Don't know when I get to it.. but I will follow your lead.
I already ordered some germanium diodes to build a RF probe.

To be continued..

John

Yes, if you can transmit CW then it has to be somewhere between Q6 and Q22,
since CW is transmittted by unbalancing the modulator immediately following Q22.
If the receiver works, then the three mixers and local oscillator are ok.
So if you still have trouble transmitting SSB, then it's Q6 or one of the bidi amps on the TX side,
and the bidi amps seldom give us trouble.

You could try unbalancing the modulator by injecting 5vdc through a series 4.7k resistor
at T7 pin 3 (and pin 5).? This is how we generated CW on the Bitx40:??
? ??
If that does transmit CW, then it has to be around Q6.

Your 10mhz scope may just barely see something in the 12mhz IF section through Q42,?
and probably nothing at all in the 45mhz IF section at Q20,21,22.
If you wind up debugging those sections, you may need to build a diode RF probe or something similar.

Jerry

I ordered them from China, but on eBay I found an US seller with the TDA2822L. Specs seemed to be similar.

Maybe I was to slow plugging the headset I.

John

Let me second Neil's evaluation of Carl’s cases. They are excellent and he is a great ham to deal with. 73 Mike KF6KXG

I did have power on CW, at least the first day before so smoked U1 with a stereo Sony noise canceling headset.
I didn't have my straight key yet bit i just shorted a cord that i had plugged in the key jack.

Had some trouble getting the scope to sync but the signal on the collector of Q6 was much stronger than the Mic input.

Scope has 10MHz bandwidth so it should work on the lower bands.

Most likely the TDA will arrive saturday than i can start from scratch again.
Will measure the voltages as you mentioned. But as CW seemed to work the first day I thought I had to look somewhere in the modulating circuitry. Have the schematics printed but in my professional career I worked more with higher voltages.
Am not afraid to try but just need some guidance as I am fairly new to radio electronics.

John

So where did you get your spare TDA2822M's?

The TDA2822M is $7 for two on ebay, quite expensive for what it is.
Mainline distributors like Mouser and Digikey say it's discontinued.
ST no longer makes it, sources may be drying up.

My uBitx has a part on it marked "TDA2822M" but no ST logo, not sure who makes it.

Banggood has this amp, photos show it to be stuffed with a UTC2822H clone, but I'm having no luck finding a source for that chip either.
??

Someday we might need to find a replacement.
Maybe a little PC board with 8 header pins.
Stuff it with a bunch of mmbt3904's if nothing else.

Curious that the stereo headset fried the TDA2822M.
Perhaps it presented too low an impedance when first plugged in for some reason??

Not at all clear from the datasheet that the TDA2822M will survive a 4 ohm speaker
when powered from a 12v+ supply.

Jerry, KE7ER

I fried mine when I plugged in a stereo sony noise canceling headset.
So it does not only happen with mono plugs.

Hopefully the spare TDAs with sockets will arrive soon so Incan start troubleshooting my no power problem.
To be on the safe side and avoid another wait I also ordered some IRFs ;)


John

On Wed, Feb 28, 2018 at 01:38 pm, Jerry Gaffke wrote:

ACE Hardware store has an amazing
collection of nuts and bolts and spacers, nylon and brass and steel, imperial and metric.
Including some nice generic knobs for electronics.?

I was just there last Saturday to get some M3 screws.? I didn't even think to look for knobs!? I'll pay more attention next time, and maybe have some coffee before I go.

For those in the US, bereft of a 3D printer, our local ACE Hardware store has an amazing
collection of nuts and bolts and spacers, nylon and brass and steel, imperial and metric.
Including some nice generic knobs for electronics.? ?

Nylon spacers are easily cut to size with an Xacto knife.

Jerry, KE7ER

开云体育

Here is my BitX..

3D printed spacers, Knobs, and Bezel.? It is like cheating to make exactly the spacer you need!? Since they are ABS, I can heat a 4-40 bolt on the stove and TAP them with treads too.?? The LCD Backlight has a bump at one end,? so to get the LCD parallel you need an inside spacer about 1/8".

Mike, WA6ISP

?

From: [email protected] [mailto:[email protected]] On Behalf Of Michael Hagen
Sent: Wednesday, February 28, 2018 11:18 AM
To: [email protected]
Subject: Re: [BITX20] ubitx standoffs #parts

?

They are metric 3 mm.? So you have to use 3mm bolts those for the supplied spacers.

Most places have plastic spacers too.? Get 4-40 size ones.? Un-threaded 0.096" or 0.1" and you can use #4 sheet metal screws or self thread 4-40 screws.? Check Mouser.? Or mail order surplus, like All Electronics.

Buy long ones and cut them off to the length you need.?? The ACE and other local hardware stores have brass and Al. tubing for model making.

K&M Metals or some name like that.? Al. , Brass, or Copper is easier to work with than steel.

You could cut up spacer from them too.? Could even go to putting nuts at the other end?

Our local ACE has a whole section of hardware, including Metric.

?

73's Mike WA6ISP

?

?

On 2/28/2018 8:20 AM, R S via Groups.Io wrote:

This Group is mighty nice.? I have enjoyed it tremendously for a while now and have learned from others here.? I have a question now.? I have installed my xbitx in an old junked Repeater Case, no testing yet, but I would like to have better choices with the standoffs for the board and display.? The display is a little too far in for my total liking.? Maybe you can see with pics.? Not finished yet.? What are the threads per inch (maybe 4-40) and so on?? I ordered some from Mouser but were surely not what I wanted and expected.? Any help is surely and greatly appreciated.

Ron
KJ4FFG

-- 

Mike Hagen, WA6ISP

10917 Bryant Street

Yucaipa, Ca. 92399

(909) 918-0058

PayPal ID? "MotDog@..."

Mike@...

-- 
Mike Hagen, WA6ISP
10917 Bryant Street
Yucaipa, Ca. 92399
(909) 918-0058
PayPal ID  "MotDog@..."
Mike@...

EVENT CATEGORY
01 Mar 18 5:40 AM - Customs status updated - MELBOURNE,AUSTRALIA

Further Details -?Shipment has been given a release by Customs.
Next Steps -?Unless there is an adhoc exam or a stop by another regulatory authority the shipment will proceed to delivery

?

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Should we add Carl's case to the ubitx.net enclosures section.

I purchased one of these, by the way, and the quality is excellent!!

--Neil, W2NDG

I'm glad that works for you.
But when concocting a recommended solution across thousands of rigs,
we'd best somehow make the rig survive an audio short to ground.? ?
Or this forum will getting traffic about fried TDA2822M's for years to come.

Re-read this post:??/g/BITX20/message/42723

Adding a series 8 ohm 1/2 watt resistor between the uBitx board and your phone jack should?
safely prevent any damage, though it will reduce the maximum available audio.

Could be that 4 ohms is sufficient.
?
Jerry

Mike, I left out the statement:? very clean lines and sweet looking in and out.? Good work.

Ron ? KJ4FFG

So what is the universal fix?? if a mono jack is plugged into a stereo jack on another electronic device it does not destroy the audio output of those devices.

How do they prevent damage on many other devices with stereo jacks?

--
73, W9KJO
Walter