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Update on this. After closer look with the scope probing around, it appears that I have proper drive signal, Bias voltage, and switching (RX/TX).

The problem appears to be that if you replace the RD16HHF1 with a IRF520, you have to retune the output coils. I did not want to mess with that, will just order a handful of RD16HHF1's and when they get here, try replacing it, if a minor retune is necessary will do that. I think I'll add some sort of heatsink to the back of the radio, using a longer screw, some thermal compound, and a sil-pad insulator (or Mica insulator), since the RD16HHF1 transistors seem to have a reputation for being a little on the fragile side, the extra heat dissipation should take care of most of that issue.

Would have been nice if they would have designed this radio with a little better receiver, and dual RD16HHF1 output transistors for longevity sake. Still cannot believe after all this time, there is not a schematic available for this rig... The only reason I even want to repair it, is because it's in pristine condition, everything works fine, and I kinda like it's layout and functions.

<blockquote data-quote="443" data-source="post: 773955" data-attributes="member: 15034">Update on this.&nbsp;&nbsp; After closer look with the scope probing around, it appears that I have proper drive signal, Bias voltage, and switching (RX/TX).&nbsp; The problem appears to be that if you replace the RD16HHF1 with a IRF520, you have to retune the output coils.&nbsp; I did not want to mess with that, will just order a handful of RD16HHF1&#039;s and when they get here, try replacing it, if a minor retune is necessary will do that.&nbsp; I think I&#039;ll add some sort of heatsink to the back of the radio, using a longer screw, some thermal compound, and a sil-pad insulator (or Mica insulator), since the RD16HHF1 transistors seem to have a reputation for being a little on the fragile side, the extra heat dissipation should take care of most of that issue. Would have been nice if they would have designed this radio with a little better receiver, and dual RD16HHF1 output transistors for longevity sake. Still cannot believe after all this time, there is not a schematic available for this rig...&nbsp; The only reason I even want to repair it, is because it&#039;s in pristine condition, everything works fine, and I kinda like it&#039;s layout and functions.</blockquote>

[QUOTE="443, post: 773955, member: 15034"] Update on this. After closer look with the scope probing around, it appears that I have proper drive signal, Bias voltage, and switching (RX/TX). The problem appears to be that if you replace the RD16HHF1 with a IRF520, you have to retune the output coils. I did not want to mess with that, will just order a handful of RD16HHF1's and when they get here, try replacing it, if a minor retune is necessary will do that. I think I'll add some sort of heatsink to the back of the radio, using a longer screw, some thermal compound, and a sil-pad insulator (or Mica insulator), since the RD16HHF1 transistors seem to have a reputation for being a little on the fragile side, the extra heat dissipation should take care of most of that issue. Would have been nice if they would have designed this radio with a little better receiver, and dual RD16HHF1 output transistors for longevity sake. Still cannot believe after all this time, there is not a schematic available for this rig... The only reason I even want to repair it, is because it's in pristine condition, everything works fine, and I kinda like it's layout and functions. [/QUOTE]

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