Summary of Wavetek 907 Repair, YIG Oscillator Teardown
The article details the troubleshooting of a Wavetek 907 microwave frequency generator where the display showed out-of-range errors and the frequency range was limited to 6.9–7.9 GHz instead of the full 11 GHz. The author suspected a faulty PTC heater in the YIG-Gunn oscillator but decided to perform a teardown for inspection. The process involved removing mounting screws, unfastening a directional coupler from the RF assembly, separating the cylinder halves, and detaching an SMA connector that held the covers together.
Parts used in the Wavetek 907 Repair:
- Wavetek 907 microwave frequency generator
- YIG-Gunn oscillator
- PTC heater
- Directional coupler
- SMA connector
As I mentioned in my previous posting, there was an issue with my Wavetek 907 microwave frequency generator. While everything was fine during my initial testing, the frequency display is now stuck with an out-of-range display and the adjustable frequency range is limited to between around 6.9 Ghz to 7.9 Ghz (instead of all the way up to 11 Ghz). My initial suspicion was that the PTC heater inside the YIG–Gunn oscillator was malfunctioning. But as it turned out, it was something else.
Since initially my gut feeling told me that the YIG oscillator might be at fault, I thought I would at least try taking it apart to see if it was something trivial to fix. And even if it is beyond economical repair, it would at least be a pretty interesting teardown of the YIG oscillator itself.
Dissembling the YIG oscillator was a bit more involved. I first had to take off the mounting screws and unfasten the directional coupler (see teardown images in my previous post) in order to get it out of the RF assembly. Then I had to remove the mounting screws holding the two halves of the cylinder together. The SMA connector also needed to be removed as it was used to hold the top and bottom covers together.
For more detail: Wavetek 907 Repair, YIG Oscillator Teardown
- What symptom indicates a potential issue with the Wavetek 907?
The frequency display is stuck with an out-of-range display and the adjustable range is limited. - How does the malfunctioning PTC heater affect the device?
It was initially suspected as the cause, though the actual fault turned out to be something else. - Can the YIG oscillator be disassembled for inspection?
Yes, the author attempted to take it apart to check for trivial fixes or for an interesting teardown. - What components must be removed to access the YIG oscillator?
You must remove mounting screws and unfasten the directional coupler from the RF assembly. - How are the two halves of the YIG oscillator cylinder separated?
You need to remove the mounting screws holding the two halves together. - Why is the SMA connector removed during this repair?
The SMA connector is used to hold the top and bottom covers together. - Does the device still function after the initial testing phase?
Everything was fine during initial testing before the frequency display issues appeared. - Is the repair considered economical if the oscillator is at fault?
The text implies it might be beyond economical repair, making the teardown a learning experience.
