Topics

I'm really stuck! No Xmit Pwr. #ubitx

Latham, Chip
 

HEEELLLPPP
I assembled a Ver.3 board and everything went very well but when I measured the power out it was dead. I don't have the best power meter. I was using MFJ tuner/watt meter, set to 35 watt scale, and I was getting about a half a needle width reading. I finally found " A Diagnostic Guide for uBitx" Thank you for that document Ufi Auttorri. I measured all of the TX measurements listed in the document and every one was very close. I went back through and checked again everything seemed normal I set the bias, I had beefed up the heat sinks for the 510's a little and have a fan on them, heat sink is isolated from ground and still no transmit power. The heat sink will after a while get a little warm. I borrowed a friends QRP guys Voltmeter/ watt meter interface and measure 10 microwatts not milliwatts. It seems like something is not coupling the RF through. So I'm kinda stumped as to what to test next. 
Please Help someone, I love this radio.
73 N5FJK
Chip

ajparent1/kb1gmx
 

First are you testing in SSB or CW?

IF CW you should see power with keydown.

IF SSB you will see nearly nothing (microwatts) without audio input.  Are you putting audio in?
First places to look, Mic element is electret and the shell is ground is the mic plug and
matching connector wired correctly to pass audio?

Allison

Latham, Chip
 

CW Keydown I hear side tone no RF

Latham, Chip
 

Mic is wired correctly and can hear audio in a second rig. Audio sounds good. 
Thanks

William Cullison
 

Dumb question; have you verified 12 volts to the final. I'll be testing while hooked via USB to my computer and forget to turn on the power supply. A mind is a terrible thing to lose but I'm becoming accustomed to it.

Latham, Chip
 

Yes Sir,
Been at this a few weeks now. It has got to be a relay or something that is just not engaging all the test measurements from the document listed in the beginning were so very close. I am just not sure where or how to proceed to the next step
Thanks for responding
Chip

Arv Evans
 

Troubleshooting in a signal path usually involves in understanding how the circuit works,
determining what signal should be at each measurable point in the signal path, and making
measurements to see where the signal is too low or missing.  If sometimes helps to print
out the schematic and use a high-lighter pen to mark the signal path.  Then pencil in
obvious test points and the signal that should be present at each point.  Then you can use
this test map as a guide to determining where the trouble might be.

Arv
_._


On Tue, Jun 19, 2018 at 1:10 PM Latham, Chip <clatham@...> wrote:
Yes Sir,
Been at this a few weeks now. It has got to be a relay or something that is just not engaging all the test measurements from the document listed in the beginning were so very close. I am just not sure where or how to proceed to the next step
Thanks for responding
Chip

Latham, Chip
 

Tnx,
Arv your right. No longer have the knowledge handy to draw upon. But thanks for the great advice. I will guess my way along.
Just thought someone could hold my hand a little.
Chip

Arv Evans
 

Chip

Maybe someone could mark up the uBITX schematic to show signal path for transmit and for receive. 
Some sort of transparent color overlay might work well for those who are struggling with the technology.
This and a block diagram for receive path and a separate block diagram of the transmit path might be
useful.
Anybody...?

Arv
_._


On Tue, Jun 19, 2018 at 2:44 PM Latham, Chip <clatham@...> wrote:
Tnx,
Arv your right. No longer have the knowledge handy to draw upon. But thanks for the great advice. I will guess my way along.
Just thought someone could hold my hand a little.
Chip

Latham, Chip
 

Arv, I have an RF Levels (RMS) Showing DC levels through the RF Section with all the Values, Problem is all the values I measure are almost spot on.

w7hd.rh <w7hd.rh@...>
 

http://www.hfsignals.com/index.php/ubitx-circuit-description/
Has all that for you already.



On 06/19/2018 02:11 PM, Arv Evans wrote:
Chip

Maybe someone could mark up the uBITX schematic to show signal path for transmit and for receive. 
Some sort of transparent color overlay might work well for those who are struggling with the technology.
This and a block diagram for receive path and a separate block diagram of the transmit path might be
useful.
Anybody...?

Arv

-- 
Ron W7HD - NAQCC#7587 OMISS#9898 KX3#6966 LinuxUser#415320
Editor OVARC newsletter

M Garza <mgarza896@...>
 

If you are using the supplied BNC connector, test to make sure you are getting good contact between the center pin of the connector and the coax.  A few people had issues with that.
Just a suggestion.

