#268

#radiorepair #icom 7300

[@rscelectrical7091]

Another excellent diagnosis and repair Peter, thank you for taking the time to film it.

[@TRXLab]

Thanks

[@TheRadioShop]

Nice troubleshooting and repair Peter. Cannot count the times I have seen similar issues. Thanks for the video.

[@TRXLab]

Thanks my friend! Yeah you are right, we find to many of those issues.

[@bblod4896]

With those steam powered radios? 😂 Have a peaceful Sunday.

[@montygore1200]

Hi Peter. as you know that is a dangerous circuit for the radio. For my customers I have a circuit using a optocoupler to send the amp into transmit I also put the circuit internal on older amps I repair in my shop. Thanks for the new video. You are my favorite youtube tech. Always glad to see a new video. Your videos are always pleasant to watch and informative.

[@stargazer7644]

Why would you say using a relay to key the amp is more dangerous than an optocoupler?

[@montygore1200]

Hi. To reply to your question as why not use a relay is basically 3 things. One would be the diode shorting 2 would be the relay could short and 3 the relay when the field around coil of the relay can discharge many more volts as the field collapses. Thanks for asking.

[@stargazer7644]

@@montygore1200 Your optocoupler is just as likely to short as the relay or the diode. And the purpose of the diode is to snub the voltage spike from the collapsing field.

[@DonDegidio]

Hi Peter, Nice job finding all the problems, especially the short at the male connector. Glad that circuit board trace was not so damaged you could not replace that component. Stay safe. 73 WJ3U

[@TRXLab]

Thank you, Don!

[@IZ0MTW]

Excelent investigation, root cause finding and repairing, as always. And as always thanks for sharing! Diego

[@TRXLab]

Thanks Diego

[@MicheIIePucca]

The copper ground sheath conducts heat so well, in these cases I always use a small aluminum heat sink on the ground strands so the heat doesn't melt the center wire.

[@LA9RKA]

Yet a another educational repair video, thank you very much Peter for taking the time to make this video.

[@capt.mike73ahoy14]

Good video Peter; I knew that relay in the line hanging out in mid air would drive you crazy!

[@KF7PCL]

It is pretty strange. Also a very atypical relay package

[@TRXLab]

true

[@jackofalltrades3727]

Thanks for all your hard work , I enjoy all of your videos

[@TRXLab]

Thank you Jack

[@w.rustylane5650]

Once again, a great video, Peter. I didn't realize that hooking up an external linear amplifier would involve so many components. Cheers from eastern TN

[@TRXLab]

You would only need those stuff if you have a very old PA with higher voltage on the relay line...

[@georgebodley8068]

Very poor soldering that burnt and shorting wire Lack of care when soldering .another excellent repair video well done .

[@mikefinn2101]

Peter you really are the most informative and knowledgeable person on You Tube. You are number one by far The best of the Best. You do a great service to all us Ham Radio Operators who might one day face the same issue. A real pleasure watching you even though a week late. Sorry for being a week late. Always look forward from new videos from you my friend. can't ever thank you enough you're too kind. God Bless you richly best 73s Mike

[@TRXLab]

Thank you very much appreciated !

[@n5yiz]

The 13.8v from that ACC port has always seemed a little dangerous to me. I think best to use the SEND from the phono out and use a separate, fused 13.8v tapped from the main input from now on. As shown, a lot of work if something goes wrong. Thanks for the great video.

[@snakezdewiggle6084]

But the problem was the User ! Its a bad tradesman who blames his tools. Read a book... ;)

[@KF7PCL]

Personally I also used the phono jack (seems way more convenient) but powered the relay off a 9V battery so it is totally isolated from the power system. The current draw is so low, I haven't needed to replace it yet after months of operation

[@TRXLab]

yes it is a bit tricky

[@ethanpoole3443]

I don’t understand why the Big 3 (at least) manufacturers don’t all incorporate a polyswitch (PTC thermistor basically) onto all the power out pins such that an overload is well protected against without causing any damage (they could easily have used a ~1A polyswitch here and there would have been plenty of power for even a good sized relay coil). To myself that is far better than burning out traces and components and they cost so little relative to the cost of a respectable HF radio (and especially sending out for repair). I know Yeasu radios often have a similar setup to this iCom and warn in the manual that a short, or too much accessory current, can damage the radio. This is also why I always thoroughly test all cables I make before first use and also make liberal use of heatshrink tubing (much like Peter) wherever possible to protect against shorting from frayed wires or a damaged connector (or just a bad soldering job, as seen here). Thank you so much for another great video, Peter!

