[R-390] Z503 Failures

[ROSS HOCHSTRASSER]

Hi all, As it turns out I did successfully  repair one a few years ago and it did work. This one was out of a Collins R-390 (S/N1501) and it was open circuit. I figured I had nothing to lose, so I took a 1,000 ohm resistor and my variable bench DC supply and cranked it up to 500 volts. I drew an arc from the resistor lead to the  coil lead(after disconnecting the capacitor) and  it arc welded the break inside the coil. It is definitely possible that I lost a turn or maybe a few turns  in the welding process, but it tuned up and worked nicely until I discovered that the 390A also uses the same coil and stole one out of a parts set and replaced it. I still have the one I "fixed" and it checks OK with an ohmmeter, but I didn't want to have a failure, so I left the replacement in the radio.  It may be worth the try!! 73 Ross W1EKG
> On 03/16/2023 1:24 PM Jacques Fortin <jacques.f at videotron.ca> wrote:
> 
>  
> About those Z503 failures: does anyone tried to repair a defective one already ??
> Please share your experience.
> 
> 73, Jacques, VE2JFE in Montreal
> 
> ______________________________________________________________
> R-390 mailing list
> Home: http://mailman.qth.net/mailman/listinfo/r-390
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:R-390 at mailman.qth.net
> 
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html