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I forgot to ground the black wire on the arduino. When I plugged in the power D7 started smoking. I pulled the power grounded the black wire (one next to the brown) then tried again and it started smoking again. Do yall think changing D7 will fix it or did I really screw up? I was trying to find d7 in the circuit diagram to see what it is but it's like looking for waldo. 
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Bottom left corner of schematic. Are you sure you don't have the
power hooked up backwards?
On 10/20/2017 10:38 PM, Barrett O
wrote:
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I forgot to ground
the black wire on the arduino. When I plugged in the power D7
started smoking. I pulled the power grounded the black wire (one
next to the brown) then tried again and it started smoking again.
Do yall think changing D7 will fix it or did I really screw up? I
was trying to find d7 in the circuit diagram to see what it is but
it's like looking for waldo.
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D7 is in the VCC line right next to the relay K1.
Check your wiring. It seems likely that you applied
12v to the Nano (or reversed the polarity), which probably fried it.
If K1 coil is open, then the 12c would be applied
directly to D7 as the load at that point. Maybe that's
what took out the diode...
john
AD5YE
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Wow I actually did have the voltage backwards. I was trying out this down converter with 4 18650 batteries and they have the negative out labeled as positive. Does anyone know the specs on that diode??
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Nothing special, just a 4148 I believe.
On 10/20/2017 11:26 PM, Barrett O
wrote:
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Wow I actually did
have the voltage backwards. I was trying out this down converter
with 4 18650 batteries and they have the negative out labeled as
positive. Does anyone know the specs on that diode??
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It's a SMT 1N4148. It can take about 1.5A forward current
before overheating and giving up the ghost. It is a cheap and common
diode if you have to replace it. If the reversal was short enough, most or all
of the other parts survived, except maybe the Nano. Check it very carefully
with a meter to know what voltage is where. 12v on the Nano will destroy it.
There seems to be some confusion about + and - and the wire colors.
In the USA black is the "hot" lead for AC VOLTAGES, white is the neutral or return
and green is the common ground. Traditionally, for DC VOLTAGES, red is the
positive lead and black is the negative lead (maybe there is a green for ground).
Of course, homebrewers use whatever is handy...
I am not sure what the EIA standard is but probably brown and purple are involved.
Be careful; the BITX convention is not standard.
The best fix is a 1N4004 diode or better at the source point of all your voltages.
That way a reverse voltage is rendered harmless to the board being examined.
Been there, done that.
john
AD5YE
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12v on the Nano will destroy it.
Thats confusing unless I'm missing something. The wiring diagram shows +12v to orange wire on raduino and black to ground
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The Raduino has a 5V regulator to drop the voltage for the Nano soldered
in.
Raduino takes the same 12V that the BITX40 takes but brings it down to
5V.
By mistake if you connect or a oops moment put 12V on 5V line then its a
goner.
Thats what John is saying!
Raj
At 21/10/2017, you wrote:
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- 12v on the Nano will destroy it.
Thats confusing unless I'm missing something. The wiring diagram
shows +12v to orange wire on raduino and black to ground
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Looks like D7 is a snubber diode for the ?relay K1.? There's also a snubber diode D8 on relay K2 (near the blue trimmer RV1).
On Fri, Oct 20, 2017 at 9:38 PM, Barrett O <ogebarrett@...> wrote: I forgot to ground the black wire on the arduino. When I plugged in the power D7 started smoking. I pulled the power grounded the black wire (one next to the brown) then tried again and it started smoking again. Do yall think changing D7 will fix it or did I really screw up? I was trying to find d7 in the circuit diagram to see what it is but it's like looking for waldo.
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Ok it's clear now. Thanks for the help I have a lot to learn. When I get a chance I will change that diode and try again.?
On Oct 21, 2017 6:01 AM, "Larry Smith" < 815cpu@...> wrote: Looks like D7 is a snubber diode for the ?relay K1.? There's also a snubber diode D8 on relay K2 (near the blue trimmer RV1).
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12V *anywhere* on the Nano will destroy it! though the A... and D... leads are the most susceptible.