Marco - KG5PRT 

On Tue, Jun 19, 2018, 4:30 PM w7hd.rh <w7hd.rh@...> wrote:
http://www.hfsignals.com/index.php/ubitx-circuit-description/
Has all that for you already.



On 06/19/2018 02:11 PM, Arv Evans wrote:
Chip

Maybe someone could mark up the uBITX schematic to show signal path for transmit and for receive. 
Some sort of transparent color overlay might work well for those who are struggling with the technology.
This and a block diagram for receive path and a separate block diagram of the transmit path might be
useful.
Anybody...?

Arv

-- 
Ron W7HD - NAQCC#7587 OMISS#9898 KX3#6966 LinuxUser#415320
Editor OVARC newsletter

Arv Evans
 

Chip 

Do you have, or can you construct a simple diode RF detector to use with your DC voltmeter?
This could be useful for tracing RF through the transmit section.

http://www.qsl.net/g3pto/probe.html

There are many variations on this design. 

Arv
_._


On Tue, Jun 19, 2018 at 3:25 PM Latham, Chip <clatham@...> wrote:
Arv, I have an RF Levels (RMS) Showing DC levels through the RF Section with all the Values, Problem is all the values I measure are almost spot on.

David Wilcox
 

The directions indicate a screened enclosure.  Some of the previous kits I have built have these power indicators included built on a perf board but no mention of enclosure.  Is an enclosure just to increase accuracy and prevent extraneous signals from overloading some of the circuits?

Dave K8WPE

On Jun 19, 2018, at 7:05 PM, Arv Evans <arvid.evans@...> wrote:

Chip 

Do you have, or can you construct a simple diode RF detector to use with your DC voltmeter?
This could be useful for tracing RF through the transmit section.

http://www.qsl.net/g3pto/probe.html

There are many variations on this design. 

Arv
_._


On Tue, Jun 19, 2018 at 3:25 PM Latham, Chip <clatham@...> wrote:
Arv, I have an RF Levels (RMS) Showing DC levels through the RF Section with all the Values, Problem is all the values I measure are almost spot on.

Arv Evans
 

Dave

A screened enclosure is nice but probably not necessary for a simple RF detector as long
as you don't have any long leads on the RF side.  The DC side is bypassed for RF and can
be either twisted wires or coax with the shield grounded.  Many who build their own RF
detector probes do so inside a plastic pen tube or build them in the open on a scrap of
PCB material.  If you do a Google search for RF Detector Probe and look at the images
you should find lots of ideas for making this piece of test equipment.  For intermittent use
it probably does not have to be a work of art.  Just something functional is adequate.

Arv
_._


On Wed, Jun 20, 2018 at 4:21 AM David Wilcox via Groups.Io <Djwilcox01=yahoo.com@groups.io> wrote:
The directions indicate a screened enclosure.  Some of the previous kits I have built have these power indicators included built on a perf board but no mention of enclosure.  Is an enclosure just to increase accuracy and prevent extraneous signals from overloading some of the circuits?

Dave K8WPE

On Jun 19, 2018, at 7:05 PM, Arv Evans <arvid.evans@...> wrote:

Chip 

Do you have, or can you construct a simple diode RF detector to use with your DC voltmeter?
This could be useful for tracing RF through the transmit section.

http://www.qsl.net/g3pto/probe.html

There are many variations on this design. 

Arv
_._


On Tue, Jun 19, 2018 at 3:25 PM Latham, Chip <clatham@...> wrote:
Arv, I have an RF Levels (RMS) Showing DC levels through the RF Section with all the Values, Problem is all the values I measure are almost spot on.

Latham, Chip
 

I will see if I can come up with a germanium diode. 
I do have a digital storage o'scope... trying .
Pay day is a ways off and I am tapped out so no more orders to the parts place this week. but have a wealth of junk just will take a bit. 
I appreciate everything that everyone is suggesting.
Thank you
Frustrated Ham
N5FJK
Chip 

Arv Evans
 

Chip  

It is possible to use your oscilloscope to trace signal flow, but the scope needs to have adequate bandwidth for the signal being viewed.  A diode detector (1N4148 diodes work fine for all but very low level testing) is faster and more convevient for transmit side signal tracing.  

