Sony RDH-GTK33iP no display, no panel buttons work except for power

[WHaThEFLuX]

Since my last boombox repair was successful I figured I'd try another! I have a Sony home audio mini system that I got off ebay for $1. The power button was sunken in so that it wasn't making contact, after fiddling with it I got it to turn on to what seemed to be the AM/FM function. I can hear static coming from the speakers, but the volume adjustment does nothing to change it and there's nothing on the display. I assume it's the AM/FM function because when I play with the antenna pins in the back the static sound gets louder and changes.

I haven't attempted any repair yet since this unit has a much more extensive tear down than the last one, so I figured I'd post up on here and see if anyone has a place for me to start!

As a side note, all LED functions seems to work and there's also power to the Ipod and USB connections.

I've included the service manual , if anyone would be willing to take a look it'd be greatly appreciated!

[WHaThEFLuX]

Re: Sony RDH-GTK33iP no display, no panel buttons work except for power

Well I found the problem:

[Longbow]

Re: Sony RDH-GTK33iP no display, no panel buttons work except for power

Nice to have the complete manual, but its a bit early in the process. Everything depends upon following a method. Now's the time to make good habits. Start with what you know, which is quite a lot actually. The power button was pushed in and nothing on the front panel is working. That suggests to me that someone bashed the front of the unit and may have cracked the pc board that holds the power button and other front panel devices. Start there, looking for damage to the front pcb or parts on the pcb. If the power button now works and the unit wakes up, your main control micro is working - good sign. Another good sign is hiss in the speakers that indicates that the audio output stage is probably working. Grab your tools and tear it down. You will get your $1.00 worth!

Oops, looks like you already did what I thought. Super glue will repair the broken board, then you have some fun with #30 wire-wrap jumpers to fix the broken traces. Don't try to repair them using solder bridges.

[WHaThEFLuX]

Re: Sony RDH-GTK33iP no display, no panel buttons work except for power

So after discovering that it's impossible to find a replacement board, I decided to try my first ever cracked board repair.

It was by far the most intricate soldering work I've ever done, and after many hours of staring through a jeweler's loupe until my eyes were strained, I ended up with this.

This is currently my finest soldering achievement and perhaps the sloppiest job in rework history, but I'll take function over form any day!

Even after the last trace was patched, I was certain I had wasted an entire evening attempting something I thought couldn't be done with my skill set/equipment (or lack thereof), but when this thing lit up and was fully functional I was like a little kid on Christmas morning!


I have absolutely no expectations of longevity out of this repair, but the experience gained was well worth the $1 and sore eyes!

[WHaThEFLuX]

Re: Sony RDH-GTK33iP no display, no panel buttons work except for power

Longbow, I probably should've waited for someone to respond on here before attempting the repair!

I wasn't even aware that wire jumpers existed(shows my experience level), that probably would've saved me a ton of frustration and eye strain.

If anyone wants a good laugh, the trace bridges are single strands of speaker wire that I sanded and tinned one by one!

[rhomanski]

Re: Sony RDH-GTK33iP no display, no panel buttons work except for power

I keep a spool of solid wire for old stereos. A lot of time you'll find the boards turning dark, they tried to run too much current through the copper traces. I parallel the runs with wire. Pioneer in the late 70's would run two lines of solder down the sides of some runs. That solved the problem. The early ones though, they'll turn black and brittle if you don't do something.

[Longbow]

Re: Sony RDH-GTK33iP no display, no panel buttons work except for power

Thanks for your photos. That's how its done - good work. Many techs will try to solder bridge each connection to avoid using jumpers, but it is never reliable. Also keep in mind that you do not have to jumper the cracked trace right at the point of breakage. It may be much easier to leave the break alone and connect the jumpers further back from the area of the crack, rather than fighting with the glue. My reference to wire wrap - #30 wire wrap is a convenient size for this type of work because it is insulated, flexible and the circuit does not require high current traces.