NHT SUB2 amp repair

Hello
I'm looking for advice on one of my repair projects. I'm struggling a bit and have tried to get this running for some time now.
The amp board in my SUB 2 is a 500w Recoton Home Audio Sub Woofer Amp Rev B from -98 :)

The PSU seams to be fine. all WP has expected voltages. I have removed Q13-Q18 and they all tested fine. For now I have not put them back.
There is something wrong in the down converter sections. Over Fuse F1 I have -145v and in the + down converter, over the MOSFETs, I have 14.2v 143v 13.7v GDS (Q22-Q24). On the - down converter I have 145v over F2 and then -130v -142v -142v GDS over Q19-Q21. All six IRF640s test fine out of circuit.

Looking at the schematic, what cloud be the reason for these strange voltages?

I've found two e.lyts that was measuring 0uf so I replaced those. C7 and C15

This design is new to me. With the positive and negative down converter sections. Wondering what voltages should be present over JP1 and JP2 going into the drive amp section when this thing is up and running? :)

I love the electronic repair hobby and I'm trying to learn. Any input would be greatly appreciated. This thing is hooked up in a bulb current limiter and then in an isolation transformer.

Schematic is attached.

Cheers,
Daniel Elvin
 

Attachments

  • recoton_home_audio_nht_subtwo_i_amplifier_sunfire_true_subwoofer_mkii_sch.pdf
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