First , we have to check how extensive is the damage.
The 200v 1A fuse is blown, the diode bridges are in short circuit . According to the schematics :
After the bridges there are 2 linear voltage regulator , an LM340 -12 and an LM340-5 , both converting whatever the power should be ( someone is saying 16VAC and 9VAC ) out of the bridges , down to 12 and 5 volts.
My multimeter says that there are no shorts between ground and 12/5v so , ideally , if I feed the regulators with 19v dc for a small amount of time I should be able at least to check if the rest of the drive works:
And indeed does it! It's alive!
my expression when the disk started to read the floppy
The first thing to do was to find a power supply, I wanted a Mean Well D-50A but the real thing was way too expensive , I ended up finding a chinese knock off of the same model for £13 , reasonable for me.
Once I received it I just put a dummy load on it and tested it with the multimeter, I was impressed to see how was keeping up with the voltage under stress.
The old transformer :
Once the PSU was sorted out, I did turn my attention to the drive, the large PCB carries the voltage regualtion and the logic on the same board.
Both regulators and diode bridges have to go :
that's better, now we have to trace down the voltages , because the transformer output AC and we have the diode bridge pads we can basically use the traces as we want , I ended making jumpers on CR1 and CR3 and reuse the cable for the connector P1 , P1 in my configuration is cabled as :
1 - 12V
2 - GND
3 - 5V
4 - GND
After that I just soldered two jumpers between where the input and output of the regulators should be :
The board is now ready, let's take care of the placement of the power supply :
It's a very tight fit, I had to use the screw terminal in a very uncommon way :
I made sure to cover all the nearest area with kapton tape.
I used cable ties to keep the psu in place, I didn't wanted to drill holes and glue and double side tape are out of question , I completly ignored the fuse, in UK we have one in the plug, one in the socket and the PSU have short and overload protection, sound safe enoght for me :)
Once everything was in place, I screw it back togheter and try it on my setup :
Works beautifully! :D
No over heat , or heat at all and the weight went from 5kg to 3.4kg !
I'm really pleased about the outcome of this , I can store the driver under the screen without worring about ventilation , the next step is to swap the original ROM with JiffyDos !