[Premium-Rx] Racal RA-17L Overheating Problem

[Marco IK1ODO -2]

Joe,

Racal recommended to remove the top cover when installing the radio 
in the cabinet. I don't know what fails in your radio, but heath was 
a well known issue for the RA17 with cabinet.
 From page 9 of the manual: "A dust cover is provided with both 
models. This may be removed from cabinet-mounted receivers in 
conditions of high ambient temperature".
In practice, always :-)

73 - Marco IK1ODO


At 06:02 27-10-11, you wrote:
>Realizing that the RA-17L is not a "premium" receiver by today's 
>standards (but still a pretty good radio!), I wanted to poll the 
>group re a current problem with my RA-17L.
>
>It has the top and bottom covers and is housed in the original Racal 
>cabinet.  Works great until it cooks for a couple of hours and then 
>performance suddenly drops way down.  I notice that by the time this 
>occurs, the innards are very hot to the touch---including chassis 
>and power transformer.
>
>I am still in the process of isolating the problem.  So far, I have 
>replaced the tubes plus an electrolyic capacitor.
>
>I was just wondering if any of you have any experience with those 
>sets overheating?
>
>Of course, I could rig up a muffin fan, a la the Collins HF-2050 
>treatment and perhaps avaid the problem, but I would like to find 
>out what is doing it.
>
>I expect to eventually isolate the problem, likely to a 
>heat-sensitive capacitor.  I did the customary refrigerant spraying 
>on accessible parts on the bottom, but there are quite a few goodies 
>packed away in the RF and other modules on top of the chassis that I 
>have not yet subjected to that treatment.
>
>I am currently in the process of taking a few key voltage 
>measurements before and after failure occurs in hopes of finding a correlation.
>
>Any thoughts would be welcome.
>
>Joe
>W5WBR