Arv
_-_




Sent from my Verizon, Samsung Galaxy smartphone

-------- Original message --------
From: "Latham, Chip" <clatham@...>
Date: 6/20/18 8:35 AM (GMT-07:00)
To: BITX20@groups.io
Subject: Re: [BITX20] I'm really stuck! No Xmit Pwr. #ubitx

I will see if I can come up with a germanium diode. 
I do have a digital storage o'scope... trying .
Pay day is a ways off and I am tapped out so no more orders to the parts place this week. but have a wealth of junk just will take a bit. 
I appreciate everything that everyone is suggesting.
Thank you
Frustrated Ham
N5FJK
Chip 

Howard Fidel
 

Chip:
It you like, I can walk you through some diagnostics over the phone, provided your scope has sufficient bandwidth to use it to trouble shoot. What is the bandwidth of your scope, and do you have a 10X probe?

Howard

On 6/20/2018 11:26 AM, Arv Evans wrote:
Chip  

It is possible to use your oscilloscope to trace signal flow, but the scope needs to have adequate bandwidth for the signal being viewed.  A diode detector (1N4148 diodes work fine for all but very low level testing) is faster and more convevient for transmit side signal tracing.  

Arv
_-_




Sent from my Verizon, Samsung Galaxy smartphone

-------- Original message --------
From: "Latham, Chip" <clatham@...>
Date: 6/20/18 8:35 AM (GMT-07:00)
Subject: Re: [BITX20] I'm really stuck! No Xmit Pwr. #ubitx

I will see if I can come up with a germanium diode. 
I do have a digital storage o'scope... trying .
Pay day is a ways off and I am tapped out so no more orders to the parts place this week. but have a wealth of junk just will take a bit. 
I appreciate everything that everyone is suggesting.
Thank you
Frustrated Ham
N5FJK
Chip 


Latham, Chip
 

This will be a jumbled Mess But bear with me. I did the best I could to make this understandable and have included the PDF document as an attachment that the measurement were listed from
As I have said before you will find my measurements very close to what they should be .
Just for the fun of it I replaced the 2 IRF510 and made no difference in the out puts.
Any clues or help would be greatly appreciated. 
This is one of the boards That I'm afraid might have been shoved out the door to make room for Ver4 Farhan paid DHL shipping when I only paid for Indian Postal.
I'm sure this is not the case though. But someone may have skipped the final Transmit check.
The receive is very good 
Someday soon Maybe a Little Transmit.
I hope this makes sense to someone .

TX, PTT
50-ohm
dummy load,
no
modulation
 
 
 
Quad-1, Q20, 2N3904,
base, pin 1 2.31 VDC  My Reading 2.24 VDC
“ 18 Q20-2 1.6 VDC “ Quad-1, Q20, 2N3904, my reading 1.6 VDC
emitter, pin 2
“ 19 Q20-3 7.5 VDC “ Quad-1, Q20, 2N3904, My Reading 7.28 VDC
collector, pin 3
“ 17 Q22-1 6.7 VDC “ Quad-1, Q22, 2N3904, mine 6.7
base, pin 1
“ 18 Q22-2 6.1 VDC “ Quad-1, Q22, 2N3904, mine 5.57
emitter, pin 2
“ 19 Q22-3 11.4 VDC “ Quad-1, Q22, 2N3904, mine 10.0
collector, pin 3
“ 17 Quad-1, Q40, 2N3904,
base, pin 1 2.2 VDC , mine 2.24
 
 
“ 18 Q40-2 1.6 VDC “ Quad-1, Q40, 2N3904, mine 1.6 VDC
emitter, pin 2
“ 19 Q40-3 7.3 VDC “ Quad-1, Q40, 2N3904,mine 7.28  VDC
collector, pin 3
“ 17 Q42-1 6.7 VDC “ Quad-1, Q42, 2N3904,mine 6.64VDC
base, pin 1
“ 18 Q42-2 5.9 VDC “ Quad-1, Q42, 2N3904,mine 5.92 VDC
emitter, pin 2
“ 19 Q42-3 11.3 VDC “ Quad-1, Q42, 2N3904,mine 10.0VDC
collector, pin 3
“ 20 Q6-1 2.0 VDC Fig-5, mine 2.0VDC
section D5
Quad-2, Q6, 2N3904, base,
pin 1
“ 21 Q6-2 1.3 VDC “ Quad-2, Q6, 2N3904,mine 1.3VDC
emitter, pin 2
“ 22 Q6-3 9.8 VDC “ Quad-2, Q6, 2N3904,mine 9.6VDC
collector, pin 3
“ 23 Q90-1 3.3 mine 3.52VDC
 
 
 
