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Old 21st Oct 2019, 4:04 pm   #68
Uncle Bulgaria
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Join Date: May 2016
Location: Cornwall, UK.
Posts: 2,314
Default Re: Uher CR240 Troubleshooting Best Practice

Back home and trying to put the smoke back in. A labour of love even more as now some of the tracks on the PCB have tried to escape the flames by leaving the board. I've got some Zener diodes on order and have cannibalised a spare board for some transistors.

I think the trouble was that the loudspeaker pressed against a couple of the new capacitors I had put on the main board. As the board was already cracked, this could bring the bottom of the board into contact with the chassis, shorting it. I'm going to insulate the base after replacing the broken components! Fishpaper on the way from RS.

Question:

As some of the new electrolytics are taller than the tantalums they replaced, what is the consensus on ceramic capacitors instead, for the smaller size?

RS has some 100nF, and right up to 470uF MLCC through-hole capacitors! I understand that for some applications they can have the wrong characteristics, but the size is what matters in some positions on these boards, as I discovered to my cost.
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