Golborne Vintage Radio

Full Version: BBC B Dual floppy drive overhaul
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This particular unit was one of Siralan's earlier incarnations, Viglen badged in this case.  Labelled duff the unit needed a good check over and a look at why the 40/80tpi switch on one drive was not operational.

The PSU for these units is built into the rear of the drive, and contains a nice toroid transformer along with a selection of capacitors and the usual 78xx regulators.  Of note, three fuses inside, one for mains, and two for each output voltage rail, +5 and +12 volts.  Getting the circuit board out is a grade A pig, you need to pull out the power switch before releasing the four PCB screws and the nut and bolts for the regulator.  All of the capacitors were tested on an ESR meter and found to be perfectly good in quality, a pleasant surprise for a thirty plus year old unit.  Testing, all voltages correct, the PSU was reassembled.

The two 5.25 drives were in good condition.  Failure of the 40/80tpi option was traced to a loose yellow wire that had been poorly soldered years before and some cleaning of the solder pad on the control board enabled a good fix.  

Testing tomorrow, and an opportunity to dig the BBC out of storage.   Goodluck