DX7 power supply fire?

Hi! Glad to have found this forum!

I am a DX7 owner from when it was brand new in the mid-80s, and recently I saw a post elsewhere that said there was a common problem which some DX7’s have that causes the synth somehow not to turn off with the power switch, or turn on/off randomly, and in some extreme cases, causing fire.

I can’t find any detail on this, and am wondering if anyone else has heard of this? It was presented as a capacitor failure in the post, but I can’t imagine how a cap failure would cause the power switch not to be functional.

Does anyone know any detail or history on this? I’d love to replace whatever might fail before it does, and save myself from a potential fire!!

Thanks in advance!

Yes, This is a failure of the RIFA capacitor by the power switch. The capacitor is there by government regulation to prevent the synth from causing noise on the city power line. These capacitor fail at their end of life and are suppose to not short, but they almost always fail in a dead short, or explode in a ball of flames. If you plug in your synth, and even though the power switch is off, the synth turns on, is confirmation the RIFA cap has shorted. Good news is these are industrial parts used in many many commercial products. The original part was rated for 250V, which had a high failure rate on countries with 220-240V power. Digikey sells an improved part (rated 300VAC) P/N 399-12410-ND which works in all models.

Thank you SO MUCH for the detailed description… It’s funny you mention specifically the RIFA branded cap… I just watched a youtube video about how old Apple 2 computers had RIFA caps that were notorious for failure!

I’ll order a couple of these caps right away and get it replaced! I haven’t seen the problem yet, but I’m not going to wait for a failure!!