Yaesu FT-450D No TX Troubleshoot & Repair

In this video I troubleshoot and repair a no TX issue. I also try to cover some of the basics of how the DSP works in the radio. It’s quite a long video as it was not easy to locate the problem. This is a component level electronic fault finding and repair video. Please feel free to leave comment as we’d love to hear from you.

[@davidbain973]

This is the radio im currently using ,was neat to take a look inside

[@M0XFXUK]

Hi David thanks for stopping by the channel. It was a first for me too. These radios perform really well and I was impressed with all the features.

[@davidbain973]

@M0XFXUK ya, I really didn't realize it until I went through the manual ,ended up being a good little radio. 73 de kc0mxo

[@krahwinkel9503]

Nice repair. Interesting to see how modern transceivers make use of the old fashioned superhead technology.

[@M0XFXUK]

Thanks for the comment. Yes it's a cross between old an modern radio designs, these radios do work very well and are easy / fun to use. I was impressed with the overall performance.

[@ravichandransrinivasan5453]

Very good demonstration of faukt finding and repair

[@M0XFXUK]

Thank you I really appreciate the comment

[@christopheriles1469]

Thank you for another fine video John. Really enjoyed watching it. Look forward to the next one!

[@M0XFXUK]

Hi Chris always a pleasure to see you drop by the channel. Glad to hear that you enjoyed the video. Unfortunately at present I can only make one video a month due to work commitments.

[@christopheriles1469]

Yes, but they're high quality when they're done and worth waiting for.

[@houdielbow5770]

Hi John , I’d missed this instalment till now somehow .. great video as always 🤝

[@gerrytrouse4074]

Nice repair. Interesting

[@M0XFXUK]

Thank you for your comment

[@zaperfan]

Thanks for posting great informative video

[@toolmanchris]

Nice one John another interesting video 👍

[@ddsvfo]

Great job and great video! Thanks.

[@M0XFXUK]

Always a pleasure having you stop by the channel, I'm glad you enjoyed the video.

[@cqdx1677]

Where is the Tx power limiter in this radio. İf i wannto increase Tx power to 150 watts, what must i do??

[@m3hnl]

i have a ft 450 with a ldg yt 450 autotuner it works realty well thank you

[@CBRadioWayBack10-4]

wow, just goes to show when a radio has no output it's not always the output stage at fault like most suggest or think. i wonder if it was a faulty ic or caused by another fault, no antenna, high SWR or working out of band perhaps ?? great video though..would loved to have seen the hot air job..

[@M0XFXUK]

I couldn't find anything else wrong with it. I am not sure if these Quad Mod/Demod IC's are problematic. It's a strange fault but that being said these things sometimes happen. The radio looks brand new like it's not had any use. Could be just a bad IC that got through QA/QC and burn it from the factory.

[@golden-balls-radio]

1st class repair

[@M0XFXUK]

Thank you for the nice comment

[@philsnascar]

hi John i see you are familiar with a lot of these radios and do a good job on them ... I have a question or two you might have an idea of what i am up against if you don't mind... I hesitate to bother any one but i have a Kenwood TS820 s I have been working on and got it up and running but i get no Alc as far as i can tell the agc and alc circuits are there and to the meter amp etc ... any way on 20 meters i get no s meter readings yet on 40 and 80 if anything they are set a bit high it receives great and i am now able to get a plate current idle and adjust it after removing a mod on the power transformer i fixed the digital display finally i think any way its worked ok since I last worked on the boards and connectors. i removed another mod off the IF board and returned it to factory i didn't like the way it was wired in and the instruction sheet wasn't the best but it looked like they had it wired wrong basically it was dead other than powered up when i got it ... any way I am a retired tech with a VOM as i sold all my test equipment years ago now with 74 year old eyes it keeps my mind working plus i was off ham radio for years working as a tech but wanted to get a base radio and get on the air again ... I got a Kenwood ts 50 that was hooked up reverse polarity and i got it running but really want the ts 820 s for my station .. thanks for listening i know you are doing a great service and a awesome job here on you tube helping guys learn 73's WB7ASV Phil .... if you rather not discuss the radio here understand

[@M0XFXUK]

Hi Phil, Thank you for your message, it's difficult for me to to comment on your radio equipment unless I have it on the bench. Regarding the TS-820, I see that there are a number of issues. I wonder if if all the faults are related. I am making the assumption that the radio was working correctly and all these faults appeared at the same time? If this is the case the radio may be working correctly but not displaying the correct information, this can happen. It could be problem with the information getting back to the micro controllers. In the past I have found looking at the schematic and try to identify something i.e IC that all the problematic issues are connecting to, a multiplexer IC perhaps. When I get some free time I will take a look at the schematic and get back to you. I hope this is of some help best regards John M0XFX.

[@philip1380]

@@M0XFXUK Thank you very much for your interest and advice I do appreciate it I know this radio was in the hands of some one that should not have been it even the yellowing in the service manual it just makes me try to find out what else he did ... I have a feeling he tweaked with out knowing and i see a lot of evidence of him in it ... I really would like to see if he did something in the ALC circuit so i go on line hunting for those that's how I got my IP current working he changed resistor values on RF board he added a resistor to the bias control which I left so far as it does seem to be working now and also the windings on the transformer he moved the 220 v transformer circuit over to the 300 making two 300 v sources and i wondered why I was getting 300 in the where it should be 210 v any way i am going to recheck the vr 1 and 2 in s meter circuit again know ALC is going to that also and the vr2 is suppose to control sensitivity and it seems like its could be a issue I wonder if it could be playing a part in no ALC meter readings too

[@patrickdiddly1]

Please can you assist, I have bought a 450d and the screen is orange and black and I was told it was white and black, can this be modified??

[@M0XFXUK]

To be honest, I am not sure if it is an issue. Maybe someone has changed the display backlight to orange, or Yaesu may have bought out a model in this colour. Not sure?? Sorry I could not be of more help.