I just performed this MOD on a HQ-100 I restored and the improvement is remarkable! Sideband has never sounded so good and tuning is a breeze! A big thanks to you for posting this.
Phenomenal that you've done this and thanks for including the 100a because I have one. These videos will be here forever as an amazing reference. I'll be the trying this mod once I get more experience with schematics and fully understanding circuits.
There is a video for converting a 110 or 110A to solid state but no separate video on the BFO. The BFO in the 110 should work as factory wired because it uses capacitor coupling already.
I have put the 47K resistor across the 6.8K R-12. No change. There as no oscillation point even with the knob turned all the way before, and there still isn't.
Do you have a 100 or 100A? Do you have an o'scope and a frequency counter? Does the BFO work or are you trying to get the Qmult to respond? Tell me more. Better yet send me an email with your details. I need the whole picture.
If you want to add a product detector to the HQ-100A, you might want to check out this link: k3jls.net/hammarlund.html. The circuit works very well on both CW and SSB, and the S Meter works just like it does on AM with the RF gain full up. I've used the same circuit on a HQ-145 and on an SX-99 - same great results. No need to ride the RF gain depending upon the signal strength. Currently looking for a nice HQ-100 to make a similar mod but with a separate home brew BFO. Joe - K3JLS
