Re: Need Help setting the PA Bias Current for sBITX
|
Aaron,
Tom is correct. Once you fry your finals new ones installed must have the bias set to them. they will of course have slightly different characteristics due to manufacturing,etc.
When you set your Bias, before you apply power, make sure you have the bias pot set as low as possible . I dont own the SBITX but tom could tell you which way the pot needs to be turned.
after setting the bias as low as possible by turning the pot to the correct position, then after hooking up meter to measure appropriate measurements, then after double checking the finals and everything, apply power and SLOOOOOOOWWWWWLLY ADJUST THE BIAS CONTROL. AND I MEAN sloooowwwly. IF YOU CANT GET THE PROPER BIAS SETTINGS, THEN MAYBE SOMETHING ELSE IS BAD IN THE FINALS OR DRIVER CIRCUIT.EVERYONE HERE, can advise you on the correct settings and readings and the best points on the circuit to obtain them.
Just slow down, take ur time , copy and print out or write out the steps Tom and others give you and the SBITX will be on the air in time for field day if you want to test it out. plenty of hams will be listening for a contact .
frying the finals a big deal to alot of people but . plenty of replacements. and remember replacing the finals require resetting the biasing? since they probably wont be an exact perfect match.
I have popped many finals setting the bias to equipment i own. it happens to all who actually work on their own equipment one time or another.
welcome to the club,Aaron.
73 david ac9xh
On Sunday, June 16, 2024 at 09:46:59 PM EDT, Aaron K5ATG <aaron@...> wrote:
I have a v3. Ok let me understand this, I had to replace the finals and when I had to do that I have to adjust the PA Bias Current for the finals. When I adjust the PA Bias Current I blow the finals and now I have to replace them again. Once I replace them I have to adjust the PA Bias Current for them which causes them to blow.? Yeah this is a never ending rabbit hole deep into wacky land.?? -- '72
Aaron?
|
