Re: I need a V3 or V4 uBitx board.
Thanks for all the great replies, I'm really embarrassed to admit I did this. Jerry, you are right about what caused this. It didn't work at all when I tried it the first time, after looking at everything I thought I had the wire going to C50 on the click board on the wrong pad, so I swapped them, (big mistake), now at least I had bad receive, then I pushed the PTT, that's when the magic smoke got let out. I checked the raduino outputs with my frequency counter and the outputs were all what they should be for the frequency I was on. C50 and C63 are replaced with new caps and are fine. I will check the other things you mentioned as well. Thanks for the offers to buy my board, but that doesn't really help me with my problem. I will try to repair before I think about selling it. Thanks again for all your help. I will post on this thread and let you all know how things turn out. Picture of top side of PCB below. Joel N6ALT 
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I repeated the test using my highly accurate Harbor Freight meter.? ;-)
Not the needle on my old linear power supply.
My figures now agree with Don's measurements to within a couple ma.
?
Voltage should not affect the current draw by much at all.
Should be the same current with 8v as it is at 15v into the Raduino, within a couple ma.
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On Sat, Jun 23, 2018 at 11:09 am, Don, ND6T wrote:
OK, I just did the same test. Brand new, just out of the box, 12.5 volt source. I get 61.5 milliamps. De-power. Unplug the display. I get 40.8 milliamps when repowered. -Don
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Re: I need a V3 or V4 uBitx board.
Joel,
Since it did not go poof until you activated the PTT, then it might have been an incomplete cut of the TX trace. With both TX and RX voltages active then both sets of IF amps will be active (truly bidirectional) and will likely form a full-on oscillation! Check Q12, Q21, Q32, and Q40 as a start. Like Mike says, look for discoloration. Sniff the areas. -Don
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On Sat, Jun 23, 2018 at 11:09 am, Don, ND6T wrote:
OK, I just did the same test. Brand new, just out of the box, 12.5 volt source. I get 61.5 milliamps. De-power. Unplug the display. I get 40.8 milliamps when repowered. -Don
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Re: I need a V3 or V4 uBitx board.
Joel, The first thing I would do is find the trace you burnt on the schematic. Then I would look at the steps that you took to install the mod and see if/how they are related.
Let us know what you find.?
Mike M.? Ku4qo?
On Sat, Jun 23, 2018, 1:55 PM Joel Caulkins < caulktel@...> wrote: I debated on whether I would admit to being this stupid to the group, but while fitting the click fix board to my perfectly working uBitx all mounted in a custom enclosure, I vaporized a trace on the bottom of my board. Obviously I did something wrong, although I don't know what. I reversed the mods to the PCB and replaced the vaporized trace with a piece of wire and fired it up. I have no RX or TX however the Raduino is working and outputting the correct clock signals on the three pins. It does switch to TX when pressing the PTT, and believe it or not, the whole audio section seems to work fine. I can touch parts in the audio section and hear a loud 60 cycle hum out of the speaker. I can hear a slight hiss in the speaker that does not change when removing the antenna. So this brings me to the part where I ask if it would be worth trying to trouble shoot this board, (any idea where to start?) or just replace it. Does anybody have just a Ubitx PCB they would sell me (cheap) as my raduino works fine. This radio worked good, I should have left it alone:-( Picture of burnt trace below.
Joel
N6ALT
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Re: I need a V3 or V4 uBitx board.
No worries, Joel! Although I am sorry that it happened. The trace appears at first glance to be the TX trace. If it were cut in the wrong place and jumpered to the +12 volt bus then you were probably transmitting. Look at the PA finals. Best to check resistances in several places in the TX areas. No, it can be repaired. Just a bit of an adventure.
I advocate using a current limited supply to avoid that. I dial the maximum current down to just over what I would expect to be normal before applying power. In this case a 0.2 amp current fold-back would be appropriate. By observing the voltage with your finger on the switch you can usually avoid most unpleasantries. Drop me a line on my regular email if you want. 73,
Don
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Re: I need a V3 or V4 uBitx board.
Easy enough to foul up like that, I've done worse.
