I've just released a video on my channel based on your video here. The signal tracer is working well and the next step will be the making of your active probe. Many thanks for the knowledge that we get on your channel.
MrDubje Yes forgotten how much I enjoy building kits. Sometimes nice to just switch off and not have the pain an cost of ordering all the separate parts and designing myself. Because I don’t really do electronics as a day job now it good to get some soldering practice.
Nice kit build Chris and already it’s saved you a lot of time fault finding. I use my homemade tracer all the time. Well done finding that dry joint. I suppose you could have connected the other probe to the wiper of the volume pot and stuck 1Khz up it so you could hear a tone rather than hash. I look forward to many more probing videos. Cheers Graham
Radiocruncher Hi Graham If you get a minute spare we are trying to help a fellow radio dabbler get his kit radio going. My friend Clay would appreciate any advice. You know a lot more about radio than me so be nice to help the fellow out if we can . thanks Regards Chris, follow link ua-cam.com/video/c_ysLO0ouFU/v-deo.html.
Vintage Electronics Geek Hi Jack. You may already own a signal tracer they are more popular in the USA than the U.K. I would definitely recommend getting one. I like the tube HealthKit.
@@allthegearnoidea6752 most of the kits I have built I will probably never use especially the led based ones! But making the kit is more enjoyable than the final product a lot of the time
Normally this type of board has a coating to stop oxidation of the copper bads. Acetone will clean it off then I use a thin flux over the pads before starting to solder. I make my own flux for through hole components.
Barry Mayson No that’s not correct boards are not coated except for solder resist and perhaps conformal coating after production. Kit boards like this just oxidise unless flash coated in gold. Flash coating is not normally done as it adds cost. Thanks for watching and great comments regards Chris
thanks for this video i just subscribed, new to electronics,fascinated in diagnosing and trouble shoot. like how you explained what you were doing at each step. amazing that you found a loose/bad soldering joint,i think that happens to me as well. i only have a fluke mm,think i will get this velleman as it looks relatively easy to put together,doesnt even need a case, and i can learn signal tracing and signal injecting. look forward to your modification of this velleman in future. john
Hello John thank you very much for the nice comments glad you found the video interresting. I would recomend the Velleman kit is a nice little project. Check the RadioCruncher channel he uses a signal tracer a lot for radio repairs. Nice to hear new people are coming into the hobby it great fun even if we get it wrong its all part of the fun. Best regards Chris
Great Job Chris Love Makeing Kits Haven't Made Any Since I Made a Few Sinclair Kits Back In The Day The Cambridge Calculator,Black Watch Kit And The Micro Matic Radio, Will Have To Invest In a signal tracer /injector For If Work On My Roberts And Hackers..Regards mike.
raceingdemon6464 Hello Mike thanks for the nice comments and glad you enjoyed the signal tracer build. I am just building a kit radio at the moment and having great fun. I would really recommend getting one from eBay or Amazon. I will be upload a video on this soon. Enjoy your Christmas Regards Chris.
Hello, beautiful instructive video, I wish I had your skills! I also purchased the Velleman K7000 and assembled it. I wanted to ask you, since I am inexperienced, if you could give me some indication on where and which signal injection and extraction probes to buy. Thank you
I don’t think there is really much on the market to choose from. So realistically just buy what you can and enjoy working it out regard performance. Thanks for watching regards Chris
The Defpom's Repair Channel That was my first guess, but found a host of bad joints and repaired three large cracks in the PCB. Do you normally re cap these radios as a matter of course. It’s a well beaten radio not sure if it would be worthwhile spending the money on. I was just going to try an realign to see if it meets factory spec etc and if it does just leave it. The squelch is defective but not investigated it yet. Appears to take quite a lot to kill a CB radio, it’s annoying that bought three spares and repair and the all work.
AllTheGearNoIdea - if it is a quality radio, and is worth future proofing then I will recap it, but otherwise I will only recap the faulty ones, or if I am having trouble narrowing down a fault (80% of the time it is a bad cap)
The Defpom's Repair Channel Hi scott. Great advice I think you have confirmed what I was thinking. It a pretty crappy example of the species. Regards Chris
Hi Chris. What is that demodulator probe? Never seem to find them online. Like the steam train soundtrack at 26:02. I could listen to that all night without getting board!
