I pulled out the wimpy 2078 along with r55, r56. C61 did not appear to have ever been installed in this radio. I built a en1230 from through hole components and placed it with the positive side towards the front of the radio in r56's holes. Replaced original final with 13n10 mosfet. I powered up the radio with the covers off (speaker disconnected-ext speaker plugged in) and was getting a 10w carrier with about a 45w peak. Sounded great on my scanner set to channel 21.
I hooked the speaker back up and put the covers on. Powered up the radio, tested receive which sounded good. The first time I keyed the Mic I got about 6w fading to zero, then came the smoke. Disconnected everything, pulled covers off and the finals heat sink was pretty warm, along with both power transformers that were extremely hot.
What did I cook and why?
I hooked the speaker back up and put the covers on. Powered up the radio, tested receive which sounded good. The first time I keyed the Mic I got about 6w fading to zero, then came the smoke. Disconnected everything, pulled covers off and the finals heat sink was pretty warm, along with both power transformers that were extremely hot.
What did I cook and why?