x23 multiplier pcb assembly   - second batch.....
 
x23 pcb
x23 pcb top


HSMS-8202 back to back schottky diode (SOT-23 package)
D70
Inductor link
L70
Pre-tuned pipecap (with 6BA x 1/2" brass screw and brass nut)  2 off

Cavity to cavity coax link (50mm Quickform 86)

output coax lead assy (70mm Quickform 86 with one end terminated in an sma single hole bulkhead socket

Input probe wire (5mm length of RG-405 inner - see text)   Note: Item, if supplied, to be trimmed to length once fitted



Build notes

Assembly of this pcb is a little agricultural, nontheless it is very important to maintain the dimensions detailed below. Also, it is advisable to follow the build order below – if you must ‘do it your own way’, at least leave the cavity soldering until all the probes have been fitted (so that you check/readjust the probe heights).

The board is layed out for two smd capacitors, C70, 71, but these are not actually fitted.

Start by fitting the input probe. This is a short length of semi-rigid coax inner, and is supplied cut to length. It fits through a plated-through hole (the plating-through providing the outer conductor as it passes through the board).  The ptfe sleeve is an interference fit, but if for some reason it has been pushed out of the hole, beware that it may be harder to fit with the inner probe wire fitted, so in this case, remove this and insert the ptfe first – then push the probe wire back through the sleeve.

Once the probe is fitted, ensure that its ptfe shoulder is flush with the non-cavity side of the board, and then solder the shotkky diode pair (D70) into place, soldering the common lead to the probe first, before soldering the two ground pins

        input probe

Fit the sma bulkhead socket to the 70mm length of output coax, and prepare the other end so that, say 5mm, of inner is exposed. Likewise expose 5mm of inner at each end of the cavity-to-cavity coax lead, and bend into a 'U' shape with 10mm spacing between centres. Push the coax cables through the board holes as below, and ensure that the coax outer extends 1mm through the board. Solder the coax outers to rhe board. Ensure that the 'U' shaped coax ends are vertical to the board when fitting - this will enable the outer of the coax to push easily through the pcb hole without snagging, which tends to thicken it and cause it not to fit. Finally, cut back the 5mm exposed inner core to 1mm, as per the rest of the pic above. Where supplied, the coax's have already been trimmed to length, both in overall length and exposed probe length.
  
                       
        
coax fitment
input probe



              pipecap dimentions

Fitting the cavities onto the top side of the board

The two cavities have been pre-tinned on their bottom face, and the pcb solder resist pattern provides a good guidance for their accurate placement. They are also pre-resonated, so should already be on or very close to frequency.

A good hefty and hot bit is required to solder each cavity. For those using a Weller soldering station, the PT-E9 tip is ideal.



Cable cutting details
cable cutting



 
Alignment

Alignment is carried out at the unit assembly stage.