Pretty hard to offer advice with this limited info .. but a few q's may shed some light.
The slings and pops are Williams special solenoids. Do they fire in the solenoid test?
Do they fire if you take a direct feed from the solenoid bridge to the coil with a bit of wire?
When you say the 15000 uF cap is ok, how did you determine this?
What bits of the previous advise did you follow or what work did you do or bits did you replace?
