#27 Troubleshooting and testing a viewers Icom IC 745

[@jaybats7865]

Great job Buddy. With all of your experience I often wonder how many thousands of dollars your clients save with your knowledge verses another less experienced technician that would take twice as long to diagnose the problem. Thanks again for the fun 73

[@scdevon]

Lousy trimmers in an otherwise fantastic radio. It seemed like every other person you talked to in the 1980s was running this radio or a Kenwood TS-440. Even with the flakey trimmers, I sure wish they made HF radios this simple and serviceable again. It's amazing how we adjust to changing technology. These radios were considered "complicated" in the 1980s. Great work! This radio has another 30 years left in it.

[@TheRadioShop]

Yep, they really skimped on the vco trimmers in these rigs. Other than that and the ram memory they are some great rigs. Thanks for the kind words my friend.

[@richardjean8044]

Great job ! I called Icom Service today they wont work on these anymore. I have three of them (one belongs to my dad), two with problems and one good. Pre-amp is bad on dads (he said its the relay), and one of mine I thought was the finals, but after watching your videos I will need to take a closer look... I have the service manual so its off to the troubleshooting bench for me. I can't part with them, it was my first rig when I got my license. Your videos gave me the nudge I needed to get working on these, Thanks very much Buddy! 73's Rich - N8PFK

[@TheRadioShop]

Good deal Richard. They are not that hard to work on at all. If you need assistants let us know.

[@richardjean8044]

Thank you, appreciate the support.

[@mikesradiorepair]

Just got to love those cheap plastic variable caps. One way to ensure future parts sales. :)

[@TheRadioShop]

+MikesRadioRepair .CBRadio Exactly. They knew these caps would fail.

[@jstrunck]

Looking forward to watching for follow up vids! I might be able to fix my 745 to replace the trimmers and realign my 745 also. Thanks Again! John

[@grantfullen9559]

Thanks for making these videos . Good job.

[@TheRadioShop]

+Grant Fullen Grant, thanks the kind words. Glad you are liking them my friend.

[@OrbiterElectronics]

Another interesting troubleshooting job Buddy. Thanks for sharing another great video my friend. Cheers John

[@TheRadioShop]

+orbiter8 (John) Always happy to see you stop by John. Thanks for the kind words and have a great day :)

[@duskwarby7964]

Am a hands-on EE, and have recently acquired a 745... You most definitely have a new follower here. Sir ... call me Totally Impressed with your techniques and videos (W3RPZ Dave)

[@TheRadioShop]

Thanks for the kind words Dave. I really enjoy working on old and new equipment. Those 745 are some really nice easy to work on rigs. You will like it. Thanks for following my channel.

[@jonmullins8460]

I have a Kenwood TS140S with a similar issue. On some bands it will sound dead until I key the mic, then it starts receiving. Time to start checking around the VCOs

[@TheRadioShop]

That is the VCO trimmer issue for sure.

[@jonmullins8460]

Well that will be my next project. After I get this old Zenith G725 AM/FM that my daughter gave me for Father's day back to life. Waiting on caps for that.

[@heathwhittle4514]

Love the videos! Thank you so much !

[@TheRadioShop]

Thanks

[@TRXLab]

Hi Buddy, great repair. Always this crappy caps :-( Take care 73

[@TheRadioShop]

+TRXBench Hi Peter, Thanks for stopping by my friend. You got it, more crappy ones. Well, at least it is an easy fix :)

[@edmcg1918]

Buddy, your videos are the best. Thank you for sharing your knowledge and experience. could you comment on the feasiblility of using 100v 5-20 pf ceramic caps Still available from Digi-Key) in place of the original 6 and 12pf caps?

[@TheRadioShop]

Thanks for the kind words. About those trimmers, hard to make a comment on yet. I have not tried them. The wide range worries me a bit using these in a vco section. I will have to get some to see.

[@dylanschulz2404]

Would that cause slightly rough receive audio? I just got my friend's running last week and was working some 12 and 10 meter SSB and FM with great results. Now all of a sudden 10 and 12 sound a bit rough but all other bands sound fine. Thank you so much for your videos and I joined your Patreon!

