XDR Heat Problems: Give it as much ventilation as possible!
The photo below shows the long-term effect on the XDR's main board from running the tuner continuously without fans. The board is literally heat-scorched around voltage regulators (most of them are on the bottom solder side). It even smells burned.
This is what a pristine board should look like:
Typical symptoms of XDR heat damage include:
- Tuner gets stuck on flashing WAIT message
- No signal strength or audio from any station you try to tune
- Persistent hum in the audio
- Choppy "helicopter noise" audio when tuned to an HD station
Sometimes the power supply isn't delivering adequate voltage or current to the main board because the main aluminum electrolytic filter capacitors in the power supply have severely degraded. The electrolytic capacitors on the main board and inside the tuner/DSP module can also degrade to the point where the tuner doesn't sound good or isn't working at all.
The HD Module is very susceptible to heat-induced failure. If you get choppy audio when tuned to an HD station, your HD module has probably failed. The only source for a replacement module is removing a working one from another Sony HD tuner or radio that used the same module.
I'm also seeing increasing numbers of XDRs with long-term heat damage affecting the plastic case. The most common point of failure is at the mounting posts for the transformer. That transformer gets VERY hot. Eventually the plastic screw mounts for the xfmr become brittle and crack. They literally fall apart. Here's an example with both posts broken off.
The XDR Absolutely Needs At Least One Cooling Fan. Two fans are better.
Bottom Line: the XDR's internal components get very hot. There's no getting around the need for a cooling fan to keep everything as cool as possible, especially those pesky modules that are no longer in production and very expensive to replace.