Sir notallbad . . . . .
Let me provide a close together view of the two board sides with a color coded mark up of the principal components of interest.
I additionally provided a nearby, viewable schematic of a typical application note from that LNK364's IC's manufacturer
I dood it . . . . .in my interpreting it as best as I could, with it using a NON CONTRASTING foil pattern of two shades of green . . . further
impacted upon, with both sub par edge lighting and glaring central light reflections.
BASIC DESIGN CONCEPT . . . . .
Looking at the top left corner of the center photo, we see the switch mode power transformer that is going to be handling both variable
width and bursts of square waves in the 10's to 100's of K's frequency . . . . it is being power demand specific.
Possibly 2 diodes of a discrete build up of 4 for a a FWB rectifier, reside at the left of the power transformer. Then I seem to see the PINK RECTANGLE electrolytics with mid RED RECTANGLE 1 MH inductor making a pi filtering network for creating raw DC.
In AMERIKANSKI use, I expect a developed ~160 raw DC being delivered, if being You-Are-A-Peeing voltage , I am expecting twice that level . . . . and if you touch it . . . . .You . . . .
Will-Be-A-Peeing . . . . . a la Delmer Dumbnuttz.
GIVE us the capacitances and voltage ratings of the two E-caps just covered . . . I now see 10's @ 400VDC listed above . . ., and
ALSO, those of the nearby C23 and C22 , which must be related to filtering the output of the secondary of the power transformer, as being derived from some unviewable Schottky rectifiers.
That is being one of the units raw DC power supplies, you also have a minor ancillary one made up of the . . .refer to schema . ..CY type of poly cap that uses its capacitance reactance to voltage and power drop down the rawline AC from its left lead connection, and then out, to flow thru to the D5 diode to then create a minor DC supply. It associates with the VR1 zener and the LED within the U2 optical isolator to regulate against overvoltage when the LNK initially powers up . Then the LNK overrides and provides the required / demanded power level.
I estimate that there will be two power supply levels created and am so using a RED draw in of the 16 VDC supply output.
It might be 12 or 15VDC , you will just have to confirm . . . as I currently think that your LNK circuitry is not working. ***
Also on the foil side of the board I see what probably will be a U4 5 volt three terminal regulator associated with being the u/p supply source and probably the before and after E-caps that I have YELLOW RECTANGLED at the center bottom of the PCB.
(Give those Cap/Voltage ratings . . . along with the two that are near the LNK cluster.
Of course, the other YELLOW markups are being the LNK and the 817 optical isolator for regulation feedback.
And there is the YELLOW markups of your burnt open resistor . . .I have seen many different values being used.
TRY THIS ONE . . . .
Take your pulled original . . .HIGHLY likely .. . of being a metal film resistor and jump short its two ends together and connect to one of the leads of an ohmmeter set to low scale ohms. Take a naked #11 Exacto blade and grip it in constant contact with the other ohmmeter lead and initially stab to the paired resistor leads, to confirm near zero ohms continuity.
AND THEN . . . .you gently scrape at
MID point of the resistor to just easily creep thru the conformal paint coating and then I heavily suspect an ohmic reading will appear .
Double that resistance value and it should be right at your original resistors value.
No workee ? then move down to the " quarter " distance portions from the ends and compute accordingly, on a found resistance completion..
The RED circled BLUE device "foil path reads" it as being a line spike MOV.
If you now have full raw DC voltage thru the primary of the power transformer to the 364's internal PWR FET, but with no developed secondary supply DC voltage from the transformer secondary . . . . . inform us and come back for our testing of the 364 and . . . .The Rest of the Story. . . . .
Gud . . . Day . . . .
YOUR TECHNO REFERENCING . . . . .
73's de Edd
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i fullie souport publik edekashun.