Simon Spiers Hi Simon I think the one I bought came from RS, but just has a look and they don’t list it now it over ten years old. You can get them online from various places www.reichelt.com/de/en/demodulator-probe-testec-de-112-p32427.html?ARTICLE=32427&&r=1. Unfortunately about 5 minutes before you posted the comments I dump the manual in the outside bin with a load of food wast on top. I will dig through later.
Simon Spiers Hi Simon, If you get a minute spare we are trying to help a fellow radio dabbler get his kit radio going. My friend Clay would appreciate any advice. thanks Regards Chris, follow link ua-cam.com/video/c_ysLO0ouFU/v-deo.html.
Ahh the maxcom 4E and similar, i would have probed the volume control to make sure the mc3357 down mixer to 455khz/demod/squelch chip was still alive, they do die do die do die Oops got stuck in a loop there :-D The tx audio in that radio has its own quad op amp circuit, i cant remember the number but its the dip in front of the rx audio power amp ta7205 or similar. If the radio is actually going in to tx, the output tranny may be toast, too many people run radios into a horrible swr, silly buggers lol. Sorry for the waffle, i used to repair c.b's as well as lots of other crap. Mr defpom is a super wizzbang at repairing/designing electronics, worth subbing to the old git ha ha joking :-D
zx8401ztv Thanks for the tips not really dug into the radio yet. Just spent an hour this morning repairing some large cracks in the PCB and resoldering the case to the cab PCB. It going into transmit now and drawing current but not had it on the analyser yet. I am not sure if repairing this will be a video sometimes i just want to crack on etc. . Noticed the squelch is not working but not investigated it yet. If your interested the circuits are easily available for download so I will add a link to the show notes later. Ok off out into the garage now to drill some holes for the RF matching pads in those aliminium boxes I bought last week.
The squelch comes from the mc3357 if i remember right, sound driven type. Don't expect too much from the c.b, very cheap design, oddly quite reliable untill big hairy truck drivers ram 24 volts up it's bum lol. Thanks for the diagram offer, but i do have it in many disguises on paper :-D. No i don't expect anything, it's your hobby, we are just pen pals with an addiction to drinking tea, well i am anyway lol.
Dynamic memory mulitplexing if i remember right, A0-A7 then A8 - A15. The memory is shared between display and program, 16384 to 23295 is display and 23296 to 32767 is system use, 32768-65535 is normal uncontended ram. It has been 20 years since i used to repair speccys, so forgive me if i have the wrong end of the stick :-)
That signal breakthrough is annoying, I did the same trick as you did with the extra earth when I built mine a few years ago but you can still hear it. I was thinking about sticking a FET on the input side funnily enough, I bought some MPF102s ages ago for the very porpoise. The injector gives a very clean sine wave I must say, mines running about 900hz. Velleman do or did a simple function generator kit I think. Regards _ Andrew
Andrewausfa yes adding a FET input to the probe would be good. You really want a really fast rising square wave for the input this will be rich in rf harmonic content that can be picked up and demodulated by the input detector probe. That would be better than the sine wave
Andrewausfa Hi Andrew If you get a minute spare we are trying to help a fellow radio dabbler get his kit radio going. My friend Clay would appreciate any advice. You know a lot more about radio than me so be nice to help the fellow out if we can . thanks Regards Chris, follow link ua-cam.com/video/c_ysLO0ouFU/v-deo.html.
Andrewausfa - You have 553 subscribers.. I going to add myself as 554 to your channel, so the next guy/gal after me should win a prize right? :-) ha ha Merry Christmas!
I just built one of these and am trying to use it to trouble shoot an FM radio kit. The radio is doing nothing but a little hiss.I have made probes and they seem to test OK. I not sure which probe to use. Input or output or where to begin checking. Can you tell me ? I do get a tone at some points through the radio speaker. Am I correct in thinking that all Im going to hear is the tone or will I ever hear an Audio signal? Any help would be very much appreciated! Merry Christmas!
Clay Thomas it’s a bit difficult to know where to start as I don’t know your background or radio experience. This probe is really designed for audio circuits rather than the radio frequency section of you radio. The probe is basically just a small audio amplifier so if there is a detected signal of small level probe will detect it and amplify it to a point where you can hear it. The probe will also generate a 1 kHz test tone so you can inject the tone into the amplifier on the radio and you should hear the tone coming out the speaker of your radio. Have a look at some other UA-cam videos signal tracer are common so you should find some better details of how to use them than my video. Come back with more questions I will try and help you if I can. Note that the green probe I’m using is a demodulation probe so it will demodulation RF in the radio and let me test the RF sections, your simple probe will only amplify the existing audio. Regards Chris.
