Hello and welcome. I will get straight to the heart of what I can see from the photo but first:
All of our Guides including how to get voltages and troubleshoot are located in one convenient place.
That said looking at your photo I see a heavier gauge of wire than we typically like to use which would be a 24 gauge but even so your gauge will fit if done carefully. (Proof is in the diameter of the 1N4001 Diode lead used). The reason I bring this up is because many of the connecting wires are dangerously close to shorting out on each other. Some of the pads almost appear to be lifted off the board (watch heat). You may wish to investigate those closely and take care when re-flowing or you may damage the pads. I cannot see what the back side of the board looks like, solder joints on the back or any off-board wiring for me to make any further observations that could be helpful.
Additionally many of the solder joints I can see have a dull look which would indicate a cold solder joint. Cold solder joints provide intermittent connections at best. All solder joints should be shiny so I would suggest a re-flow and try to push the wire carefully through the pads (watch the heat) till the plastic casing is flush with the board and trim any protruding leads or wire. Again be very careful not to burn the board pads. Use a fine conical iron tip like in the video in the link above. Then re-flow all other solder joints so they are clean and shiny. Please see the soldering video in the tutorial link provided above.
Also you need to verify all resistors by color band and capacitors by code as well as double checking all orientations. This is the mandatory method for troubleshooting basically any build. The reason being in our 9+ years of helping people troubleshoot 80% of the fixes were found to be due to an incorrect value being used. The link above also contains a chart with resistor color bands (since they can’t be measured in circuit) and capacitor codes. You may also choose to use an online resistor calculator if that is easier. (Google) In this case I would first spend a good amount of time going over the entire board very carefully and re-flow any cold solder joints as well as carefully fixing the wire dressing without lifting any pads. This can only be a good thing for future proofing any solder issues even if it were not the main problem.
Once you have done that and if you do not get satisfactory results we are going to need more photos showing all wiring including the DPDT On-Off-On switch, connections and back side of the board as well. We will also need voltages of all transistors (explained in the crash course guide) in the link above before we can begin to help since this is a complicated build. Please post back a report of all tests, new photos and voltages. Finally tell us what JFETs you are using and exactly where you got them.