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oled display question

 

a cap fried 470pf on my atu-100,first i noticed was the burnt smell and no display,i took it apart,on testing the 7805 was outputting 12v,,would the overvoltage have killed the oled?,or have they there own onboard regulator?,i assume the pic is toast?.
 

Hi Paul,
Most of the OLED display modules do have an on-board 3V3 LDO regulator, but they have a maximum voltage rating of around 6V.
I suspect the regulator and OLED display will have been damaged. The PIC will also be dead if it had 12V applied to it for any length of time.
73, Dave
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well i have another pcb,ive replaced 3/4 of the caps with 500v silver mica,to my supprise my original oled works,glad over that as its a replacement bigger 1.2" unit i fitted to the blownup atu,the old pcb with the blown cap seems dead tho,i have not tried to read the pic yet,guess the chain of events most likley was a high missmatch caused the cap to blow then rf killed the 7805 that shot 12v into the pic and scrambled its contents or killed it.
 

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OR¡­ something caused the 7805 to fail, blew the PIC which caused all the relays to turn off or on causing a high VSWR, blowing the cap.

Or... something else. :)

Clark Martin
KK6ISP

On Dec 4, 2023, at 8:32 PM, Paul M3VUV <nanovnauser@...> wrote:

well i have another pcb,ive replaced 3/4 of the caps with 500v silver mica,to my supprise my original oled works,glad over that as its a replacement bigger 1.2" unit i fitted to the blownup atu,the old pcb with the blown cap seems dead tho,i have not tried to read the pic yet,guess the chain of events most likley was a high missmatch caused the cap to blow then rf killed the 7805 that shot 12v into the pic and scrambled its contents or killed it.

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