I am very new to the science of radio. When I bought a Mooney single engine plane last year I became much intrigued with the ADF which is an AM radio with a loop antenna for direction finding or bearing to the station. I was able to get it working by reading the original Bendix manual complete with the theory of operation and all the original wiring diagrams. I am capable of reading electrical diagrams but just starting to put together all the radio pieces. Its fascinating and Im very impressed with guys who can seemingly work on radios easily and know whats going on inside them. I built the Elenco AM kit last year and a home made loop antenna and get great reception at night. We live in south central Tennessee and I pick up New York, Chicago, Detroit, Atlanta and Houston Tx. I just finished the Elenco 108 Superhet kit and the AM side is working fine. The FM side is dead. I have checked and rechecked everything several times and cant get anything. I built the little K7000 to help me trouble shoot. Let me try to link up to a wiring diagram. Thanks for responding.
Never thought about the gender of a potentiometer. Now, I don't need to. Thanks Chris.
I've just released a video on my channel based on your video here. The signal tracer is working well and the next step will be the making of your active probe. Many thanks for the knowledge that we get on your channel.
Ah, velleman kits. Used to build a few, just for fun. Glad you found (one of the) the problem(s) with the CB radio!
MrDubje Yes forgotten how much I enjoy building kits. Sometimes nice to just switch off and not have the pain an cost of ordering all the separate parts and designing myself. Because I don’t really do electronics as a day job now it good to get some soldering practice.
Very interesting watching this. I bought one of those kits a while ago and not yet assembled. I can now see how useful it is. Thanks.
Merci pour cette vidéo sur le Vellman K 7000 !
Très bien ce tuto !
Thank you for this video on the Vellman K 7000 !
Very well this tutorial !
Georges MILLION Thank you for watching and leaving such a nice comment. Thanks best regards Chris
Nice kit build Chris and already it’s saved you a lot of time fault finding. I use my homemade tracer all the time. Well done finding that dry joint. I suppose you could have connected the other probe to the wiper of the volume pot and stuck 1Khz up it so you could hear a tone rather than hash. I look forward to many more probing videos. Cheers Graham
Radiocruncher Thanks Graham I got the idea from you. Clearly when it comes to probing you are the master and I am a humble apprentice.
Radiocruncher Hi Graham If you get a minute spare we are trying to help a fellow radio dabbler get his kit radio going. My friend Clay would appreciate any advice. You know a lot more about radio than me so be nice to help the fellow out if we can . thanks Regards Chris, follow link ua-cam.com/video/c_ysLO0ouFU/v-deo.html.
I'm stoked to be one of the 555. We should make a Tee shirt "The 555 Club" Awesome video! Regards Dan.
Full Wave Recked I quite like that idea. I wonder if it’s possible to turn off new subscribers. Keep like a members club one in one out LOL
@@allthegearnoidea6752 the in and out could be determined by a 555 chip somehow... lol!
Great build and great demo of usage, thanks mate! ~Jack, VEG
Vintage Electronics Geek Hi Jack. You may already own a signal tracer they are more popular in the USA than the U.K. I would definitely recommend getting one. I like the tube HealthKit.
I love building kit just to relax in the evenings :)
Josh lever me to, forgotten how much I enjoyed it. There’s loads of ridiculous cheap kits from China on eBay to fill a few evenings. Happy days.
@@allthegearnoidea6752 most of the kits I have built I will probably never use especially the led based ones! But making the kit is more enjoyable than the final product a lot of the time
Josh lever absolutely couldn’t agree more. Plus LEDs are still cool.
Very enjoyable video. Thanks for sharing.
Normally this type of board has a coating to stop oxidation of the copper bads. Acetone will clean it off then I use a thin flux over the pads before starting to solder. I make my own flux for through hole components.
Barry Mayson No that’s not correct boards are not coated except for solder resist and perhaps conformal coating after production. Kit boards like this just oxidise unless flash coated in gold. Flash coating is not normally done as it adds cost. Thanks for watching and great comments regards Chris
thanks for this video
i just subscribed, new to electronics,fascinated in diagnosing and trouble shoot.
like how you explained what you were doing at each step.
amazing that you found a loose/bad soldering joint,i think that happens to me as well.
i only have a fluke mm,think i will get this velleman as it looks relatively easy to put together,doesnt even need a case, and i can learn signal tracing and signal injecting.
look forward to your modification of this velleman in future.
