EEVblog

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!

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

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/