Hey, all. First--I have been having a great time with my QDX. I've made numerous FT8 and JS8 contacts. I've even worked with other FSK modes with this little transmitter. I built mine for 9VDC input and I am seeing 5W on 80, 40, and 30 meters. I sometimes see between 5.3 and 5.6 on 40M. I am getting 3.8W on 20 meters.
So, Right when I was working an FT8 QSO, I heard what sounded like a crack sound from inside the QDX enclosure. Then, the smell. I knew then something went terribly wrong. I found the cracked BS170 as soon as I pulled the board out of the enclosure. I'm in the process of buying new BS170s. I know it is a TO-92 style, but I am seeing other variants of the transistor: D26Z, D74Z, etc. I have three questions:
1) Is there a specific BS170 I should get or will any of them work provided it's a TO-92?
2) Is there anything else I should do to prevent another BS170 fail?
3) Has anyone found an alternative to the BS170 that has less potential for failure?
Thanks,
Wayne KB4DSF
