These radios suffer from so many issues. From leaking caps to ageing components. Great job on getting it back up and running Peter. I enjoyed watching you work through it.
@@TRXLab Sir I could use your advice. I am currently about to purchase a " New in box Kenwood TS 50". That's right " New in box". An elderly gentleman had purchased it, but never got the chance to use it before he passed away. It sat in a closet for many years. It is in an open box but the unit is completely mint. There is absolutely no signs of use . Closeup on the coax output threads and the finish shows zero signs of ever having a coax on it. The mic is flawless and the power connector shows zero signs of ever having been connected. My question is this.....how likely do you believe the caps are toast from just age , ( no use)...or anything else for that matter. I know you don't have a crystal ball....but your best guess is appreciated.
I remember back in the 90's me and a friend were experimenting on a Kenwood TS-440. While watching the wattmeter, he cranked the ALC to zero and started turning up the carrier. At about 330 watts it blew up.
Really nice video Peter. Many problems in one video. That's a nice keithly meter. It's fast !. The graph is great for a visual view of what's happening. Thanks for another nice video. I learned a lot. 73
Thank you Peter for another great video showing us how to logically and methodically start with the symptom and slowly work back through the circuit and diagram to find and fix the issues with the radio. If only I had half of your knowledge, but I would probably be a danger to the radio LOL Take care and looking forward to your next video.
Ha ha funny Peter, when you say that the zener diode falls on your floor - and disappear. I experience just the same, any component that falls on the floor is gone. I am sure I have a black hole under my desk, which consumes anything that comes close to it. Thank you for another interresting repair video. Take care. 73 Asle
You see why Kenwood TS-50S, the 1st of the full power small HF rigs has disappeared from the used markets in the States They have not aged well, and are just not worth fixing. This is too bad it is a nice little radio when it is working.
From the start, I figured it was ALC and as soon as I saw the carbon film pot, I was suspecting it. I would have thought that the buck converter would be OK, but that zener is being worked hard to supply -6.2VDC. That poor drive transistor didnt stand a chance at 16dBm 😢. Great job, on this one. Bet that PA was getting toasty at 230 watts out. Your test gear is unbelievably good. I used to use an HP8640B as a signal generator back in the 80's, wish I had one today.
Wow. That was a ton of fun. Thank you so much for this project. It was a wonderful way to spend my Sunday morning. The Keithley DMM is awesome. I am envious of such excellent tools. Much appreciated.....
I used a Motorola SyntorX on 2 meters. Its nominal power output was 100 W, but I adjusted things and added a 3 level output switch of 5W, 40W, and 175W. It was very useful that way. The 5W was what I normally ran it on and it saved battery power and with its huge heatsink could run in Xmit mode forever. The 40W matched other rigs running simplex in car convoys and such, and the high power was a 'last resort' that I never used except for short tests, since I was unsure how long the output transistors would last at that power level, as I could not get specs on the transistors from Motorola. They are a very secretive bunch, something I never liked about them.
Excellent troubleshooting video Peter! I always wanted one of these radios (TS-50) when I was younger, but after seeing what a pain it is to access some of the parts, not so much anymore! LOL! All that said, troubleshooting and repair have always been a bit of a love/hate thing for me. I love troubleshooting but repairs can, on some radios, be a headache! Great Video in any event! Thank You!
Thank you so much for posting this video! Mine had a similar issue where I was getting 150W on all output settings. If it weren't for this video I wouldn't have checked the buck converter for the -6V supply. Mine ended up being the 1mH inductor on the input of the buck converter and not the Zener but this video pointed me in the right direction!! Thanks so much, 73!
WOW! That was a struggle, Peter... Not only do you have the expertise to diagnose such repairs - more importantly, you also have the persistance needed to follow the problem through to the end! Negative voltage DC converters always seem to be a source of BIG problems in old receivers and transceivers.