[@WN8HGZ]

thanks for going back and fourth with the schematic it really helps

[@TRXLab]

Glad that you liked it...

[@notfallmed]

TNX Peter, and happy Weekend from Peter. 73

[@michaeltietzyou]

Moin, sehr schön ! Wenn ich mir die Lötstellen und das Gesamtbild des Steuerkabels, schon zu Beginn ansehe, bekomme ich Gänsehaut.

[@richardmelville5973]

Great repair. I think the relay should be re-soldered and heat shrink applied to the terminals. That thing is an accident waiting to happen!

[@stargazer7644]

I would just slip the whole thing into a large piece of heat shrink.

[@aslerunarborgersen5175]

Thank you for another interesting video, Peter. I am sure this kind of short circuit is very familiar to those of us who tried to solder the old five or six pins DIN plugs that were used on older stereo equipment. We mostly had big, clumsy soldering irons, and no microscope :) 73

[@snakezdewiggle6084]

And microphone plugs / sockets on radios in the 70's and 80's. ;)

[@TRXLab]

yes it is more or less the same plug as the old DIN plugs...

[@hectorpascal]

Anybody who has problems hand soldering SMD's should watch and learn from Peter's ideal technique shown @42:10 onwards. The key is all in the timing! To inspect home made DIN style connectors, I always use a x8 watchmaker's eye loupe. In addition, I fully agree with others that optocoupling higher voltage external circuits to transceivers via a small box, is really the safest method.

[@TRXLab]

Thanks, Hector

[@konradkubit6525]

Great repair and investigation Peter as always 73

[@RGB06084]

Great work Professor!

[@mscir]

Great video, well done, it's a real pleasure watching you work, thank you for being so thorough.

[@hoofie2002]

I made the same arrangement for my 7300 but everything us secured and lives in a little plastic box and was tested BEFORE I plugged it in. It's an expensive radio to damage.

[@marksantana4150]

ABSOLUTELY GREAT VIDEO!!! Truly. I have learned more in your videos than hours and hours odf classes. Great t work. Thank You!

[@robertrainey1728]

loved watching the repair. Not sure I understand the diagnosis so would need to watch a few times.

[@aussiedazvk4djh889]

G'day Peter. Another great video 👍

[@daveengstrom9250]

When I was a kid in school., my electronics teacher told us that electricity was made of smoke. When the smoke gets out of the wire, it doesn't work any longer. 😁

[@silvanomoreno6950]

Hello Peter, thanks for sharing this new video, its very pleasure to watch it. 73 I1WSM Silvano

[@jerrypeal653]

Another fine job.

[@regularuser492]

Unsere radiowellen Arzt is wieder am werk ! Danke Peter fuer diese lehr stunde.

[@riccardosanti3381]

Great, Great, Great. Rick

[@snakezdewiggle6084]

Good job on the pcb traces. Not an easy fix, but you got it 👍 Great video, thank you. ;)

[@tomnorman5461]

Another fine job Peter! Those connections on that external relay need to be insulated so that 13.8vdc connection never comes in contact with the radio chassis, or it will get damaged again.

[@EA8CVZ]

Gracias por el bonito vídeo. Un like para ti.....👍

[@littlebear5219]

Nice repair , which show what can happen if you don’t take care when you fit the plug

[@rjy8960]

I had to build a PTT cable for my Lab599 TX-500 which uses a GX-12 connector which also carries audio. I was REALLY nervous about this exact problem so as I'm not using that connector in this application for anything else, I decided to physically remove all of the unused pins from the GX-12 plug leaving only the GND and open collector PTT switching lines, so there is physically no way that 12V from the linear can accidentally appear on any of the other signal lines. Nice work, Peter, BTW! :)

[@SkyWire88]

Very nice video as well as fine trouble-shooting. Your customers should be required to view the video that corresponds to their repair for best understanding of the situation. Thank you.

