21-04-2015, 08:33 AM
Occasionally, Youtube throws up a useful link and this one was no exception.
After several fruitless attempts to get a minidisc player to work with a home computer, any home computer for that matter and angrily throwing the lot into a box vowing never to touch the technology again, I had gone off in a bit of a huff and worked on other projected that required my attention. It was a case of the data being recorded correctly but the playback was spotty and the computer just didn't like it.
So, a few months back, following a Youtube channel recommendation, I came across the Joulespercoulomb channel. This chap does repairs on computers for a living, usually of the 30+ years old variety and his pages are interesting to say the least. On a recent +2 repair, joules knocked up a signal condition board out of an LM358 op amp chip. As you can appreciate my interest was piqued so out came the bits and pieces and from his designs a board was knocked up to fit a +2 I had kicking around on the repair queue. It's nothing fancy, the LM358 is configured as a Schmitt trigger to sharpen up the signal going in to something the computer liked better. So, I dug out the minidisc player and during tests found that the board worked 100% as advertised. Data could be reliably loaded from a MD player and sharpen up the data from the good old fashioned tape variants as well. very pleased.
I've stuck a screen grab of the circuit diag below and veroboard layout, the only odd items in the circuit are a pair of shottky diodes, everything else is bog standard resistors and caps.
After several fruitless attempts to get a minidisc player to work with a home computer, any home computer for that matter and angrily throwing the lot into a box vowing never to touch the technology again, I had gone off in a bit of a huff and worked on other projected that required my attention. It was a case of the data being recorded correctly but the playback was spotty and the computer just didn't like it.
So, a few months back, following a Youtube channel recommendation, I came across the Joulespercoulomb channel. This chap does repairs on computers for a living, usually of the 30+ years old variety and his pages are interesting to say the least. On a recent +2 repair, joules knocked up a signal condition board out of an LM358 op amp chip. As you can appreciate my interest was piqued so out came the bits and pieces and from his designs a board was knocked up to fit a +2 I had kicking around on the repair queue. It's nothing fancy, the LM358 is configured as a Schmitt trigger to sharpen up the signal going in to something the computer liked better. So, I dug out the minidisc player and during tests found that the board worked 100% as advertised. Data could be reliably loaded from a MD player and sharpen up the data from the good old fashioned tape variants as well. very pleased.
I've stuck a screen grab of the circuit diag below and veroboard layout, the only odd items in the circuit are a pair of shottky diodes, everything else is bog standard resistors and caps.
