Okay, this has been a productive project for me, I bought an A7 on ebay because I like them and well if you can’t open it you don’t own it right. First thanks everyone for the good information. Second here is a link to a legible copy of the SMPS schematic page.
ISO14000 is a great help and the schematics are essential though only of the power supply. His forum is in French but a few posts are English and the best images of the schematics are there.
An important post on the French forum is #80 a link to the photo from that post is below, again it is for power supply test.
I recapped my power supply before I found post #80 so I am not sure that it was failing but the power board is good now, very gratifying. I used 3, 40 Ohm 50W resistors for the loads.
I still have a problem and a photo, I will get to that. The symptom I have now is, with the A7 assembled, if I try to power up there is no response (no LED) but if I hold the power button and apply power then the LED is solid white, for a functioning A7 that means firmware update mode. The unit does not respond to any attempt to connect with a MAC or PC, however. Still maybe it is progress.
I am working toward replacing some/all of the SMT electrolytic capacitors and while inspecting I thought I could possibly see some slight bow on the top of one cap on the DSP/Amp board.
On the underside near the suspect cap I found a damaged SOT-23, Q45, marked “W3K”. Note the tiny crater where it should read 33. I am going to remove both Q44 and Q45 to try and identify the part so I can order some. I have searched online SMT part marking lists and found diodes with “W3” but no “K“. I will draw a schematic of that section of the board as well for grins.
Does anyone have a clue what cheap SMT SOT-23 part was marked with “W3K“ circa 2014?