https://stream.echo6.co/videos/watch/5f2d9a81-b03e-4d3d-a241-19a55d23f4ad Repair of a JBL Partybox 310 speaker. Follow along as Dave goes down the repair rabbit hole. Try and guess the exact fault before Dave does, it's a doozy! Part 2: https://www.youtube.com/watch?v=n-mFgfLasM8 Service manual: https://www.scribd.com/document/811153867/esquema-JBL-Partybox-310-Service-Manual-v1-4 HP 1740A oscilloscope repair: Part 1: https://www.youtube.com/watch?v=Cmz8bzUsj7E Part 2: https://www.youtube.com/watch?v=7ocancoZ02Q Forum: https://www.eevblog.com/forum/blog/eevblog-1672-jbl-repair-youll-never-guess-the-fault/ 00:00 - JBL Partybox 310 Speaker fault symptoms and initial failure speculation 02:57 - Teardown 06:23 - Is it a firmware lockup issue? 07:17 - Checking the power switch 09:13 - Main PCB's 10:52 - Hello IT, have you tried turning it off and on again 11:46 - PCB microscope inspection 13:39 - Bench testing and, thou shalt test voltages 16:31 - Looking at the keypad PCB again 17:41 - Replicate the fault using an external PSU 22:55 - Schematic, we have Schematic! 24:14 - The power flow block diagram 28:44 - The penny drops 29:45 - Design TIP 32:04 - Without the schematic I'd be chasing a red herring down a rabbit hole 33:10 - Manual Bypass time to get it working! 34:50 - I called it at the start, but assumed incorrectly 36:33 - OK, let's trace WHERE this fault actually is 37:41 - No, it's can't be, surely not... 39:52 - But WHAT caused it? 42:05 - The repair 44:20 - Assembly back together and testing Web Site: http://www.eevblog.com Hardware Store: https://eevblog.store/ Merch Store: https://eevblog.dashery.com/ 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 Other channels: EEVblog2: http://www.youtube.com/EEVblog2 EEVdiscover: https://www.youtube.com/eevdiscover #ElectronicsCreators #Repair #JBL Wed, 15 Apr 2026 09:27:22 GMT https://validator.w3.org/feed/docs/rss2.html PeerTube - https://stream.echo6.co https://stream.echo6.co/client/assets/images/icons/icon-512x512.png https://stream.echo6.co/videos/watch/5f2d9a81-b03e-4d3d-a241-19a55d23f4ad All rights reserved, unless otherwise specified in the terms specified at https://stream.echo6.co/about and potential licenses granted by each content's rightholder.