· Caution: Not all 9505 schematics and units are the same. My 9505 component designators are different from the schematic on the W1VD site. I did find a very hard to read schematic that does match my unit.
· John (W1TAG / WD2XES) and myself exchanged a number of emails the other night and determined that there are three different models of the 9500/9505 amplifier. The C15 cap designator talked about at the W1VD page is different in each. Considerer yourself warned. Mine is apparently the old 9500 model but has a front panel that says 9505.
· The bias pots in my 9505 were painted over so that they could not be adjusted. I measured them in circuit and they appeared to be bad. Purchased new ones. Upon removing the old ones, they were indeed bad. I installed the new ones and then they checked correctly in circuit. The 200 ohm pots are Mouser part number 531-PT10V-200, Mfg part number PT10LV10-201A2020 made by Piher.
· If you ae using a K3s in transverter mode, be advised thee are no lowpass filters out of the K3s. Every harmonic is well represented. I needed to put in a bandpass filter after the K3 to calm down the Hafler. QRP Labs makes a cheap and simple lowpass filter system for 2200 and 630.
· Repaired mine and it was relatively painless. Bad FET. Bias did not need adjusted. FET are readily available from eBay and can even be bought in pairs.