Sony RDH-GTK1i/HCD-GTK1i boombox iPod dock volume barely audible

[WHaThEFLuX]

Hello All, I acquired a Sony home audio docking system from a friend who no longer wanted it. He explained to me that while he was using it with his ipod connected all of a sudden the volume became muted. Upon further inspection I discovered that music was playing, but the volume was so low it can barely be heard. The volume control does have an affect on the volume level, it goes from inaudible at any setting to barely audible at max.

Every other function concerning iPod control works perfectly, and any other input plays music at the correct level.

My first instinct was to pull the iPod board and check for anything suspicious, but I couldn't find one bad joint or broken pin.

The easiest thing to do would be for me to spend $60 on a replacement board, but I'm worried that it might not resolve the issue.

So badcaps vets to the rescue! Input? Thoughts? Suggestions?

I've included a picture of the iPod board along with the service manual for the system....tell me what you think, any advice would be greatly appreciated!

[stj]

Re: Sony RDH-GTK1i/HCD-GTK1i boombox iPod dock volume barely audible

does it work o..k. with the tuner or phono inputs?

[WHaThEFLuX]

Re: Sony RDH-GTK1i/HCD-GTK1i boombox iPod dock volume barely audible

Tuner and aux/phono work perfectly.....I've gone over the schematics with a fine tooth comb and I just can't seem to figure out what could be causing the volume loss. I'm almost certain it's the board but the usb port is also attached to the same board and it works fine as well.

[stj]

Re: Sony RDH-GTK1i/HCD-GTK1i boombox iPod dock volume barely audible

try injecting audio into pins 27/28 of the ipod connector.
it's using analog.

that will tell if it's the audio stuff, or the digital control of the ipod.

[WHaThEFLuX]

Re: Sony RDH-GTK1i/HCD-GTK1i boombox iPod dock volume barely audible

That's a great idea, I'll definitely try that.......any specific method of doing it?

[stj]

Re: Sony RDH-GTK1i/HCD-GTK1i boombox iPod dock volume barely audible

well i would try to solder a few thin wires to the back of the connector the ipod fits into - that will also test any interconnects.

[WHaThEFLuX]

Re: Sony RDH-GTK1i/HCD-GTK1i boombox iPod dock volume barely audible

so solder the L & R wires of a RCA to headphone jack cable to pins 27 and 28?

Or just plain old speaker wire?

[WHaThEFLuX]

Re: Sony RDH-GTK1i/HCD-GTK1i boombox iPod dock volume barely audible

Also, will I have to jump the ipod-detect pin so the unit thinks the ipod is connected?

[WHaThEFLuX]

Re: Sony RDH-GTK1i/HCD-GTK1i boombox iPod dock volume barely audible

Ok here's an update:

I connected an iPod to the dock on the board so the system would power up the speakers, and used an RCA to headphone jack cable connected to a playing iPod to inject audio into pins 27/28.

The result? The same barely audible music that was made when using the iPod dock normally.

I believe this would indicate that the board is bad and should be replaced, but I'm not 100% convinced. Is it possible that something is faulty on the pathway from the iPod dock connector to the amp?

[stj]

Re: Sony RDH-GTK1i/HCD-GTK1i boombox iPod dock volume barely audible

look at the schematic, there is a chip that switches between the inputs.

[WHaThEFLuX]

Re: Sony RDH-GTK1i/HCD-GTK1i boombox iPod dock volume barely audible

Are you suggesting that the input selector chip (IC201) is faulty? I also see a few line muting transistors, could they be coming into play here as well?

[stj]

Re: Sony RDH-GTK1i/HCD-GTK1i boombox iPod dock volume barely audible

i'll have to go back and look at the schems again.

[WHaThEFLuX]

Re: Sony RDH-GTK1i/HCD-GTK1i boombox iPod dock volume barely audible

Thanks, I really appreciate it! I know I can test the line mute transistors for resistance but I'm not too sure about the IC.

[WHaThEFLuX]

Re: Sony RDH-GTK1i/HCD-GTK1i boombox iPod dock volume barely audible

So it seems the line mute transistors are good, anyone know of a reliable way to test a SMD IC?

[stj]

Re: Sony RDH-GTK1i/HCD-GTK1i boombox iPod dock volume barely audible

link the input pins for the line and ipod on the selector chip,
then see if playing sound into the line while the ipod is selected reaches the amplifier.

[WHaThEFLuX]

Re: Sony RDH-GTK1i/HCD-GTK1i boombox iPod dock volume barely audible

link the input pins for the line and ipod on the selector chip

I know the ipod pins are 6 and 8 on the selector chip, not sure about the line pins?


By line do you mean aux? Like the jump the aux/ipod pins on the selector, then play sound into the aux lines with ipod selected?

[stj]

Re: Sony RDH-GTK1i/HCD-GTK1i boombox iPod dock volume barely audible

yes, exactly - so sound we already know works right though the system is injected into the ipod input of the selector.
if it still dose not output loud sound then i am 95% sure it's that chip.

[WHaThEFLuX]

Re: Sony RDH-GTK1i/HCD-GTK1i boombox iPod dock volume barely audible

After linking the aux and ipod pins on the input selector chip, I still get barely audible sound when ipod is selected with music being played through the aux ports.

I believe we've narrowed it down to IC201 so I'll order one and see if that does the trick!

[stj]

Re: Sony RDH-GTK1i/HCD-GTK1i boombox iPod dock volume barely audible

is it locatable?
my experience with sony stuff is they like to use unusual or rare part numbers!

[WHaThEFLuX]

Re: Sony RDH-GTK1i/HCD-GTK1i boombox iPod dock volume barely audible

If it exists, I can find it. I discovered on the sony site that they use a company called Encompass as a parts distributor(http://www.encompassparts.com), typed the part # into the search field and it popped right up, if it works it'd be a real nice $7 fix!