You know, I don't see you chasing signal paths around the radio; instead, I see you taking voltage measurements. I guess it's easier to do voltage measurements rather than chasing a signal through the radio. Your methods are so straight forward and you always arrive at the bad component. In this day and age of throw away electronics, it does me good to see a technician such as yourself, chasing the fault down to a component or two. This is simply unheard in our day. Cheers & 73 from W Rusty Lane K9POW in eastern Tennessee
Big Thumbs up Peter it is a joy to watch an engineer at fault finding Peter it shows when you get shorted diodes what it can do bring the negative voltage to zero you were lucky to be able to get the new diodes in as there was very little room but designers never think maybe sometimes you need to replace components and you can do with a little extra space as time goes on some components can change in size peter you would think they don't want you to change components but to throw things away and not repair being of electrical field I like to repair if I can fix it but well done Peter :)
Hi Peter, Great video, very logical, your approach to repair, one step at a time and eliminate each step before continuing to the next. Again great video...
Another nice work Peter, congrats.We're always learning, the space for the diodes was very tight, but it work out ok, the final result is what matters.
Thanks for another great repair Peter. Good job at packing those over sized diodes in that circuit. Guess if you would had to replace all 4 you may could laid them on their side with small jumper wire. 73 my friend.
Nice job Peter! It's always a real mystery why components fail as you might expect that the circuity involved would not subject those diodes to extremes. 73 - Dino KL0S
+MikesRadioRepair Hi Mike, thanks for stepping in! Yes the new Diodes have a higher reverse Voltage by even lower reverse leakage current therefore those new diodes are ideal ! All the best 73
+Robert Calk Jr. Thank you Robert. Well it is still possible to get some of the original but they are far to expensive and the new ones have a higher ratings.. 73
+Donald D'Egidio LOL no idea Donald but contest operation is very rough so those radios are always candidates to come back onto the bench. Thanks for watching 73
Good work Peter, thank you. now I have the same problem, two diodes short-circuit to ground. i found other schottky diodes but they work at frequencies up to 10 mhz. not working 14mhz and high. What kind of diodes you used, what is the part number? thanks
I wonder if you could have put those new fat diodes on their edges to make them fit in better. Maybe using small #30 jumper wires to the pads would have worked? Depends on if there is enough height space there??
+Herbert Susmann HI Herbert, yes that is possible most likely even without jumper wire. But as the other both diodes tested good I decided to do this way. Thanks for watching. 73
Any idea what could have blown those Schottky diodes? Seems a bit strange that they shorted as they were on the secondary side of the RF sensing toroidal transformer.
+Herbert Susmann Well to be honest no idea. But you have seen that they have to handle to short the positive half way to ground and over the years with this high dissipation they simply might have worn out... 73