More than once.
Well worth an hour or two of trying to chase this down.
I'd expect it to be repairable.
The trace you burned is the TX +12v rail.
My best guess is it somehow got wired up to ground during your mods.
Look hard for other burn spots where the TX rail might have been damaged.
And look hard at wherever it had been shorted, may be some damage there too.
Verify that your RX rail is 12v during receive and TX is 12v during transmit.
Sounds like that is probably the case.
Exactly what list of mods were you trying to follow?
Exactly what was the mis-wire?
Where do you hear 60hz hum when probing around the audio during RX?
Do you get noise when touching T7 pins 3 and 5?
Did you restore C50 and C63?
Perhaps C63 got cracked when working with it, perhaps receive audio is?
not making it through C63.? Perhaps try replacing C63 with some other cap of 0.1 to 1 uF.
Maybe the traces got ripped up a bit around C63 when it was removed?
You can continue? touching stuff back through the receiver all the way to the antenna,
should hear increasing noise as you continue further back.?
Just touch it with 3 feet or so of wire connected to nothing, that's enough of an antenna
to pick up household QRM and inject it into the circuitry.
The further back you go, the more amplification it gets before arriving at your speaker.
When you get to a spot where touching stuff no longer makes an audible difference,
you have gone past the fault in the receiver.
If there's loss of noise at or immediately beyond a mixer (other side of the filter that's in front of the mixer)
then check the si5351 clock going into the mixer.? You can check the si5351 clocks by monitoring them in some
other shortwave receiver.? ?With stock firmware, Clk0 is around 11.9965 mhz, Clk1 is at 32.995mhz (LSB) or 56.995 (USB),
and Clk2 is at the 44.995mhz+OperatingFreq.? So if you are tuned to 7mhz, then clk2 should be within a few khz of 44.995+7=51.995mhz
Jerry, KE7ER
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On Sat, Jun 23, 2018 at 10:55 am, Joel Caulkins wrote:
I debated on whether I would admit to being this stupid to the group, but while fitting the click fix board to my perfectly working uBitx all mounted in a custom enclosure, I vaporized a trace on the bottom of my board. Obviously I did something wrong, although I don't know what. I reversed the mods to the PCB and replaced the vaporized trace with a piece of wire and fired it up. I have no RX or TX however the Raduino is working and outputting the correct clock signals on the three pins. It does switch to TX when pressing the PTT, and believe it or not, the whole audio section seems to work fine. I can touch parts in the audio section and hear a loud 60 cycle hum out of the speaker. I can hear a slight hiss in the speaker that does not change when removing the antenna. So this brings me to the part where I ask if it would be worth trying to trouble shoot this board, (any idea where to start?) or just replace it. Does anybody have just a Ubitx PCB they would sell me (cheap) as my raduino works fine. This radio worked good, I should have left it alone:-( Picture of burnt trace below.
Joel
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Re: I need a V3 or V4 uBitx board.
If you decide not to fix it I will buy it from you.
73 Dick
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Sent from for Windows 10
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I debated on whether I would admit to being this stupid to the group, but while fitting the click fix board to my perfectly working uBitx all mounted in a custom enclosure, I vaporized a trace on the bottom of my board. Obviously I did something wrong,
although I don't know what. I reversed the mods to the PCB and replaced the vaporized trace with a piece of wire and fired it up. I have no RX or TX however the Raduino is working and outputting the correct clock signals on the three pins. It does switch to
TX when pressing the PTT, and believe it or not, the whole audio section seems to work fine. I can touch parts in the audio section and hear a loud 60 cycle hum out of the speaker. I can hear a slight hiss in the speaker that does not change when removing
the antenna. So this brings me to the part where I ask if it would be worth trying to trouble shoot this board, (any idea where to start?) or just replace it. Does anybody have just a Ubitx PCB they would sell me (cheap) as my raduino works fine. This radio
worked good, I should have left it alone:-( Picture of burnt trace below.
Joel
N6ALT
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Re: I need a V3 or V4 uBitx board.
I forgot to mention that the board smoked when I pushed the PTT, it was working sort of until I did that.
