LG XA146

[pdf64]

I'm looking for a schematic for an LG XA146. It's a CD/radio/docking station combo with separate speakers.
This belongs to a friend and it's taken a bash that's ripped out the pcb mounted speaker output sockets and a few other output stage parts.
Thanks!

[Jazz P Bass]

Contact LG did we?

[pdf64]

Yes but I don't hold out much hope of getting anything useful out of them.

[Jazz P Bass]

I had a Klipsch unit come in similar to that one.

All of the ribbon cables where glued down.

It was a nightmare.

I bagged it & told the guy 'no way;.

[oc disorder]

Just had a quick look... one here at a Russian site but you have to do a test and register..???

LG XA146 - ????? ? Service Manual - Audio - LG

LG XA146

Service Manual MICRO Hi-Fi SYSTEM LG XA146 (XA146, XAS146F)
After the Registration and passing the Test , you can freely download the file. (Размер файла:12.69Mb)

Good Luck on your mission !

[MarkusBass]

I passed the test and downloaded the file for you. If you send me your e-mail address (as a PM), I will send it to you. It's 12.6MB size.

Mark

[pdf64]

Service manual received, many thanks.
Unfortunately it doesn't have any spec on a missing inductor; each (balanced) speaker output has one of these.
The other 3 are marked 220, which from the size 11mm dia x 15mm high, I guess indicates they're probably 220uH.
Their resistance is very low, no different from shorting the Fluke probes together.
The power amp is rated at 2 x 70Wrms, but as the SMPS PSU and power amp IC heatshink are somewhat insubstantial, I suspect that rating is for a momentary, rather than continuous, signal.
The speakers look to be 8 ohm
I was hoping for a current spec, but again from the size, then compared to what's available from parts houses, I guess about 2A.
I think I'll try this RFS1317-224KE COILCRAFT, Inductor, RFS1317 Series, 220 µH, 2.05 A, 1.7 A, 0.239 ohm, ± 10% | Farnell element14 but will need to build up the order value to get free shipping.

I guess that the series inductor (together with a cap to 0V) is to filter out the modulation signal?
For test purposes, until I replace the missing inductor, would it cause a problem to operate the amp with a link across the inductor's place?
Here's the power amp schematic, it's L5 that's missing

Here's a product page http://www.lg.com/au/home-audio/lg-X...ro-hifi-system

[MarkusBass]

I would wait for the delivery of the inductor. It (together with the capacitor) forms a low-pass filter to remove high frequency from the signal sent to the speaker. The speaker may, or may not withstand the signal with removed inductor. Your colleague has to wait anyway for the amp to be fixed. He should be happy that someone is going to fix it . This is quite advanced amp and the damage is quite serious.

Mark

[pdf64]

Doh, from the power amp IC info sheet http://www.st.com/content/ccc/resour...CD00042511.pdf the output indictors will almost certainly be 22uH.
Just as with caps etc, the 220 must be a 2 number value then a multiplier.
Thanks to @nickb for PMing and suggesting I check such a useful info source!

[MarkusBass]

Nick is right (as always ). I've just checked an inductor marked "470" with my EXTECH meter and the inductance is 51uH. So the last digit is a multiplier. But this leads to a question whether you can measure the inductors that you have. If you don't have a meter that can do it, you can measure it with a signal generator (or at least compare the old inductor with the new one when it arrives).

Mark

[pdf64]

Close out report
Replacement 22uH inductor obtained and fitted (it was also marked 220).
It was a little smaller than the other 3, so it may saturate earlier, or it may just use a better spec material.
Whatever, it should cope with the claimed full power and (being a free repair for a penniless acquaintance) it had the considerable advantage of being a free sample with free delivery (big thanks for the heads up nick!).
All that was left of the damaged inductor were its legs, so no chance of checking it.
RG's tip over on diyguitaramps to use a toothpick to clear the old solder out of pcb holes came in handy, and I managed to avoid my trick of lifting any pads even on this cheap board.
The system all went back together ok (phew), now works fine and sounds surprisingly good.
Thanks to all for your invaluable help with this

[mcgaiver]

Could you share with me the schematics please? I don't find the private message button.