Electronics > Repair
Help me understand this complex flyback PSU
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shakalnokturn:
Same here, a few too many things look too iffy on the schematic.
Assuming all the rest tied to the oscillator section is for secondary side OVP/ OCP / thermal shutdown I'd just go by R16 / C5 for the operating frequency calculation.
F1GWR:
Had a check about my reverse engineered schematic. Made some minor corrections to the daughterboard schematic. New one is uploaded in my initial message with name: "Schéma_fille".

As for the T1-T2-CR1 section couldn't find any mismatch. But I agree there seems to be no output (apart from acting directly on power supply lanes).
Maybe anyone wants to check the above assertion with the enclosed PCB pics.

Motherboard changes in schematic will follow later (will modify transformer faulty connections and check in the triac section the weird: "both anodes linked to ground!")... (to be cont'd next post)
F1GWR:
(cont'd from previous post)

...and PCB routing in Kicad (warning: components references in yellow are placed outside and consequently maybe superimposed over a neighbour!)
F1GWR:
Base chopper (SchemaHacheur) schematic has been corrected due to inconsistencies and also hidden tracks on the PCB. New diagram has been dropped in the first message attachement of this thread in order to avoid confusion with previous wrong data. Sorry for these mistakes.
Triac circuit has been bebugged, but still does not seem correct...
F1GWR:
Hi folks,
After :box: a long time against this SMPS, it came to life again :phew:.

In summary:
1- main board 330K, 1/2 or 1 W start-up resistor R2 was open circuit; replaced by a bigger 2 W one
2- protection triac SCR2 was routed the wrong way (Artesyn swapped A1 and G  :palm:); could not find a reverse TO-220 equivalent, so I had to lift pins 1 & 3 and solder wires to swap connections (fortunately the hack is now hidden 8))
3- some parts of the circuit are stlll a mystery...

Green LED was lit. All P1 output voltages checked quite accurate with no load (except maybe -18 V measured at -19 V, quite acceptable)

See below waveforms of the HiPot (Ch1) and U1 output (Ch2). 0 V reference = bottom. Trigger point: start of 2nd div. Supply voltage: 15 VDC.

HP 35670A test log now reveals DSP error 6 (X/P RAM address test). If valuable info I'll start a specific thread...

Thanks to all that involved in this repair.  :)
And hope that my reverse engineering schematics will help others in case of this PSU failure...
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