Joel
N6ALT
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Remi,
OK, I just did the same test. Brand new, just out of the box, 12.5 volt source. I get 61.5 milliamps. De-power. Unplug the display. I get 40.8 milliamps when repowered. -Don
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Unplug the display.
Then how much does the main Raduino board draw?
I measured mine (crudely though, at the bottom end of my power supply's ammeter) at 60ma.
Verify that the voltage out of the LM7805 is 5 volts.
Is something other than the LM7805 also getting hot?
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On Sat, Jun 23, 2018 at 09:48 am, f1mqj wrote:
My raduino alone (now, it was more yesterday) consume 230mA on a 12V battery
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I need a V3 or V4 uBitx board.
I debated on whether I would admit to being this stupid to the group, but while fitting the click fix board to my perfectly working uBitx all mounted in a custom enclosure, I vaporized a trace on the bottom of my board. Obviously I did something wrong, although I don't know what. I reversed the mods to the PCB and replaced the vaporized trace with a piece of wire and fired it up. I have no RX or TX however the Raduino is working and outputting the correct clock signals on the three pins. It does switch to TX when pressing the PTT, and believe it or not, the whole audio section seems to work fine. I can touch parts in the audio section and hear a loud 60 cycle hum out of the speaker. I can hear a slight hiss in the speaker that does not change when removing the antenna. So this brings me to the part where I ask if it would be worth trying to trouble shoot this board, (any idea where to start?) or just replace it. Does anybody have just a Ubitx PCB they would sell me (cheap) as my raduino works fine. This radio worked good, I should have left it alone:-( Picture of burnt trace below. Joel N6ALT 
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tnx don, larry, jerry My raduino alone (now, it was more yesterday) consume 230mA on a 12V battery 
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If I just power up my raduino it draws about 100ma.
nothing else connected, the display works, backlight is on.
Without the display, more like 60ma.? Most of that is probably backlight.
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Re: Understanding Spurious Emissions
Will I have been thinking along the same path and right now it is in the noodling/research stage. I need to get spice on my computer to do some modeling.?
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On Jun 22, 2018, at 21:46, William Kimber < zl1tao@...> wrote:
On 21Mhz rather than a band pass/high/low filter what about 23mhz
trap(s) also called notch filter. Even high Q should be wide
enough to cover whole 23.8 to 23.55Mhz.?? Similar for? 24Mhz??
needs to cover 20.17 to 20.01Mhz
Cheers,
Will
ZL1TAO
On 23/06/18 13:33, Jerry Gaffke via
Groups.Io wrote:
Table two of the
filter reference shows that the 21 mhz bandpass filter?
has 15db of attenuation at 28mhz, that's 7mhz away.
We need something like 20 dB of attenuation at 2mhz away.
As Allison says, that's a tough nut to crack.
And I have my doubts about the filter I pointed to.
Jerry
On Fri, Jun 22, 2018 at 04:31 pm, Gordon Gibby wrote:
Forgot to put the link.
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Re: Blown (socketed) TDA2822?
Some of the clones are going for the lowest possible price, and fab/qc is as cheap as possible.
They work well enough for some applications when powered from 5 or 6v.
But depending on where that die was cut from in the wafer, may blow at 8v.
They simply don't meet the ST spec.
Most of them that do have a datasheet claim a max working voltage of 15v
as per the original ST part.
There are exceptions, claiming a max working voltage of 12v, absolute max of 15v.
The WX does not have a datasheet.??
It does not have a spec and might be doing anything it darn pleases.
That's my take.
Jerry, KE7ER
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On Sat, Jun 23, 2018 at 08:18 am, Arv Evans wrote:
It appears that there are multiple versions of the TA2822 audio amplifier, by
several different manufacturers.??
Some are rated 3V to 15 or 16V and others are 1.8V to 12V.? But that doesn't
explain why some apparently have no safety voltage range above the rated
voltage.? Maybe when they say Maximum Voltage = 12V they really mean 12V.