“ 24 Q90-2 3.0 VDC “ Quad-4, Q90, 2N3904, mine 2.8VDC
emitter, pin 2
“ 25 Q90-3 11.3 VDC “ Quad-4, Q90, 2N3904 mine 10.0VDC
collector, pin 3
 
26 Q911-1 0.22 VDC, My Reading 0.39 VDC
 
27 Quad-4, Q911, 2N3904,
emitter, pin 1“  Q911-2 0.75 VDC “ My Reading 1.06 VDC

base, pin 2  0.75 VDC  My Reading 1.06 VDC
“ 28 Q911-3 10.9 VDC “ Quad-4, Q911, 2N3904, My Reading 11.52 VDC
collector, pin 3
“ 29 Q912-1 0.22 VDC “ Quad-4, Q912, 2N3904,  My Reading .37 VDC
emitter, pin 1
“ 30 Q912-2 0.75 VDC “ Quad-4, Q912, 2N3904, My Reading 1.05 VDC
base, pin 2
“ 31 Q912-3 10.9 VDC “ Quad-4, Q912, 2N3904, My Reading 11.5 VDC
collector, pin 3
“ 32 Q92-1 0.22 VDC Fig-5,My Reading 0.36 VDC
 
“ 33 Q92-2 0.84 VDC “ Q92, 1/4 PA driver, My Reading 1.05 VDC
2N3904, base, pin 2
“ 34 Q92-3 10.9 VDC “ Q92, 1/4 PA driver, My Reading 11.5 VDC
2N3904, collector, pin 3
“ 35 Q93-1 0.22 VDC “ Q93, 1/4 PA driver, My Reading 0.35VDC
2N3904, emmiter, pin 1
“ 36 Q93-2 0.84 VDC “ Q93, 1/4 PA driver, My Reading 1.04 VDC 
2N3904, base, pin 2
“ 37 Q93-3 10.9 VDC “ Q93, 1/4 PA driver, My Reading 11.45 VDC
2N3904, collector, pin 3
“ 38 Q96-1 0.22 VDC “ Q96, 1/4 PA driver,My Reading 0.35VDC
2N3904, emmiter, pin 1
“ 39 Q96-2 0.88 VDC “ Q96, 1/4 PA driver, My Reading 1.04 VDC
2N3904, base, pin 2
“ 40 Q96-3 10.9 VDC “ Q96, 1/4 PA driver, My Reading 11.43VDC
2N3904, collector, pin 3
“ 41 Q97-1 0.22 VDC “ Q97, 1/4 PA driver, 2N3904, My Reading 3.54VDC
emmiter, pin 1
“ 42 Q97-2 0.84 VDC “ Q97, 1/4 PA driver, 2N3904, My Reading 1.04 VDC
base, pin 2
“ 43 Q97-3 10.9 VDC “ Q97, 1/4 PA driver, 2N3904, My Reading 11.45 VDC
collector, pin 3

TX, PTT
50-ohm
dummy load,
no
modulation
44 Q94-1 3.1 VDC Fig-5, My Reading 4.7 VDC
section F3
Q94, IRF510, 1/2 PA final,
gate, pin 1
45 Q94-2 11.3 VDC “ Q94, IRF510, 1/2 PA final, My Reading 11.9 VDC
drain, pin 2
46 Q94-3 0 VDC “ Q94, IRF510, 1/2 PA final, My Reading 0.00 VDC
source, pin 3
47 Q95-1 3.3 VDC “ Q95, IRF510, 1/2 PA final, My Reading 4.82 VDC
gate, pin 1
48 Q95-2 11.3 VDC “ Q95, IRF510, 1/2 PA final, My Reading 11.9VDC
drain, pin 2
49 Q95-3 0 VDC “ Q95, IRF510, 1/2 PA final, My Reading 0.00 VDC

source, pin 3
50 U2-1 4.2 VDC “ LM78L05ACZ bias  My Reading 5.02 VDC
regulator, out, pin 1
51 U2-2 0 VDC “ LM78L05ACZ bias My Reading 0.00 VDC
regulator, gnd, pin 2
52 U2-3 10.9 VDC “ LM78L05ACZ bias My Reading 11.64 VDC
regulator, in, pin 3
 

Latham, Chip
 

Howard that would be great The Scope is a 70 Mhz and I  have a 10x probe. Its a cheap Hantek DSO5072p 
I will be available tomorrow until 5pm central standard My e-MAIL IS CLATHAM@... DIRECT PHONE IS 405-742-5278 DURING DAYTIME.