|
Hi, ubitx-ers!? I've assembled my ubitx, but have no audio out of speaker jack.? I've double-checked the brown & black wire connections all the way from the exposed debug speaker I built to the connector on ubitx board via my 3.5 mm connector and jack.? The debug speaker works with my cell phone audio so I know the external plug, wiring, and speaker are ok.? The audio 10k pot is correct with orange and yellow corrections from forum and pot checks ok with oh meter.? The display comes on 40 meters with no tx.? The idle current draw RX into a dummy load? is about 160 ma at the DC input.? I plan to continue debug, but have a basic question: shouldn't I hear some sort of audio static even while connected to a dummy load???
Thanks!
Tom
AB7WT
|
Tom - Yes, you should hear something. ?The idle current seems a bit high to me but the meter on the supply I'm using right now isn't accurate enough at low current to be much help. ?
Howard K4LXY
|
Thank you, Howard!? Good to know for sure. Based on that, I'll take the next debug steps.
Tom
AB7WT
|
BTW: side note regarding the idle current, during the early DC connector wiring check, it was 78 ma (the instructions said it should be 90 to 110 and I figured 78 was close enough).? The 160 ma idle current was after all the other wiring was done and the Arduino and display was added.
Tom
AB7WT
|
Very Interested in this as I have exactly the same issue.
|
Tom,
First check your audio amp. Keep the volume midway and If you touch the volume control leads you should hear a hum in the speaker.
A picture of your U1 TDA2822 will help.
You should hear a hiss even with a dummy load. A few feet of wire for an antenna should bring in some signals.
Raj
toggle quoted message
Show quoted text
At 3/5/2018, you wrote: Hi, ubitx-ers! I've assembled my ubitx, but have no audio out of speaker jack. I've double-checked the brown & black wire connections all the way from the exposed debug speaker I built to the connector on ubitx board via my 3.5 mm connector and jack. The debug speaker works with my cell phone audio so I know the external plug, wiring, and speaker are ok. The audio 10k pot is correct with orange and yellow corrections from forum and pot checks ok with oh meter. The display comes on 40 meters with no tx. The idle current draw RX into a dummy load is about 160 ma at the DC input. I plan to continue debug, but have a basic question: shouldn't I hear some sort of audio static even while connected to a dummy load?
Thanks!
Tom
AB7WT
|
Thank you, Raj!
I'm wondering if U1 TDA2822 might be bad.? Visually it looks OK and it doesn't smell burnt, but I have no static or hiss in the speaker by touching potentiometer leads, etc.? I ohm'd out connections from the TDA2822 pin 1 to the pot and the speaker via C77 and they look good.? I confirmed that pin 7 goes to VOL-M via the orange wire.? On item that confuses me a little is the wiring instructions show a 100K pot with no on-off switch connections, while my pot is 10k with on-off.? Also the instructions say to attach the green wire to the pot ground lug but my 10k pot does not connect any of the 3 lugs to ground (instead, the green wire gets ground via the ubitx board connector).?
Unfortunately, I no longer have an oscope, so I'm limited to how much I can check on U1.? It does show good 12v to pin 2.? I'm thinking I may need to order another TDA2822 and replace it (if I don't get a scope soon enough to do more checking).? If I do replace it, I wonder if it would cause any issues if I put in an IC socket for mounting?
I'm open to anything obvious anyone might see that I'm missing.? Enclosed are pictures of my pot wiring and U1.
Thanks!
Tom
AB7WT
|
|
|
Tom, Got it!
Your speaker connection on the socket is wrong. You have connected the wire to the middle sleeve of
a stereo plug.
As your photo shows, please connect to the RIGHT side pin closest to the front panel or black wire.
Raj
toggle quoted message
Show quoted text
At 06-03-18, you wrote: Here's the pictures.
