Obviously you must be referring to me! :)
What you're describing was a common problem a few years ago on a different brand of radio. They used a microprocessor built by North American Philips, (NAP), the same company that builds the really terrible Magnavox tvs. That microprocessor developed a similar symptom, but there were a number of variations as to what initiated those symptoms. On most of them, the volume would cut out when you moved the volume control, (from any setting to either direction). Some acted up when moving any of the two or three tone controls. Another common symptom was the display and radio went dead, then there was a thumping sound once per second in each speaker, and the lights in the tone controls pulsed on and off in time with that thumping.
The fix for those radios was to replace the microprocessor IC, then burn in the correct software for the specific radio model. I have the high-tech soldering equipment to replace the part, but they'll never sell me the very expensive equipment to install the software. Lacking that equipment, those radios were not repairable by any independent repair shop. Fortunately, there was an almost identical radio built by Mitsubishi, with one additional button, that was a direct replacement. It looked the same, mounted the same, used the same plugs, could run the same remote CD changer, but it weighed twice as much. Those models were very popular on eBay. Used car dealers snapped them all up to replace defective radios in their cars. The original radios had a 100 percent failure rate.
The second problem is starting with GM in 1994 and Ford in 1997, they will no longer allow us to buy their radio service manuals. Most other manufacturers followed suit after that to keep the repair business locked up for themselves. For that reason, you're tied to the dealer for this problem. A lot of people used to toss those GM and Ford radios and install high-quality aftermarket radios. To combat that, GM started to build their Body Computers into their radios in some 2002 truck models, so they couldn't be removed. They are really desperate to hold onto that repair business, and they make a lot of money on it from their customers.
One thing that was not included in the description is what happens when you turn the volume back down? If the sound comes back, there is another real common problem that IS repairable. This applies to radios with volume controls that have lots of tiny clicks per revolution, and you can spin the knob continuously in either direction, (as opposed to the older common type of control that can only be rotated within a 270 degree range). That continuously-variable control uses two on / off switches that are staggered slightly. Based on the order those switches turn on and off, the microprocessor figures out which way you're turning the knob. Problem is those switch contacts get dirty causing the microprocessor to see confusing signals. The two symptoms are, the volume doesn't change at all when you turn the control, or the volume goes the wrong way. To add to the misery, those controls are usually riveted together making it nearly impossible for standard chemical cleaners to work their way in to to their job before it evaporates. I have a cleaner that I call "nuclear waste", because it cost over $55.00 for a gallon, and is no longer available since the late '80s. I charge $1.00 for one drop of it at old car shows, and it has never failed yet to solve a volume control problem. Other shops can only replace those sealed controls, but those will develop the same problem in a few years. You might consider this if you can ever get the volume to increase properly. That would be proof the rest of the radio is okay.
As a point of interest, as though I haven't provided enough of them already, I recently used one drop of that chemical on the scroll wheel for my $2.00 Chinese-built wireless mouse. It has the same type of sealed switch assembly and it started acting just like those dirty volume controls. Works fine now.
Friday, December 2nd, 2016 AT 4:45 PM
