I received a Yamaha MT8XII from Adrian James form the channel we happy few music for servicing, and somewhere in its journey from the south to the north ends of the British mainland the Vacuum Fluorescent Display stopped working.

I've had smaller displays die on me before, but usually there was something very obviously wrong with the glass exterior a bit broken off, a crack, etc. But this wasn't the case here. So I learned a bit about how these contraptions work, and other modes of failure.

The conclusion I've come to is that if the glass breaks, spoiling the vacuum, you're stuffed. If on the other hand the glass is in tact but the VFD just isn't lighting up, you might be able to recover it .

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TETRAKAN Fix & Use Tape Recorders

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CHAPTERS
0:00 Introduction
1:00 Anatomy of a VFD diagram & disclaimer
2:00 Glass case & acuum extraction port
2:40 Three internal layers of a VFD
3:28 How the VFD works
5:20 Pin layout
6:10 Establishing the health of VFD filaments
7:10 VFD counter on a Tascam 244
9:03 VFD display on a Tascam 424 Mk II
10:59 broken pins on the MT8xII's VFD display
13:04 soldering problems
15:40 Protecting a weak solder joint with 2 part glue