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I'm trying to repair a power supply that someone cooked by running on UK mains with a travel adapter rather than a stepdown transformer.

I've found an area of clearly burnt components that I want to replace but I'm not sure what they are or how to read their ratings.

photo 1

I believe the components at Z1,2,3 and 4 are possibly varistors, they're marked V470 A7, I can't find any that match online so maybe I'm reading that wrong but photo 2 might show you better

photo 2

I believe the component at ZD1 is a diode (possibly a TVS diode) but that's all I know though it seems to be marked Z1056 (there might be more markings under).

As for the items in C2 and DSP1 I have no ideas at all.

Any help anyone can give identifying and helping source replacements will be greatly appreciated, thanks for your time.


I removed the components for better photos. Any help identifying these components for replacement (after a burn) would be greatly appreciated.

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This one I think is a varistor, markings seem to be an "m" logo followed by "V470" (maybe 670??) Followed by "A7" or maybe "/7" underneath.

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Next up this little green thing, has bands like a resistor but I'm not convinced it is one, not seen one like it before.

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This one I think might be a voltage suppression diode maybe? It's marked with "Z1056", then a large "S" or "5" followed by a little "1AD".

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Last up we have this, it looks sort of like a resistor except it seems almost like the shell where the bands are is see-through and there's something at its core.

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And finally some photos of the board for context.

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  • \$\begingroup\$ (Has the fuse been blown? I'd expect less damage "further down" if it was.) \$\endgroup\$
    – greybeard
    Commented Mar 8, 2023 at 17:12
  • \$\begingroup\$ There's a glass fuse just partially visible in both photos and its shattered but looks like it didn't blow quickly enough to protect these first in line components, i'm hoping the damage is limited to those which is why i'd like to replace them all but can't identify them to source them \$\endgroup\$ Commented Mar 8, 2023 at 17:30
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    \$\begingroup\$ @KidCreation - Hi, As I explained on your new question today that was effectively a continuation of this one, with additional photos, so I have added them here. I note that you ask for help sourcing replacements, but recommendations like that are off-topic here, as they quickly become obsolete, and are often not useful outside of one country / region. An identification question is on-topic, though as I mention before, those should be limited to one component. If this is voted closed as "needs focus" you may need to step through one component at a time. Thanks \$\endgroup\$
    – SamGibson
    Commented Mar 11, 2023 at 17:58
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    \$\begingroup\$ "little green thing" appears to have a board-label of "C2" so it is likely a capacitor of value 0.1 microfarads. Glass-enclosed component that you identify as resistor-shape might be a spark-over suppressor. Could all this damage be caused by a nearby lightning strike? These components accept power from outside, perhaps through long wires that act as lightning antennas. Their intent is to suppress voltage spikes. \$\endgroup\$
    – glen_geek
    Commented Mar 11, 2023 at 18:03
  • \$\begingroup\$ The damage was caused by someone connected a 100V appliance to 240V mains, so i guess somewhat similar effect to a lightning strike \$\endgroup\$ Commented Mar 11, 2023 at 18:07

2 Answers 2

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Those appear to be Panasonic ZNR transient/surge absorbers.

V470 should be a 47 volt 250 amp version, part number ERZV05D470.

Don't go by me, double check and verify before ordering.

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  • \$\begingroup\$ Thanks, nobody else looks to be suggesting anything so I'll go with that, any idea on the other components? \$\endgroup\$ Commented Mar 10, 2023 at 20:11
  • \$\begingroup\$ @KidCreation Nope, sorry. \$\endgroup\$
    – GodJihyo
    Commented Mar 10, 2023 at 21:46
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The TVS diode is a Semitec Z1056.

The glas component marked DSP is a surge absorber: Mitsubishi DSP-301N

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  • \$\begingroup\$ Wow, thanks for that, are they specifically rated components or do I need to find ones of those which match the spec (if that makes sense) for example on rs components that mitsubishi part claims to be 300v which seems high considering it's a 24v supply to the board. Or does that simply mean the part can handle that much of a surge? \$\endgroup\$ Commented Mar 17, 2023 at 21:23
  • \$\begingroup\$ Not sure what you mean by "specifically rated", but a different part with similar specs will be fine. For the TVS a P6KE56A would work, for example. I don't really know much about glass discharge tubes, so I'm not really sure why this one chosen here. \$\endgroup\$
    – nanash1
    Commented Mar 18, 2023 at 9:35

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