[@TRXLab]

Most of the time they watch :-)

[@stevenmandell3385]

Well done my friend

[@stevenmandell3385]

WB4DVH

[@fredshead3956]

Yes indeed handy trick is to read manuel, and it says, its ok to use a non Icom Linear like the Ameratron 811H which i have, straight from the PTT socket, as that provides 0.5 amp and 16v, and the linear leeds 12v and 100mA, so should work, as for the Accesorie socket, you should only use an Icom amp from that socket as it provides verry little current, there is a special lead you can get for that, so i assume from that, that the Icom amplifier has a built in triggering mechanism, so as not to damage the radio, the PTT socket next to the ALC socket i am told by areliable soures comes from a relay inside the radio, whether that is a mechanical relay or a solid state relay i have no idea, i was also told if you use ssb only it works with no problem if you use carrier modes you should set the timer in the radio menu to 50mS delay...i have been using the radio and amp like that for several years and had no problems, i have never tried using the Acc socket for anything so Peters circuit diagram i dont think has anything to do with the PTT socket, only the Acc socket, so it appears to me the owner of the radio probably plugged a non Icom amplifier into the Acc socket.....from Fred g4vvq.

[@2metercrew389]

👍👍👍

[@hancecrawford]

Hi peter people want to carry out modifications they should bring it to someone like you as you know what you are doing little knowledge is dangerous

[@bblod4896]

31:46 carbon, the building blocks of life or, in this case, partial death. Dr. Peter will perform his magic on this poor radio.

[@montygore1200]

Wow I need to wait until the vieo is over to comment. Shorted at the coil after all

[@TRXLab]

all fine

[@PapasDino]

It appeared that a couple of the ground wire strands may have begun to migrate into the white insulation and the wire leading to one of the powered leads in your redone ACC connector; may have just been the way I was looking at it on my monitor. Nice fix Peter! 73 - Dino KLØS

[@TRXLab]

Hi Dino, all correct so far, but it was a red insulation. Thanks for stepping by.

[@stargazer7644]

The white insulation was the ground wire on pin 2.

[@PapasDino]

@@stargazer7644 Yeah, I caught that when I want back and looked again, thanks.

[@super-8]

Smoking cable manu-facturing

[@TRXLab]

LOL yes

[@rogerlaw8881]

Thanks for another great video, Peter! I have a 7300 so the video could come in handy sometime in the future. By the way what temperature do you set your reflow blower to?

There is a separate SEND jack next to the ALC jack specifically for amplifier purpose! Why the owner uses the ACC connector is beyond me...

[@TRXLab]

Correct

[@stargazer7644]

You can't connect that jack directly to a tube amp either - you have to use a relay. You need +12v to run the relay, and that's on the ACC connector. Now does it make sense?

[@hoofie2002]

​​@@stargazer7644 exactly what I've done on mine to drive a tube amp. Plenty of videos showing how much voltage can be across the amp PTT terminals.

[@Bass.Player]

What is the point of using an inline relay without a secondary power source to carry the load?

[@Alberto_Alletto]

Excellent video and excellent images! what camera do you use?

[@TRXLab]

a very basic Sony with Zeiss lens

[@Alberto_Alletto]

@@TRXLab many tnx !

[@hitechredneck6366]

What's the current draw on the relay supply? Might be a good idea for the customer to add an inline fuse that will prevent the choke as acting as the fuse. 🙂

[@davidhollfelder9940]

It is well known, that the PTT “pull to ground” circuit in these modern solid state radios is weak, as it can handle only very low amperage. The solution is to use an external relay box, such as the Ameritron ARB-704.

[@TRXLab]

Correct

[@stargazer7644]

Which is the same as the external relay shown in this very video. That's why it is there.

[@susanlodges48]

I suggest that you look at an inductor blown.

[@TRXLab]

well I have done that ??

[@montygore1200]

Sorry I got a little ahead of my self. I really thought the problem would have been a shorted diode or relay coil.