Tom
|
With pot at mid range, a finger on the middle pot wire that feeds the TDA2822 should definitely make some noise. Yes, the pot in the photograph in the wire-up instructions shows a pot without a power switch, different than the one that comes with the kit.? The one in the kit is 10k, though that is not critical. The pot ground lug is whatever lug gets the green wire, you could wire it to the lug on the opposite side from what is shown in the picture but then fully clockwise would be minimum volume. As stated before but worth repeating, the picture is correct with wires in green-orange-yellow order, the diagram at the top of the page incorrectly shows orange and yellow swapped. What TDA2822 do you have on the board?? Does it have a WX or FCI brand marking? The WX parts have been rather unreliable, the FCI seems to work, I believe all boards from hfsignals thus far have been using one or the other. May be other clone manufacturers besides WX that give trouble, I wouldn't buy anything for which you can't obtain a datasheet.?? If you happen to have an LM386 on hand, check this post and the thread around it: ? ?? /g/BITX20/message/43156You may want a 1uF cap between pins 1 and 8 of the LM386, this post incorrectly suggests 0.1uF: ? ?? /g/BITX20/message/43189Alternately, could take that wire from the center lug of the volume pot and run it into a known good LM386 amp in some other gear instead of into the uBitx's TDA2822. You will also need a ground wire over to that other gear. Jerry, KE7ER
On Mon, Mar 5, 2018 at 11:58 pm, Tom Christian wrote:
I'm wondering if U1 TDA2822 might be bad.? Visually it looks OK and it doesn't smell burnt, but I have no static or hiss in the speaker by touching potentiometer leads, etc.? I ohm'd out connections from the TDA2822 pin 1 to the pot and the speaker via C77 and they look good.? I confirmed that pin 7 goes to VOL-M via the orange wire.? On item that confuses me a little is the wiring instructions show a 100K pot with no on-off switch connections, while my pot is 10k with on-off.? Also the instructions say to attach the green wire to the pot ground lug but my 10k pot does not connect any of the 3 lugs to ground (instead, the green wire gets ground via the ubitx board connector).?
Unfortunately, I no longer have an oscope, so I'm limited to how much I can check on U1.? It does show good 12v to pin 2.? I'm thinking I may need to order another TDA2822 and replace it (if I don't get a scope soon enough to do more checking).? If I do replace it, I wonder if it would cause any issues if I put in an IC socket for mounting?
I'm open to anything obvious anyone might see that I'm missing.? Enclosed are pictures of my pot wiring and U1.
|
On Tue, Mar 6, 2018 at 12:47 am, Raj vu2zap wrote:
Your speaker connection on the socket is wrong. You have connected the wire to the middle sleeve of
a stereo plug.
Thank you, Raj.? For debug, I wired the socket to the middle sleeve of the plug so it would match my cell phone.? Then to eliminate the plug being miswired, I ran jumpers directory from the brown wire to by debug speaker plus and black to speaker minus.? This should have eliminated the connector I'm thinking. Tom
|
Thanks for the good input, Jerry!?
I don't have a spare LM386 or a spare rig right now (I'm rebuilding a new ham station from scratch after loaning out my other HF gear to a newer ham).?
I'm thinking that U1 is probably bad.? It's a WX type.? So, I ordered some TDA2822 replacements and sockets which should be here next week (ordered extras for spares).? Hopefully, that will do the trick.? Will post back the results.
Tom
AB7WT
|
I replaced U1 and it fixed the problem.?
The part I received today was a batch of ST Microelectronics TDA2822M chips from Juried Engineering on Amazon .
Thanks for all the help!
Tom
AB7WT
|
I was very cautious and finally got the uBITX?wiring correct after looking at all the posts.? It was receiving great until I unplugged my headphones and
plugged in a speaker.? I fried U1!? My speaker plug was not stereo it was mono plug!? So that's why U1 audio amp fried.? So I just ordered 2 TDA2822M's
from Amazon.com.? I am unable to use the uBITX until I replace U1.
I am very upset about this audio circuit design!? This circuit seems to be the Achilles heal of this radio, including a?very loud popping between?receive/
transmit.? I would?like to use a speaker in the future.? I will?be sure to be very careful of the wiring of any?speaker.? I hope to have my first contact soon!