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Remi F1MQJ-
If power consumption is a problem, there are regulator boards that can be had/made that use a torrid to buck-boost the voltage. Much higher in efficiency than a 7805. I have heard a claim of 95%.? The circuit is basically an oscillator at the input voltage that the oscillators' output is rectified/filtered to create a new voltage output.
#2. disable the back-light of the display. Or the entire display when not looking at it. It is only an output and not interactive except to provide information. You should be able to tune around without it for short periods of time. DPDT Center off switch - display- off-? display with back light.
#3. QRP - by definition is transmitting LOW power. Not Low power consumption of the transceiver.? Comparing a 1950's 100 watt station (tubes) to a modern rig today, certainly uses less power at the mains. Likewise true low consumption minimalist transceivers are usually 1 band, CW only- crystal controlled.
?????
#4. Like you, I appreciate QRP operation and years ago used a K1SWL 40M QRP rig, that worked nicely in my sleeping bag as, frequency read out was in CW, it's only mode. My mess kit weighed more than that rig, headphones and key. True backpacker's rig. No longer made, also came in a 30 meter version.
#5. Perhaps a Radunio with cw audio readout will be instituted by others.? "PROGRAMMING ARDUINO" by Simon Mark ISBN 978-0-07-178422-1 has information on a CW sketch, albeit it converts ASCII to a flashing LED. But a good basis. Further application would be visually impaired hams. It could be a Raduino without the display- a Plug in.. or a variant of #2 above.
Regards from Kansas,
Larry W8LM
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Re: Understanding Spurious Emissions
Hi! Farhan and others,
I feel spurii are result of the first mixer being over driven by a large margin. A rough estimate indicates that the 45MHz input to the? 1st mixer is in vicinity of 0 to +1 dbm. This appears to ten times more than the required? level of -10dbm.
I have considered following losses and gain in the reverse transmit path:
Bal mod out put -17dbm loss in pad? ? ? ? ?3 db Loss in 12MHz XF + matching transformers 3 +2 = 5db Gain in 12MHz TIA? 20db Loss in second mixer 7 db Loss in 45 MHz filter and matching transformer 5db Gain in 45MHz TIA 18db
Loss in chain 20db , gain in chain 38db.? Signal at first mixer = -17 + 18 = = + 1dbm
In real world figures may vary a bit or I maybe missing something.??
Rahul VU3WJM
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Re: Blown (socketed) TDA2822?
It appears that there are multiple versions of the TA2822 audio amplifier, by
several different manufacturers.??
Some are rated 3V to 15 or 16V and others are 1.8V to 12V.? But that doesn't
explain why some apparently have no safety voltage range above the rated
voltage.? Maybe when they say Maximum Voltage = 12V they really mean 12V.
Arv
_._
On Fri, Jun 22, 2018 at 11:30 PM Jerry Gaffke via Groups.Io <jgaffke= [email protected]> wrote: You think the WX might be a repackaged TA2822D meant for the SOIC8?
I doubt it.
I think the WX is a cheap copy that simply doesn't meet the 15v absolute max spec
We had reports that there are clones of the TDA2822 (not necessarily the WX)?
that blow when given a supply over 7 or 8 volts.? (Some club project in England)
Didn't have to be putting out significant power to blow.
As I recall, some of the WX failures happened instantly, and all struck me as consistent
with too much voltage for it to handle.
The SOIC datasheet you point to has the same 15v absolute max spec
that the DIP part does.
The primary differences I see between the SOIC and DIP datasheets from ST
have to do with power dissipation, possible that ST was using the same die in both
but the SOIC simply can't deal with the heat.
Failure mode on the SOIC would be due to?overheating under load and take a bit of time.
I don't think that is what we were seeing with the WX.
?
But I'm just guessing.
Could be proven wrong.
Jerry
On Fri, Jun 22, 2018 at 09:59 pm, Raj vu2zap wrote:
You missed my point Jerry. I am not suggesting 2822D. Please see
the spec sheet I attached. It is a lower power version of tda2822.
I think that die is being repackaged as TDA2822 in 8 pin DIP. It cannot
take the load and blows up.
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Joel Caulkins/N6ALT
Don, ND6T
Skip Davis