Ok, that's somewhat encouraging. I assume you've double-checked the polarity of the electrolytics that you replaced?
You didn't say whether you know the drill for operating these beasts, so I'll run through the basics below. I've only used them in VLF, zero discrimination mode, but I've successfully hunted both coin and treasure targets at parks, old homesites and beaches (in dry and wet sand and shallow water), as well as nuggets in the Victorian goldfields.
Firstly, switch on and leave the Sensitivity at the barely On position - DO NOT turn it further clockwise, as this will reduce sensitivity (counter-intuitive I know, but this is a Garrett)!
Flip the handle toggle switch to the left, to ensure VLF mode is engaged. Forget about TR mode - always use VLF.
Turn the TR/Discrimination knob fully anti-clockwise (to zero) and leave it there permanently.
The Tuning section controls the threshold. Flip the switch upwards to Automatic and leave it there permanently. Use the Metal - Null pot to set a low but audible threshold. The so-called Automatic Detection System (ADS), is just an auto-returning threshold, but makes all the difference in mineralised ground, as the only control that counts is the 10-turn Ground Balance.
Set the Ground Balance by bouncing the coil up and down below knee height and turning the multi-turn pot until you find a point where the threshhold volume is as stable as possible while the coil is moving both up and down. This is very easy to do once you've done it a few times, but it will need constant attention while prospecting, as ground balance is wholly manual - there is NO ground-tracking function.
From memory, the Deepseeker operates at 6.6kHz, which is an extremely low frequency for maximum signal penetration, but with the penalty of being very noisy in mineralised ground. The smaller 15kHz Groundhog was much friendlier to use (quieter) and more sensitive to small gold, but supposedly gave away some depth to the mighty Deepseeker.
I hope this helps - good luck.