john
Hello John thank you very much for the nice comments glad you found the video interresting. I would recomend the Velleman kit is a nice little project. Check the RadioCruncher channel he uses a signal tracer a lot for radio repairs. Nice to hear new people are coming into the hobby it great fun even if we get it wrong its all part of the fun. Best regards Chris
Just noticed I have 555 subscribers. I like that number😀
Great Job Chris Love Makeing Kits Haven't Made Any Since I Made a Few Sinclair Kits Back In The Day The Cambridge Calculator,Black Watch Kit And The Micro Matic Radio, Will Have To Invest In a signal tracer /injector For If Work On My Roberts And Hackers..Regards mike.
raceingdemon6464 Hello Mike thanks for the nice comments and glad you enjoyed the signal tracer build. I am just building a kit radio at the moment and having great fun. I would really recommend getting one from eBay or Amazon. I will be upload a video on this soon. Enjoy your Christmas Regards Chris.
Hello, beautiful instructive video, I wish I had your skills! I also purchased the Velleman K7000 and assembled it. I wanted to ask you, since I am inexperienced, if you could give me some indication on where and which signal injection and extraction probes to buy. Thank you
I don’t think there is really much on the market to choose from. So realistically just buy what you can and enjoy working it out regard performance. Thanks for watching regards Chris
Ok thanks, so any demodulation probe from an oscilloscope or signal generator is fine?
@ 24:00 I have seen many external speaker jacks fail, I have repaired/replaced lots of them.
The Defpom's Repair Channel That was my first guess, but found a host of bad joints and repaired three large cracks in the PCB. Do you normally re cap these radios as a matter of course. It’s a well beaten radio not sure if it would be worthwhile spending the money on. I was just going to try an realign to see if it meets factory spec etc and if it does just leave it. The squelch is defective but not investigated it yet. Appears to take quite a lot to kill a CB radio, it’s annoying that bought three spares and repair and the all work.
AllTheGearNoIdea - if it is a quality radio, and is worth future proofing then I will recap it, but otherwise I will only recap the faulty ones, or if I am having trouble narrowing down a fault (80% of the time it is a bad cap)
The Defpom's Repair Channel Hi scott. Great advice I think you have confirmed what I was thinking. It a pretty crappy example of the species. Regards Chris
Hi Chris. What is that demodulator probe? Never seem to find them online. Like the steam train soundtrack at 26:02. I could listen to that all night without getting board!
Simon Spiers Hi Simon I think the one I bought came from RS, but just has a look and they don’t list it now it over ten years old. You can get them online from various places www.reichelt.com/de/en/demodulator-probe-testec-de-112-p32427.html?ARTICLE=32427&&r=1. Unfortunately about 5 minutes before you posted the comments I dump the manual in the outside bin with a load of food wast on top. I will dig through later.
The one I have is made but PKM in Germany. Model PDM 781
Simon Spiers Hi Simon, If you get a minute spare we are trying to help a fellow radio dabbler get his kit radio going. My friend Clay would appreciate any advice. thanks Regards Chris, follow link ua-cam.com/video/c_ysLO0ouFU/v-deo.html.
I suppose the video is to show the performance of the k7000 velleman, but you didn't , why???
rodolfo gomez Thanks great comment. Stay safe regards Chris
Ahh the maxcom 4E and similar, i would have probed the volume control to make sure the mc3357 down mixer to 455khz/demod/squelch chip was still alive, they do die do die do die Oops got stuck in a loop there :-D
The tx audio in that radio has its own quad op amp circuit, i cant remember the number but its the dip in front of the rx audio power amp ta7205 or similar.
If the radio is actually going in to tx, the output tranny may be toast, too many people run radios into a horrible swr, silly buggers lol.
Sorry for the waffle, i used to repair c.b's as well as lots of other crap.
Mr defpom is a super wizzbang at repairing/designing electronics, worth subbing to the old git ha ha joking :-D
zx8401ztv Thanks for the tips not really dug into the radio yet. Just spent an hour this morning repairing some large cracks in the PCB and resoldering the case to the cab PCB. It going into transmit now and drawing current but not had it on the analyser yet. I am not sure if repairing this will be a video sometimes i just want to crack on etc. . Noticed the squelch is not working but not investigated it yet. If your interested the circuits are easily available for download so I will add a link to the show notes later. Ok off out into the garage now to drill some holes for the RF matching pads in those aliminium boxes I bought last week.
The squelch comes from the mc3357 if i remember right, sound driven type.