[@TRXLab]

No worries

[@robertbobbitt8448]

Do the man a favor and rebuild that cable properly That things an accident waiting to happen Most of the joints looked cold

[@lebrongmarlong5400]

Hi Peter, excellent video. I would like to know how I can communicate with you. 73

[@wayneambrose3234]

Peter I’m just wondering do you have anything that you’ve shot on video about alc on the 7300 I had a radio that was either hit by lightning or took a power surge I replaced a whole bunch of stuff to bring the receiver back to life and when I got that done it was working the I had Alc I had power up put everything else and then all of a sudden one day my ALC just disappeared to nothing and I don’t know what’s going on except I got checking things out and one of my antenna connecter pl259 came undone from a G5 RV and I have no antenna on it so I’m curious if I’m gonna have to check I into the final transistors or check into the drive transistors maybe you can if you’ve got a video like that try to let me figure out how to get the alc back love your videos. ❤❤❤

[@TRXLab]

Not on the IC7300, but ALC circuits are more or less the same. You may get some insights if you watch video #94

[@jimwolsiffer4397]

Great work Peter. I can't help but wonder, the value of the internal fuse? Guessing as it looks like 1 amp (yelllow)?. It makes me think the orginal fuse blew and then a higher value one was inserted ( perhaps another 1 amp blew as well...). Anyway that damage looks like a lot of current passed. On the close up of the strands shorting they look overheated at the point they penetrated the red wire. Now tell the truth, did you fix that relay wiring before you sent this back...hi hi.😅

[@KF7PCL]

If available, it might be wise to put a smaller fuse in

[@TRXLab]

The fuse is 5 A

[@jimwolsiffer4397]

@@TRXLab I would use a 1 instead. 5 amps is a bit much. That choke youbreplaced, what rating does it have? Even a 1/2 amp would be enough and future failsafe that repair. Always look forward to your lessons! I did grab that screwdriver set you reviewed, had been looking at them for a while but couldn't decide....

[@stargazer7644]

That is supposed to be a 5A fuse.

[@dondonaldson1684]

What is mind boggling is the fact that a ham authorized to run a PA at 1kW didn't check his soldering with a DMM. If he doesn't have a DMM, he has no business picking up a soldering iron. "DIY" in this case is "destroy it yourself".

[@truthfilterforyoutube8218]

Let me guess.... he was using an " Older school" power amp !

[@TRXLab]

nope

[@ptronix]

Dodgy wiring by people who should leave it to someone more capable. That relay should of course be in a nice little box, thanks Peter

[@TRXLab]

yepp a littel box would be perect.

[@charliem.9998]

yet another great video by Peter & Olaf :-) best 73s de DL6RDE / AA1KD, Charlie

[@TRXLab]

Danke Charlie

[@WN8HGZ]

well done de wb8idy

[@batman4e]

The fuse should not be replaced before finding the cause of the fault. I think the owner replaced the fuse until the trace was burnt. Also it is not good to power on units with replaced fuse before finding the fault. You should have inspected first the inside of the radio.

[@fredshead3956]

Hi Peter, i use mine with an Ameritron 811HX 800 watt amplifier, all i do is plug the PTT line into the PTT socket on the iC 7300, i've never had a problem, i have never used the remote socket, i think the 7300 has a bilit in relay to handle the load, but you could always use an external relay box....Fred g4vvq.

[@KF7PCL]

I believe the connections function identically but the keying voltage of that amp is 12V @ 100mA which should be tolerable for the rig. Many older amps had keying voltages anywhere from 20VDC (sometimes negative) up to the AC line(!), or relays without flyback diodes.

[@TRXLab]

perfect

[@stargazer7644]

The 7300 absolutely does NOT have a built in relay. You saw in this very video what the circuit is. If you apply a voltage or current above what that switching transistor will handle, it'll blow it.

[@fredshead3956]

@@stargazer7644 Ok Well the bottom line is if you use the PTT output socket it will key most amplifiers without any added circuitry, but if it doesnt then use and external relay and trigger that from ptt line...simple enough,...thats what i do, never had a problem

[@stargazer7644]

@@fredshead3956 The PTT output socket WILL NOT safely key any older amplifier with a high voltage PTT circuit or one that requires more than a couple hundred milliamps of current. That's the entire point of using the relay. So far you've been lucky enough not to have plugged your radio into one of these amplifiers. One day you'll smoke an expensive radio. Read the manual.