Repair of a Sony HCD-SBT20B Bluetooth Stereo. What it's like to nail the repair and then, well come-a-gutsa and have to go down the rabbit hole to fix the fix all whilst battling bad design info. How VFD displays work: https://www.youtube.com/watch?v=gZIRPJt69sM Forum: https://www.eevblog.com/forum/blog/eevblog-1603-sony-amplifier-repair/ 00:00 - Sony HCD-SBT20B Bluetooth Stereo with a water ingress problem 01:17 - Water isn't that bad actually, even mud. 02:49 - Comically long screwdriver time 04:09 - Vacuum Fluorescent display for all you VFD fanboys 05:10 - Annoying construction 06:14 - Logic level problem? Doesn't seem to be the PSU. 07:57 - Yuck! 09:58 - PCB Cleaning time 12:11 - Did the cleaning work? 13:28 - Hang on, I think I see something... 14:36 - More corrosion 15:21 - Back to measuring voltages on the VFD 17:15 - Handy use of Auto Hold 18:00 - VFD dispaly under the microscope 19:33 - Cathode measurement 20:13 - Anode connection tracing 22:10 - I wouldn't have designed it like this 23:08 - Sanity check 24:32 - What's in the can? 28:16 - Schematic time. Sony service manuals are something else 33:22 - Don't come-a-gutsa on dual diode pinouts 35:16 - Let's power it up on the bench 37:19 - There's something very strange about this... 40:04 - Oh FFS! 42:03 - Now it'll work... If you find my videos useful you may consider supporting the EEVblog on Patreon: http://www.patreon.com/eevblog Or with crypto: BTC: 33BsprBQNBtHuVzVwDmqWkpDjYnCouwASM ETH: 0x68114e40ff4dcdd384750500501e20acf3875f8c BCH: 35n9KBPw9T7M3NGzpS3t4nUYEf9HbRmkm4 USDC: 0x68114e40ff4dcdd384750500501e20acf3875f8c LTC: MJfK57ujxy55su4XicVGQc9wcEJf6mAoXF Web Site: http://www.eevblog.com Store: https://eevblog.store/ Other channels: EEVblog2: http://www.youtube.com/EEVblog2 EEVdiscover: https://www.youtube.com/eevdiscover T-Shirts: http://teespring.com/stores/eevblog #ElectronicsCreators #Repair #Sony ... https://www.youtube.com/watch?v=u6tuZ7plOa4

Dave takes a look at how to optimise the low burden voltage multimeter design from PART 2 to eliminate some parts. And explains the µCurrent shunt circuit design and how that applies to this new optimised design. It's basically a practical tutorial in circuit design optimisation. Then another design variation is presented using MOSFET switching that eliminates ones of the HRC fuses and the amplifier, and still lowers the burden voltage yet again! PART 1 is here: https://www.youtube.com/watch?v=jx0dryLmUEQ Forum: http://www.eevblog.com/forum/blog/eevblog-929-designing-a-better-multimeter/ EEVblog Main Web Site: http://www.eevblog.com The 2nd EEVblog Channel: http://www.youtube.com/EEVblog2 ... https://www.youtube.com/watch?v=xSEYPP5Xsi0