Re: Interesting DC-DC converter circuit
@stj: Thanks for the link to "diode gone wild". He provides the name of the topology (self oscillating flyback converter) and a good explanation for how it should work.
@sam: I've checked C103 again and got the following:
C103, Spec: 470uF 35V, measured 450uf and ESR .17 ohms (in circuit)
I'm going to try replacing it since it does seem to be on the borderline.
Thanks, -Reed
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Re: Interesting DC-DC converter circuit
A bit more context. Dates at ~1995. I've tested the transistors and diodes in circuit. All seem fine. I've checked the ESR of C103, it's showing .11 (good). D3-D6 are labeled "37JPH-". I haven't been able to figure out what they are, but they all have a forward voltage of 0.52V. Outputs are something like 6V@100ma, +15V@20ma, -15V@10ma so I'm guessing total output is under 1W. One interesting point is that a couple of the SMD components have come loose from the PCB and had to be resoldered, so I touched up all the SMD parts. I know...
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Re: Interesting DC-DC converter circuit
I should also mention that the other side of the opto-isolator is just connected to the DC output on the secondary side.
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Interesting DC-DC converter circuit
The attached snippet is from a AC Technology Corp M1230B MC Adjustable AC Drive 3 HP low voltage supply. Link voltage is good at 380VDC. The converter won't start. I'm trying to figure out what you would call this topology so I can search for some theory on how it works. I'm guessing that it's some kind of resonant converter but I haven't been able to find anything like it. Seems like there are not enough parts on the primary side......
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Re: Need Help debugging Delta Products ADP-200DFB (iMac A1311)
I've updated my schematic. Is there a way to update or replace attachments?
Using the schematic that SAM_SAM_SAM linked to I was able to figure out the boost circuit is indeed running. I just need to get the input voltage high enough to get valid Vcc.
Boost begins at ~90VAC input. 200VDC on C1.
Gate drive on Q2, Bursts of 192KHz @ 13.6Vpp
So now I need to figure out the PWM circuit. I see no gate drive on Q1 & Q3. I haven't found any pinout or datasheet for DAP015AD, but...
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Need Help debugging Delta Products ADP-200DFB (iMac A1311)
I need help identifying and finding a pin out for IC31, DAP017A (PFC I think) and IC32, DAP015A (PWM controller I think). A schematic would also work but from my searching on this forum, they don't seem to be available. I have a self drawn schematic which I've attached below. Both parts seem to be in SOIC16 packages. I can't seem to get any PFC boost out of this unit even though I have changed all the bad components I could find:
F1 open
Bridge rectifier, BD1, T4KB80F is shorted.
Q1,Q3, SPA07N60C3 open.
Any further troubleshooting tips would be wel...
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Re: Someone have schematic to Apple iMac Power Supply
I'm also looking for Power Supply Schematic with boardview for ADP-200DFB (iMac A1311) or datasheet for IC31, DAP017A (PFC I think) and or datasheet for IC32, DAP015A (PWM controller I think). In this case I found:
F1 open
Bridge rectifier, BD1, T4KB80F is shorted.
Q2, SPA15N60C3, appears to test good.
Q1,Q3, SPA07N60C3 open.
I've replaced the bad parts but still don't see any PFC boost. My usual debugging approach relies on having a rough idea, from either datasheet application schematics...
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Re: New Members - please post your introductions here
I'm an old electronics hobbyist who enjoys keeping broken electronics out of the land fill. Looking forward to contributing.
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