[Milsurplus] BC-652 Video

[Tom]

   Always enjoy your videos, thanks!! 

                                      W6TOM

On 2024-07-03 12:53, Ray Fantini via Milsurplus wrote:

> Dynamotors and capacitors, have done a lot with homebrewing solid state inverters. Can do efficiencies and interference issues with ease. But this dynamotor presented itself at the right time, for the right place and on that radio the dyna fits right into the chassis. From the beginning the plan was to use this radio in the field so an AC supply was out of the question.
> Procedures, Step one is to strip out all the weird stuff so the AC power supply had to go. Step two was to return as much of the existing wiring back to the original circuit as possible. That did not take that long after removing the AC supply and the S meter circuit that was installed. Step three is to start doing power on test with HV applied and using current limiting as not to burn too much up. Its step three where you start seeing bad capacitors. You keep searching where current is going and what is and is not working. For some reason not all are bad, along with some having good capacity and high leakage or no capacity and no leakage. Think just about every capacitor that was a screen bypass and plate decoupling was high leakage with a couple being shorted, but some of the oil filed "bath tub" capacitors and other capacitors in the AVC and osculator systems were all solid. There was a big multi part filter capacitor in a rectangular can on the dyna deck that was the p!
 rim
> ary B+ filter that leaked almost as much current as the radio uses and that was replaced with three 10 uf 450-volt electrolytics.
> At least that how I do capacitors, way too many to just shotgun all of them and if they do work why not keep them in the circuit? These radios get run for hours on the bench so generally if they are going to fail you will see it right away.
> Completely different radio but same thing, on the Harris RF-350K transceivers you will always have at least a hand full of Tantalum bypass capacitors that short and burn up, but after the first couple hours of operation the ones that were going to fail will fail and the rest settle down and work. Don't know what causes this but suspect that if you don't apply power to those things every now and then that's when they go bad when you finally apply power. 
> Certain others who know better will tell you that you should change all the capacitors being they are all the same age or something like that or they only proper way to do it is with all fresh parts or whatever, me I just roll with trying to limit damage by current limiting and look for the current drains and try to fix them one at a time.
> As far as doing the videos goes, I do have a small advantage in that years ago I use to do a lot of that work for the government, Engineering and Education is where I spent the last thirty years but those old skill still work, and it's fun to produce and get those videos out there. Appreciate hearing that people like seeing them. 
> Have a great forth everyone.
> 
> Ray F/KA3EKH
> 
> -----Original Message-----
> From: mstangelo at comcast.net <mstangelo at comcast.net> 
> Sent: Wednesday, July 3, 2024 2:34 PM
> To: Ray Fantini <RAFANTINI at salisbury.edu>; MMRCG at groups.io; milsurplus at mailman.qth.net; mrca at mailman.qth.net
> Subject: Re: [MRCA] BC-652 Video
> 
> CAUTION: This email originated from outside of Salisbury University. Please exercise caution when clicking links or opening attachments from external sources.
> 
> Ray,
> 
> Enjoyed your video. Keep them coming.
> 
> I noticed you only changed some of the capacitors. What criteria did you se for capacitor replacement? Are the original rectangular capacitors mica?
> 
> Enjoyed the sound of the dynamotor. The last time I ran a dynamotor rig was the Wireless #19 set I got from my cousin. It kept blowing silicon rectifiers in my homebrew power supply upon startup so I ran it from the battery in my father's car.
> 
> 73 Mike N2MS
> 
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