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Kenwood TW-4000A overheater? Aug 27th, 20:46 3 244 on 28/8/19
power for Kenwood TW-4000A Aug 22nd, 18:14 5 265 on 25/8/19

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Kenwood TW-4000A overheater? KN6CWJ on 28/8/19
Another success story. Thank you W1VT for pointing me in the right direction.
Kenwood TW-4000A overheater? KN6CWJ on 27/8/19
This is a continuation of my immersion in to ham radio and working with a very old Kenwood TW-4000a. With the assistance of member of the forum community I was able to power up the Kenwood and there were signs that it was working. Next with the assistance of others I built a 2-meter J-pole out of some copper left over from a bathroom remodel. Did not have any coax with the right connector so I disassemble an old CB radio antenna and connected it to the J pole. Much to my surprise when I fired it up and changing the antenna, I could receive transmissions from a repeater located about 40 miles away. I had setup the radio and antenna on our deck which turned out to be a bad idea. The temperature that afternoon around 95+ degree. Something must have fried. The Kenwood still had power but it no longer scanned and I could not manual change frequencies. I would get a repeating beep. I thought that if I disconnect everything and allow it to cool down it would reset itself. Unfortunately, it did not have any effect. I did a YouTube search that provide directions to disassemble the Kenwood and how to change the 3v battery. I have not put the Kenwood back together yet but I doubt that the battery could be the problem. I have been able to download the schematic. So, my question is if this is an overheating problem where would I begin to look. Using the schematic as a guide where should I begin my problem determination.
power for Kenwood TW-4000A KN6CWJ on 25/8/19
Got It. Thanks
power for Kenwood TW-4000A KN6CWJ on 23/8/19
Thanks for the explanation. As I mentioned this is all new to me. Taking what you said I connected the AC adapter (12v 2A) directly to the radio. With the multimeter it was 12 volts and .4 amps. But as you explain when I press the ptt the amp jumped up to 2.3 amp. So, one can now conclude it takes more current to send than receive. A day of enlightenment! This of course brings up the next question. How can you increase amps without increasing voltage? Does ohm law get in the way?
power for Kenwood TW-4000A KN6CWJ on 22/8/19
Hi. I preface this by stating I am a retired software engineer not an electrical engineer. I can figure stuff out but for the moment I am in baby step mode so bear with me. I just recently received my technician license and join the local ham radio club. One of the members saw an opportunity to get rid(unload) of some of his old stuff and presented me with a Kenwood tw-4000A. He said it would be a good way to immerse myself in the world of ham radio. My thought is to set the Kenwood up as a base type unit but make it portable as well. I have no manual or any of the cables so the first challenge to to figure out the power source. My first thought was to use a booster. The Kenwood requires 13.8 volts and 7.5 amp. I purchased a WHDTS 5A Buck Boost Converter LCD Display, DC-DC 10V-50V Step Up Power Supply Module Adjustable Boost Adapter CVCC Constant Coltage Constant Current Converter with Shell. I used an old AC to DC power plug input 100 240 VAC and an Output of 12 volts 2 amps. I connected the booster output to the radio setting the volts to 15.8. The booster showed 6.6 watts .4177 amps which is not even close to the 7.5-amp requirement. So dumb questions time. What is the implication of not achieving the Kenwood volt amp levels. What do I need to learn to get the output to 13.8 volts 7.5 amps?

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