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[Ziploc]

Hey guys, a good one for you experts or even novice. What are some reasons you amplifier transistors are shorting out ?

 

[Shockwave]

Because, there are literally no radios being manufactured for this band, that use good transistors designed for linear RF amplification. That includes most low power external amplifiers and even the high power ones using HG transistors, are nothing like the Toshiba's from years ago. Hams would never accept that lack of quality and is why you will NEVER find any HF rig that uses TO-220 case finals or HG transistors. These parts simply cannot be sold, to any market that knows better.

PS: Correction. I do understand Ameritron may be using the HG transistor in the ALS-500. It also explains why that amp now has horrible reviews, when it didn't with the Toshiba's.

 

[Shockwave]

To take this one step farther, "10 meter" solid state amplifier advancements, came to a grinding halt when the Toshiba's became extinct. Everything sold since then, has been a huge step backwards because this band has been extremely resistant to learning new MOSFET technology, beyond stuffing a power supply FET in place of a bipolar part no longer available. To make this transition effectively, requires the complete circuit, to be redesigned.

 

[AudioShockwav]

PS: Correction. I do understand Ameritron may be using the HG transistor in the ALS-500. It also explains why that amp now has horrible reviews, when it didn't with the Toshiba's.

Ameritron building solid state failures by the handful.
Tom has been posting pictures of heat sinks that still have raw milling marks on them, dirt and dingleberrys under the transistors, improperly mounted ....
The quality control from mfj is showing.


73
Jeff

 

[Shockwave]

Ameritron building solid state failures by the handful.
Tom has been posting pictures of heat sinks that still have raw milling marks on them, dirt and dingleberrys under the transistors, improperly mounted ....
The quality control from mfj is showing.


73
Jeff

Jeff, when I saw the inside of the MOSFET amp video he posted, I couldn't believe the amount of contamination in the most critical areas. With just a little effort, working on the ground in a dirt driveway, at night by flashlight, you could get less dirt under the output transistors. The "dingleberry" content, exceeds that of the heatsink compound.