D7, with C130, is *supposed* to be a snubber for K1's back-emf on release of PTT, but is only that accidentally. Its top-layer track from the Anode goes to a 'via' down to the bottom-layer ground-plane, making it mainly a polarity-protector if you fit a fuse. I've excised the plane around the via, cleaning that off to create a pad which then takes a short jumper to K1.9. That gives it its intended purpose. On the diagram, delete the ground and place it below C130A (where is that on the board? is it really there?), disconnect the line to C130 and connect that to the *other* side of C130A (= K1.9).
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12V *anywhere* on the Nano will destroy it! ? Well that¡¯s not strictly correct.? There is one exception.? Although it¡¯s apparently not connected in the Raduino configuration the Vin pin on the Nano goes to a voltage regulator that can take an input of up to a typical value of 15 v.? Mike K5ESS ?
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From: [email protected] [mailto:[email protected]] On Behalf Of Dexter N Muir
Sent: Saturday, October 21, 2017 13:54
To: [email protected]
Subject: Re: [BITX20] I made a mistake ? 12V *anywhere* on the Nano will destroy it! though the A... and D... leads are the most susceptible. D7, with C130, is *supposed* to be a snubber for K1's back-emf on release of PTT, but is only that accidentally. Its top-layer track from the Anode goes to a 'via' down to the bottom-layer ground-plane, making it mainly a polarity-protector if you fit a fuse. I've excised the plane around the via, cleaning that off to create a pad which then takes a short jumper to K1.9. That gives it its intended purpose. On the diagram, delete the ground and place it below C130A (where is that on the board? is it really there?), disconnect the line to C130 and connect that to the *other* side of C130A (= K1.9).
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Thanks Mike.
... *anywhere* but the power pins: VIN, 5V, GND, (REF, 3V3?) ...
Not sure of those last 2, they may be intrinsically protected/immune. :)
For my part, I'm wary of ESD anywhere near stray wiring, dangling bits ... that's what tripped me up - a brain-fade that led to a banjaxed Raduino.
73 ...
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You're probably right.?
But I would not count on a $2 Nano clone dealing with 12v at vin.
Depends on what regulator these clones have.
Some cheaper regulators may not be good beyond 5v.
And at 12v it will be dissipating a bunch of power,
if the regulator does not incorporate a thermal shutdown mode it will be toast.
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On Sat, Oct 21, 2017 at 07:42 pm, K5ESS wrote:
Well that¡¯s not strictly correct.? There is one exception.? Although it¡¯s apparently not connected in the Raduino configuration the Vin pin on the Nano goes to a voltage regulator that can take an input of up to a typical value of 15 v.?
?
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?
Certainly forget the Chinese Nano clones
working much above 9V despite many sellers saying they're good for 12V and even
15V.
I had several release the magic smoke
when running them on 12V as the regulators simply popped their tops before I
realised the problem was they all had rubbish regulators.
Either run with 9V maximum or preferably
go in with a good known 5V supply into the 5V in connection.
?
Dale G4IPZ
?
----- Original Message -----
Sent: Sunday, October 22, 2017 6:36
PM
Subject: Re: [BITX20] I made a
mistake
You're probably right.?
But I would not count on a
$2 Nano clone dealing with 12v at vin.
Depends on what regulator these
clones have.
Some cheaper regulators may not be good beyond 5v.
And at
12v it will be dissipating a bunch of power,
if the regulator does not
incorporate a thermal shutdown mode it will be toast.
On Sat, Oct
21, 2017 at 07:42 pm, K5ESS wrote:
Well
that¡¯s not strictly correct.? There is one exception.? Although
it¡¯s apparently not connected in the Raduino configuration the Vin pin on
the Nano goes to a voltage regulator that can take an input of up to a
typical value of 15 v.?
?
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Dale me ol' Chin-wah, commiserations - though if the rest of the chip survives you'll have a ready stock? of Nanos to hand! That flaky reg is the reason for the Raduino's 78LM7805 regulator - that and the Nano's current drain being either too close to or over the max spec of a 78L05.
p.s. I've taken my 7805 to the other face of the PCB for heatsink clearance and accessibility. It allows me to sit stuff close to that side of the Raduino
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?
