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Dx2547 power supply issues


Transformer stays powered. I had a old radio shack 23B that used to do that. Like a door bell transformer. Seems like they always have a small hum.
A thought. Hope some one else chimes in
 
When the hum is there, can indicate several things.

Loose wind.
Poor rectification - Diode may be going leaky...
Filter caps bad...

Cherokee CBS1000 - I had, "hummed" all the time - replacing the caps did not help.

Found out later the issue was with the power transformer.

Cost too much to replace it - so bartered it off. (pre-2006 - so now there are switching power supplys that could possibly have replaced it...not back then)

The power supply in the base, is a Linear-type so it will always "draw power" and yes, if parts fail - depending on what can fail - magic smoke will erupt. The cap 10,000uF 35V, the Diode Bridge - there is also several Zeners and a disc cap or two - along with the power switch - that is on the output side of it.

Nomad helped me understand this better...
So If I get this wrong - its' on me because I didn't listen...:)
DX2517PowerSupply.jpg


Between the two there are very little differences in theory, only the Uniden uses the GROUND to remove the bias off the regulator feedback side - no bias, no regulation - dead...kinda' thing. In doing it this way, you still have a liability but the + line output is nearly at zero. This can help if you have a filter cap preparing to go out.

Now, in looking at the above, you can see there are very STRONG similarities to the AM regulator used in most of SSB radios today.

Just some thoughts...
 
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I may had mistaken the power supply im reffering to its the Ac to dc power supply that is making hum. model# Mean Well RS-100-12
 
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Well, then you may have to replace the wall-wart that it is. I'm sorry I thought you had already repaired this by installing a more dedicated supply - forgive the bewilderment look of "Deer In The Headlights"

Rudolph.jpg
Sigh...And this is happening soon enough...​

I was just giving you some ideas as to if you wanted to try installing a more dedicated supply - they did one using the one on the left for its' "Brother" the 2517 - while on the right is a Uniden style - both are linear.

(Didn't you say something to the effect of a dim Clarifier light? Thought you had fixed it.)

Now with the "wall-watt-wart" you have, be VERY careful with them because there may not be any fuses to hold back a bigger problem of overheating that can occur - that is one of their main symptoms, is a hum that can make even the wall vibrate - that means the internal winds are really loose or worse, and if not corrected - can fail in a short condition and start a fire.

They can also, as time progress before their failure - consume A LOT OF ELECTRICITY to generate that heat.
 
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I may have found the issue I measured 2 main filter caps they both read 125uf using my tester and the caps are rated for 150uf think they are making that hum. will keep you posted
 
What are you up against?

Later models...

DX2517LinearPS.jpg

Earlier Models...
DX2517LinearPSEarlymodels.jpg

And now your using a switching style...

DX2547PowersupplySwitching.jpg

Which one ? I'm thinking the bottom RS-100-12
 

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