jamo sub 260 plate components number removed

[ajith]

Hi,
Recently, my Jamo Sub 260 died and refused to turn on. I opened and inspected the amplifier; no burn marks, no suspicious components, and the fuse was not blown. I tested all the transistors and components and all seems to be fine, even the smd ones. However when i checked the voltages, I do not seem to be getting any current into each of the transformers. So as for now, i am suspecting it may be a problem with the power supply region of the amplifier. On the underside of the pcb are 2 smd chips, controlling the driver transistors (2 irf740s) of the main transformer. However, scratch marks are present on the ic packages and I am unable to identify what model number are those. My guess is that the problem lies within these chips(marked U1 and U2 on the pcb) that caused the failure of my sub. Does anyone here have any info of this chips or any relevant info to help me fix this sub?
Thanks!

 

[arjen]

Hi,

Unfortunately you did not have a reaction. I wonder if you managed to repair your subwoofer and if so how. I think I have the same sort of problem.

Thanks for the reply.

 

[AnalogEL]

Hello all,

Not sure if you have fixed your subwoofers already; I was looking around online and think that both of your problems might be related to "That awful yellow glue on circuit boards...":

https://www.electronicspoint.com/threads/that-awful-yellow-glue-on-circuit-boards.61364/

I can't imagine being a self-respecting design engineer and using it.

Anyway, good luck, tell us if you get them fixed!

 

[deepak_kakkad]

Hi, U2 is S2153D PWM IC, which controls the mosfets IRF740 for on and off.

U1 I am not aware of and will be happy if someone knows and posts the ic number of U1.

Hope this will help you to some extent.

 

[Hofnar1]

Can someone tell what component is BL1 it´s right next to big white resitor. Mine is shortcutted and burned black