Nope they didn't survive because the
failure of the regulator?meant that, when they blew, they went short
circuit and slammed full 12V onto the Atmega.
The ones that I have had fail were all
fitted with supposedly genuine (ha ha ha )?AMS1117-5 5V versions of the
regulator.
Luckily the problem was dealt with by me
before the product went to the client by the simple expedient of kludging a
better 5V supply and ignoring the Nano?regulator completely.
As an aside I puchased a few
sacrificial?batches of Chinese AMS1117-5 regulators and found that, on
test, less than 50% were capable of handling more than 9V input
safely.
Some manufacturers claim an input of
<=12V while other claim 15V.
The joys of the game.
?
Dale G4IPZ
?
?
----- Original Message -----
Sent: Sunday, October 22, 2017 9:24
PM
Subject: Re: [BITX20] I made a
mistake
Dale me ol' Chin-wah, commiserations - though if the rest of
the chip survives you'll have a ready stock? of Nanos to hand! That flaky
reg is the reason for the Raduino's 78LM7805 regulator - that and the Nano's
current drain being either too close to or over the max spec of a
78L05.
p.s. I've taken my 7805 to the other face of the PCB for heatsink
clearance and accessibility. It allows me to sit stuff close to that side of
the Raduino
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Hi Dale,
I'm hopeful that maybe you got a poorly done batch of clone boards.
I'll do some more testing.
Thanks for your feedback!
73, David KB4FXC
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On Sun, 22 Oct 2017, Master Ice wrote: Nope they didn't survive because the failure of the regulator meant that, when they blew, they went short circuit and slammed full 12V onto the Atmega.
The ones that I have had fail were all fitted with supposedly genuine (ha ha ha ) AMS1117-5 5V versions of the regulator.
Luckily the problem was dealt with by me before the product went to the client by the simple expedient of kludging a better 5V supply and ignoring the Nano regulator completely.
As an aside I puchased a few sacrificial batches of Chinese AMS1117-5 regulators and found that, on test, less than 50% were capable of handling more than 9V input safely.
Some manufacturers claim an input of <=12V while other claim 15V.
The joys of the game.
Dale G4IPZ
----- Original Message -----
From: Dexter N Muir
To: [email protected]
Sent: Sunday, October 22, 2017 9:24 PM
Subject: Re: [BITX20] I made a mistake
Dale me ol' Chin-wah, commiserations - though if the rest of the chip survives you'll have a ready stock of Nanos to hand! That flaky reg is the reason for the Raduino's 78LM7805 regulator - that and the Nano's current drain being either too close to or over the max spec of a 78L05.
p.s. I've taken my 7805 to the other face of the PCB for heatsink clearance and accessibility. It allows me to sit stuff close to that side of the Raduino
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Well I got around to install a diode still no luck. I had some 1N914 which are supposed to be electrically the same. I ended up accidentally ripping one of the traces off that seems to lead to the relay. I drilled and installed diode. I installed annode to ptt1-2 (brown side). connected cathode side to c130. rarduino comes on. barely any noise came out of speaker even with antenna connected. then noticed c130 was smoking and melting into board. Does anybody know what capacitor I can switch that with?
Ps. If it sounds like I don't know what I'm doing it's because I don't but trying to look at the diagram and find the nearest point that it connects to solder to with the same polarity.
Barrett
KG5SSO
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C130 is a 0.1uf. It's smoking? Are you sure that's what's smoking and not something near it?
Vince.
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On 10/23/2017 10:00 PM, Barrett O wrote: Well I got around to install a diode still no luck. I had some 1N914
which are supposed to be electrically the same. I ended up accidentally
ripping one of the traces off that seems to lead to the relay. I drilled
and installed diode. I installed annode to ptt1-2 (brown side).
connected cathode side to c130. rarduino comes on. barely any noise came
out of speaker even with antenna connected. then noticed c130 was
smoking and melting into board. Does anybody know what capacitor I can
switch that with?
Ps. If it sounds like I don't know what I'm doing it's because I don't
but trying to look at the diagram and find the nearest point that it
connects to solder to with the same polarity.
Barrett
KG5SSO
--
Michigan VHF Corp.
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Raj vu2zap