Don't expect too much from the c.b, very cheap design, oddly quite reliable untill big hairy truck drivers ram 24 volts up it's bum lol.
Thanks for the diagram offer, but i do have it in many disguises on paper :-D.
No i don't expect anything, it's your hobby, we are just pen pals with an addiction to drinking tea, well i am anyway lol.
zx8401ztv ZX spectrum mux bus chip ? What all that about ?
Dynamic memory mulitplexing if i remember right, A0-A7 then A8 - A15.
The memory is shared between display and program, 16384 to 23295 is display and 23296 to 32767 is system use, 32768-65535 is normal uncontended ram.
It has been 20 years since i used to repair speccys, so forgive me if i have the wrong end of the stick :-)
ooops i was blind again, my label on youtube, it sunk in lol, sorry.
It doesnt come with a probe that sucks
Ron Thompson No probe but I think the instructions do show a drawing for one but they don’t include the components and that sucks
@@allthegearnoidea6752 yeah zI hate oncompletes kits too
That signal breakthrough is annoying, I did the same trick as you did with the extra earth when I built mine a few years ago but you can still hear it. I was thinking about sticking a FET on the input side funnily enough, I bought some MPF102s ages ago for the very porpoise. The injector gives a very clean sine wave I must say, mines running about 900hz. Velleman do or did a simple function generator kit I think. Regards _ Andrew
Andrewausfa yes adding a FET input to the probe would be good. You really want a really fast rising square wave for the input this will be rich in rf harmonic content that can be picked up and demodulated by the input detector probe. That would be better than the sine wave
Andrewausfa Hi Andrew If you get a minute spare we are trying to help a fellow radio dabbler get his kit radio going. My friend Clay would appreciate any advice. You know a lot more about radio than me so be nice to help the fellow out if we can . thanks Regards Chris, follow link ua-cam.com/video/c_ysLO0ouFU/v-deo.html.
Andrewausfa
- You have 553 subscribers.. I going to add myself as 554 to your channel, so the next guy/gal after me should win a prize right? :-) ha ha Merry Christmas!
I just built one of these and am trying to use it to trouble shoot an FM radio kit. The radio is doing nothing but a little hiss.I have made probes and they seem to test OK. I not sure which probe to use. Input or output or where to begin checking. Can you tell me ? I do get a tone at some points through the radio speaker. Am I correct in thinking that all Im going to hear is the tone or will I ever hear an Audio signal? Any help would be very much appreciated! Merry Christmas!
Clay Thomas it’s a bit difficult to know where to start as I don’t know your background or radio experience. This probe is really designed for audio circuits rather than the radio frequency section of you radio. The probe is basically just a small audio amplifier so if there is a detected signal of small level probe will detect it and amplify it to a point where you can hear it. The probe will also generate a 1 kHz test tone so you can inject the tone into the amplifier on the radio and you should hear the tone coming out the speaker of your radio. Have a look at some other UA-cam videos signal tracer are common so you should find some better details of how to use them than my video. Come back with more questions I will try and help you if I can. Note that the green probe I’m using is a demodulation probe so it will demodulation RF in the radio and let me test the RF sections, your simple probe will only amplify the existing audio. Regards Chris.
If you can provide a link to the radio kit it would help to see the circuit. I can maybe tell you where to probe.
I am very new to the science of radio. When I bought a Mooney single engine plane last year I became much intrigued with the ADF which is an AM radio with a loop antenna for direction finding or bearing to the station. I was able to get it working by reading the original Bendix manual complete with the theory of operation and all the original wiring diagrams. I am capable of reading electrical diagrams but just starting to put together all the radio pieces. Its fascinating and Im very impressed with guys who can seemingly work on radios easily and know whats going on inside them. I built the Elenco AM kit last year and a home made loop antenna and get great reception at night. We live in south central Tennessee and I pick up New York, Chicago, Detroit, Atlanta and Houston Tx. I just finished the Elenco 108 Superhet kit and the AM side is working fine. The FM side is dead. I have checked and rechecked everything several times and cant get anything. I built the little K7000 to help me trouble shoot. Let me try to link up to a wiring diagram. Thanks for responding.
www.elenco.com/wp-content/uploads/2017/10/AMFM-108CK_low-res-2.pdf is the manual link. Thanks.
If you scroll down to the last page you'll see a schematic wiring diagram.
A scope is the only way to really signal trace
Signal tracer have been used for year fault finding in radio and amplifier stages and can be better than a scope in audio applications.
Come on man, no it isn't.