Another fun trip down mystery lane ; ) At what point is repair no longer cost effective considering labor cost these days? Must be a labor of love at some point. As an Amateur Radio enthusiast its rewarding for me to watch a radio "resurrected" Thank You Again : )
I only operate in CW mode, so I do not need linearity of final amplifier. so I changed ALC setting, many radio can do well above 200 watts , specially in lower HF band. 100 watts is for SSB which require good linearity. AG6JU
Good video. I do not know the history of the radio. It is unfortunate that a lot of radios across my bench have been 'tampered with' . My first guess would be that the pots for the ALC have turned more times than a doorknob from others trying to get more power. Took out the transistor. Not sure on the negative vibrator. That tacked on cap looks like something the factory would do. I too keep some vintage transistors around as best I can to save older radios. Please keep video's going, we are watching out here, thank you.
Based completely on nothing but what you pulled out of a rear orifice. There was zero evidence that anyone was twiddling pots in this radio the transistor was still working when he received and tested the rig.
@@johncundiss9098 No, I just randomly reply to comments that my ouiji board tells me to. Of course I read your comment. "My first guess would be that the pots for the ALC have turned more times than a doorknob from others trying to get more power" What other radio would you have been talking about here if not "that particular radio"? Do pots turn themselves? How else would they be turned so much unless the radio was "tampered with". So yes you said this particular radio was tampered with. Perhaps you need to read your own posts more carefully before clicking that reply button.
@@stargazer7644 Yeap, my first guess. Right before that I said alot of radios across my bench. I am not the one who has let my alligator mouth overload their paper asshole on a video 3 months old. Next I got the love from the creator cause he agrees with my comment. P.S. When I do get a radio that has been tampered with improperly my labor rate doubles.
Another nice video, Peter! I have a IC-2200H with similar problem. When I press the PTT, the output power drops from 65 to 50W in 2 sec. and 10W in more 2 sec. When I change to 5W, the power increase to 10W in same time above. So, in HIGH the power drops, in LOW until MID, the power increases... Do you think is this the same ALC problem reported by you? Kind regards!
Hello, I am not a technical radio operator, but I do get some pleasure, and some knowledge from watching your ,(TRX Lab) Videos. I am the owner of a Kenwood TS 450S radio. It was purchased as a silent key sale. It had a fault on RX, low audio .I checked, and found the fault was a blown Elec/ capacitor, replaced by a friend, now working fine. But then found that the TX was intermittent. Switch on the radio, no TX, then sometimes switch on and 100 watts output? Can you advise a starting point to trace fault? Have you done a repair video oh this model with TX fault? Kind regards and best wishes, James, G0EUN
Sir I could use your advice. I am currently about to purchase a " New in box Kenwood TS 50". That's right " New in box". An elderly gentleman had purchased it, but never got the chance to use it before he passed away. It sat in a closet for many years. It is in an open box but the unit is completely mint. There is absolutely no signs of use . Closeup on the coax output threads and the finish shows zero signs of ever having a coax on it. The mic is flawless and the power connector shows zero signs of ever having been connected. My question is this.....how likely do you believe the caps are toast from just age , ( no use)...or anything else for that matter. I know you don't have a crystal ball....but your best guess is appreciated.
Capacitor are mostly jeopardized if an electronic device is not used over a long time, so yes there is a good chance that the caps in the radio are dead.
So, I'm working on two TS-50s and they both appear to have the same problem. HP E6380A analyzer: generator into PA, Analyzer reads power. 1.83Mhz: -23dbm=1.0w, -5dbm=6.85w. More drive=no more gain just higher current draw. 3.5Mhz is better but also no full power. 29Mhz: -21dbm=1.17w, -12=11.7, -7=50.4, -4=97.8watts. I can drive it harder and the watts increase easily over 100w. This would indicate good finals but what could it be that is frequency sensitive? As I am driving the PA directly and looking at the so239 output I can't seem to understand where to problem is. Filter board, but on both radios? And then how to test that! Sheer stubbornness keeps me going. Any thoughts?
Peter, is it correct to say that the problem with these components is attributed to age and not to maybe transmitting into an antenna not tuned properly? And if the conclusion is with the fact that the components are at their “end of life”, that the rest of the circuits are reaching their end of life dates as well? Or is the issue with the ALC components being under more operational stress? Thank you.
I really like your videos but there are too many ads that prevent me from staying engaged. Literally every 30 to 30 seconds I get an ad and it it makes it hard to follow what your doing. I have to tap out, sorry…
