Hi all,
I’ve been messing a bit around with a CD5500 that I got for cheap. I love the DAC and sound, so I’d like to add it to my audio stack.
I’ve now added nice RCA plugs and I’m now also able to use my mobile phone as a remote control via an ESP32 web server and the datalink80 interface.
I’m now in the process of recapping.
One of the things I noticed that the ripple on C13 (4700uF) is significant with 1.4V. It’s not terrible, but it is something to investigate.
I then noticed that the rectifier diodes (D11-D14) before C13 are getting insanely hot. I think at least 80degC already after 1 or 2 minutes of playing. The soldering spots of those diodes also don’t look like they will survive many more playing hours.
A simple solution would be to replace those diodes with Schottky diodes, which should be a very big reduction of energy cooked off in the diodes, however, this energy will then be cooked off by the LDOs, which have a heat sink.
Still, i don’t feel comfortable with this. Calculating back from the ripple on C13, I estimate the current drawn here is somewhere in the direction of 1A, which seems quite normal for what is connected to it. 1A on those diodes (1N5401) seems quite modest and do not explain why those things are getting so hot. An explanation could be that the transformer has become very ‘soft’, and that bad inductances stress the diodes around the reverse point an exceptional lot.
So, a few questions:
- What are the experiences with recapping of C13 and the ripple voltage? Is my 1.4V anywhere in range?
- anyone also noticed the very hot diodes, and what did help?
- anyone replaced with Schottky, and what are the experiences?
- are bad transformers a thing?