[@PapasDino]

Glad your thumb is healing, I would cringe when I saw it knowing how uncomfortable it must have been at first. Look forward to the continuing saga of the 745 series fixes! I'm guessing you sourced the 24pF cap that wasn't available from Icom? 73 - Dino KL0S

[@TheRadioShop]

+Dino Papas Yes, that thumb has been in pain for several months now. Cracked the bone right on the end. But much better now :)Yes, Icom no longer has the 24pF cap. But a little over a year ago I bought out a guy that was getting out of repair. When I checked I have a good bin full of standard NPO caps and some "blue" caps with tighter tolerances. So should be ok on that. Still throwing a few ideas around on the bench for the ram board. Going to be bit of work. Thanks for coming by my friend. 73 Buddy

[@stevensaylor9430]

Great job as usual. I know it's been some time since this repair, but wondering if you still work on the 745's?? I have one with same problems as this one. Please let me know and thanks for doing what you do.

[@TheRadioShop]

The problem at the moment is sourcing the 12 pf trimmers for the VCO. They have been discontinued. I have not found any to replace them with.

[@RedTech443]

Do you by chance still repair the IC 745 for people? I have had some really bad luck with some repair shops, sent out 2 times and still not working. I no longer have transmit after receiving from the repair shop on the latest repair for having the vco trimmers replaced.

[@llaymard]

Really enjoy your videos. They are clear and straightforward. I have an old IC-745 and your programs encouraged me to take off the top. I am not skilled in electronic troubleshooting. I made a rookie mistake of unplugging the internal speaker. Now I can't remember where it was connected. I've looked all over the boards on the top of the unit and can't find a connector that looks like a proper fit. Can you help me with this with some point and fix directions. Thanks so much.

[@TheRadioShop]

Thanks Lou for the kind words. Sure, I will give you a link to my site. Scroll to the bottom and see the picture with the circled connector. Front left hand corner is where it goes. Link below.

[@TheRadioShop]

gokarters.com/smf/index.php?topic=2515.new#new

[@stevewarner8880]

I had my 745 out camping this weekend in my “to go” box. It developed a problem that I could get full output on CW but none on SSB using the PTT switch on the mic. If I pushed the VOX switch, I would get full output on SSB without using the PTT. Ideas?

[@michaelpapadakis3937]

Thank you kindly,sir

[@TheRadioShop]

And thank you

[@philbrown6393]

Hello Buddy really enjoy watching your very informative videos would you be able to do one or two on an Icom IC-751A Phil

[@TheRadioShop]

Hi Phil and thanks. I do not get many 751's in for some reason. Did have one about 2 years ago that a friend bought at a ham fest. When one does come in I will be sure to video it.

[@radiobigman47]

i love it keep the videos going if you run out of things to work on i got some things for you

[@TheRadioShop]

+kc9kuh Thank you for the kind words. Sometimes I have to wonder what I am going to do a video on, then something just happens to show up :)

[@michaelpapadakis3937]

i have a ic745 with low tx on all bands. what should i look for?

[@TheRadioShop]

Hi Michael. Well you should start by checking the level of the mixer board. make sure all voltages are correct, From there go to the LPF board and then to the PLL board. That should get you started.

[@warplanner8852]

Buddy, commenting over a year late on this, but why on earth would you want to reverse engineer the Piexx board? They are good, reliable, and the company stands behind them. They were made to replace Icom's P. O. S. boards with their battery backed up RAM with the potential to fail and lose the radio's firmware.

[@TheRadioShop]

hi, commenting over a year is fine :-) Why would I want to reverse engineer the Piexx board? I would not want to . I agree with what you said about them. They are fine units. Build my own board to learn more about its operation is what I am suggesting.Good question.

[@MsTonyhunt]

Hi, I've watched your channel for some time and find them very informative. Regrettably the first half is ruined because your voice is virtually inaudible

[@MsTonyhunt]

Above the radio background. noise, far too loud.

[@TheRadioShop]

+Tony Hunt Tony, First thank you for watching the videos. Second, Thanks for this feedback. I did not notice a problem on the audio in the preview. But I was using head phones and have bit of a scratchy throat. Sorry about the audio quality and letting me know. Will get it right the next time.

[@TheRadioShop]

+Tony Hunt Yes I am seeing what you are saying now. I really need a new camera with a audio input jack. I just listened to it with the pc speakers and it is terrible.

[@MsTonyhunt]

+The Radio Shop I suspect it's a simple reason. Wearing headphones, as I do, means the background noise is reduced substantially (why we use headphones), if you reduce the volume to them, you will notice background noise during recording much more.

[@Дава-м9к]

Здравствуйте! При каком напряжении батарейки -- мы её меняем ?