Logitech Z906 Power Supply

[storexxm]

Hello dear Badcaps users.
I recently bought a broken Sub. After opening i saw those burnt ?resistors?
One small SMD on the back got lost...
Do you guys thinks its possible to repair the Sub?
Unfortunately i dont have any clue what parts i have to order :/
Hope someone can help me out.
Greetings, Alex

[stj]

the board is o.k. so if you can find out what the parts where you could fix it.
that and maybe find out why it happened.
if this is common then some "upgrading" will be wise.

[storexxm]

Does anyone have a schematic or something like that... the parts where totally burnt... so cant read what they have been. Dont think it's a common problem, because I couldn't find any thread about this issue.
Maybe somebody can have a look at a complete board?

[budm]

https://www.youtube.com/watch?v=VSfqKv3Arw4

You have to search more for the burnt SMD resistor which can be difficult.

[storexxm]

The smd resistors have a bigger value than 0.33 ohm... more than 1M Ohm.. do I need to change them all? And is there a chance that It will work after changing after all those resistors... no idea what caused the shortcut...

[stj]

R030 isnt it?
30milliohms

so 5 in parallel = 6milliohms or 0.006ohms!
maybe thats the problem, not able to handle the current.
maybe fitting a physically bigger current-shunt inplace of those will help

[Gabriel]

Good pictures of the burnt resistor here - https://imgur.com/a/xPmqG
R22 is the same as R21.

[stj]

ok.
so .33ohms x5
0.066ohms

[storexxm]

Those two guys also seem to be dead... i couldn't find the exactly same value to order (googled it) does anybody know what I should order?

[stj]

https://www.onsemi.com/products/disc...fets/fqpf9n90c

[storexxm]

Thank you stj. I will try those

[stj]

those are what you have in the foto

[storexxm]

waiting for parts from abroad... will tell u more when reassambeld power supply

[stj]

Originally Posted by storexxm

waiting for parts from abroad..

tell me about it,
this SCAMDEMIC has trashed the suppy chain in europe so badly that even a fuse has to come from china if i dont already have one!!

dont miss-understand, i can buy parts in europe, but the suppliers have imposed a handling fee and/or a large minimum order rule.

[storexxm]

know exactly what u mean...
half of the parts were not possible to buy here (austria).. or u pay 1000x more for shipping costs for some SMD resistors...

[ant3202]

anyway see this I also shake my head on this SMPS ....
almost the same fate as the altec lansing mx6021
those conductive glue... and when transistors shorts... it bring down those component around.

Originally Posted by stj

tell me about it,
this SCAMDEMIC has trashed the suppy chain in europe so badly that even a fuse has to come from china if i dont already have one!!

dont miss-understand, i can buy parts in europe, but the suppliers have imposed a handling fee and/or a large minimum order rule.

you are right, risk of missing items also.

[storexxm]

resoldered everything back... plugged in and the area on the picture looked burnt... both 2 fuses died also... cant see what exactly burnt... any ideas what happend here... and what i can do to repair this thing....
please

[storexxm]

could the part R51 (SL12 10006 Inrush Current Limiters) the problem... for a shortcut?

[storexxm]

https://www.elektroda.pl/rtvforum/topic3195173.html

I found this post... I did not change the D22...
ISL6721 is a little bit complicated to swap... so do u think it's worth just to replace d22?

[1Turk]

what is z906 power suply volatage output pin ?