A very unhappy
Rod, WA9GQT
|
What was the logo on the fried U1? Does it? say "WX TDA2822"? Does it say "FCI TDA2822"? This is important. I suspect that a good TDA2822 will not fry with a short unless you have the volume turned way way up. And that you have the WX clone. But I could be wrong. Here's the latest news regarding the bad chips: ? ?? /g/BITX20/message/44394? ?? You can probably find an LM386 locally or in some older project that can be hacked in there temporarily till you get a new TDA2822 in from Mouser or Tayda or similar. Choosing a $109 all HF band SSB transceiver means you get to deal with this sort of thing. Jerry
On Wed, Mar 14, 2018 at 10:31 am, <WA9GQT@...> wrote:
I was very cautious and finally got the uBITX?wiring correct after looking at all the posts.? It was receiving great until I unplugged my headphones and
plugged in a speaker.? I fried U1!? My speaker plug was not stereo it was mono plug!? So that's why U1 audio amp fried.? So I just ordered 2 TDA2822M's
from Amazon.com.? I am unable to use the uBITX until I replace U1.
I am very upset about this audio circuit design!? This circuit seems to be the Achilles heal of this radio, including a?very loud popping between?receive/
transmit.? I would?like to use a speaker in the future.? I will?be sure to be very careful of the wiring of any?speaker.? I hope to have my first contact soon!
A very unhappy
Rod, WA9GQT
|
Thanks Jerry,
It was a WX TDA2822. ?I found that?Gateway Electronics here in St. Louis has the TDA2822M chips in stock. I put 3 chips on hold
and was able to cancel my Amazon.com order in time. Hopefully that will give me a better chance of getting a good IC.
73, Rod
|
I'm curious what maker's mark you find on those new chips from Gateway,
and how well they work for you.
Seems to be a half dozen different flavors out there.
Some of the clones are kind of sour, as you have noticed.
toggle quoted message
Show quoted text
On Wed, Mar 14, 2018 at 11:52 am, <WA9GQT@...> wrote:
Thanks Jerry,
It was a WX TDA2822. ?I found that?Gateway Electronics here in St. Louis has the TDA2822M chips in stock. I put 3 chips on hold
and was able to cancel my Amazon.com order in time. Hopefully that will give me a better chance of getting a good IC.
|
Rod, Do your headphones have a stereo/mono switch? If so just unwire the speaker lead going to the ring contact on the audio jack and set your headphones to mono. That's what I am doing (actually I used a mono jack instead of a stereo jack). Then if I plug in a speaker using a mono plug everything will be copacetic. tim ab0wr On Wed, 14 Mar 2018 10:31:10 -0700 "WA9GQT via Groups.Io" <WA9GQT@...> wrote: I was very cautious and finally got the uBITX?wiring correct after
looking at all the posts.? It was receiving great until I unplugged
my headphones and plugged in a speaker.? I fried U1!? My speaker plug
was not stereo it was mono plug!? So that's why U1 audio amp fried.
So I just ordered 2 TDA2822M's from Amazon.com.? I am unable to use
the uBITX until I replace U1. I am very upset about this audio
circuit design!? This circuit seems to be the Achilles heal of this
radio, including a?very loud popping between?receive/ transmit.? I
would?like to use a speaker in the future.? I will?be sure to be very
careful of the wiring of any?speaker.? I hope to have my first
contact soon!
A very unhappy
Rod, WA9GQT
|
Thanks Tim, My headphones are stereo without a switch. Sounds like using a mono jack and mono plug for the headphones may be the best?thing to do.
Then?using mono plugs on speakers?will work OK.? I am also going to install an?IC socket for U1. Seems that is a good idea for these audio amp chips.
I am off to Gateway Electronics today.? Guess I will see if they have TDA2822M type FCI or WX. ?I will get the FCI type if possible.
Thanks again,
73, Rod
|
Hi Tim,
The TDA2822M's I got from Gateway Electronics had SSS 88737 no FCI or WX.? The sales person said this was a manufacture date code?of 1988.
He stated that these IC's must be better than the newer?FCI or WX types. ?I removed the bad TDA2822M and installed an IC socket in U1 on the board.
I installed?one of these new IC's ?and the?Ubitx is?working great again.? I tried transmitting and only have 2 watts out on 30 meters. I may need to peak
the output power.
73, Rod
|
Andy Robins
Raj vu2zap
