lot more than zero ohms then either the coil (L8 or L9) or the traces
got burned.

A scorched trace could be easily repaired by soldering down a piece of wire.
I doubt you blew the IRF510's or any other semiconductors.

The gates should not be zero volts when you are transmitting, should be about 4 volts.
ff they were zero volts when transmitting, then that was your original problem
Otherwise the rig was working.


Might be a good idea to lug it off to a local ham club,
explain your adventure to some of the others attending
see if somebody there is curious enough about the uBitx?
to look it over with you and show you the ropes.

Jerry