As a retired Failure Analysis engineer, I really liked seeing the inner windings of the inductor. I've analyzed many malfunctioning components over the years, including inductors, but this one was particularly interesting since I'm also a Ham. Thanks Peter! 73 de KZ9L
Glad I waited to the end , I was going to say , I like to take things apart to see failures - heatshrink off , and you did . For it's a learning opportunity - how things fail & sometime why they fail . ;) Thanks again
Hi Peter, good to see you back making videos, I am not sure that the current rating is the problem, more likely the reactance is not high enough. If you consider the RF voltage present at 1.5kW and the reactive impedance of those inductors at 1.8MHz it looks worrying... I may be wrong....
I was under the impression that MFJ made quality products, but other hams think different. I saw another video of yours where you took apart the bias tee and found wrong value inductors. I can understand that a person can have a bad day and grab the wrong part for insertion into a product. This makes the second MFJ bias tee to go wrong. I think I would have remembered the problem from a previous video. I don't think I'd ever buy a MFJ Bias Tee. So then 2ea. 47 microHenry would total nearly the 100 microHenrys that you need. I see on the little board that two can be soldered in series. W Rusty Lane K9POW in eastern Tennessee
Maybe it might have been a nearby lighting strike that caused the problem? Wonder if he had any lighting protection on the coax? Alway enjoy your videos and your method of troubleshooting. 73 wd4dda
You can visually see the discoloration of the heatshrink on those inductors right around the middle where the windings are, it is clear they have been overheated.
I have MFJ automatic tuner and several of the diodes on the relays have been knocked off the PCB. It could only have happened at the factory. Says a lot about they quality control.
Hi TRX man or anyone who can answer my question. Out of all the models of the Yaesu FT-1000MP which model is the best one ? Which one will prob work perfect and not have faults if I buy a used second hand one ? Thanks
No, it has to do with the quality factor of the inductor (or "Q"). The L meter pulses the coil and then counts the number of "rings" of the decaying waveform. A high Q inductor will ring for a long time (larger number of rings or oscillations) compared to a low Q inductor. Shorted turns in an inductor will kill the Q of the inductor and will show a low number of rings or oscillations after an energizing pulse.
danke, hatte schon "Entzugserscheinungen ". . . . . . hatte dieses Problem schon, was durch eine direkte Stromversorgung des MFJ behoben werden konnte. BIAS Tee bleibt für mich eine Notlösung. 73s
Very educational videos. I could mail you my Alinco DJ-V27T, 220 MHz HT, receiver is deaf. TX is OK. I bought it on ebay and discovered it could not receive, only noise. Tim W8RNG
I burnt out the choke in my T also by letting the thing see a low resistance somehow? only had one choke in the T, so I rewound the choke with the same size wire and back in service.
I was thinking the same thing...coil forms looked OK, but did he have any enameled coated wire of the same gauge? Probably easier to just replace the part.
insert a manual tuner betweeb auto tuner and dummy load -- and see if the auto tuner will compensate for the L or C you introduce. IMHO the MFJ is crap.
