Posted on Sunday, 4th March 2012 by Auw Jimmy
It comes upon a time when my DACT Stepped Attenuator needs a clean-up. Well, if you see below picture, the connectors are getting rusty. I could hear significant noise when changing the volume. Although some external cleaning spray has been used, but it seems they only solve the problem temporarily. I do need a serious overhaul on this stuff.
Basically, it doesn’t take a genius to remove this stuff. They are all removable and repairable, although I’m not so sure if this overhaul could bring back this attenuator as good as the factory originated setting (screw pressure, precision, etc). But as I don’t have so much choice, then I think I should do this – at risk!
First, I just have to remove 2 screws and a plastic lock. Later, the spacers are easily removed then finally the PCB which contains the SMD resistors also removed.
Below is the comparison between the already cleaned-up board (right) with the rusty board (left). Night and day different, huh?
The SMD resistor on the back of the PCB. There are 23 pcs resistors on each PCB, configured in series to build an 100 KOhm stepped attenuator.
Below is the most important part of the goods. It’s the bridge connector which will connect the resistors to build the needed resistance (most left items). On the center is the spring which will push the bridge to stay in certain pressure level.
After the first gang is removed, then I continue to the second gang. Similar parts and process to be done.
Finally, all of the parts are removed and off course all of them will be cleaned up.
The process is done. All the cleaned parts assembled together again. Not quite sure if the pressure, position, etc are matched with the factory original setting. But at least the connectors are cleaned up and no more producing noise which could be irritating.