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I am trying to find the value of a blown resistor so that I may replace it. Its from a Circulation Booster V3 circuit board. The marking on the board where the resistor lives is marked L1 It is green and can be seen in place and burned out in picture 1. It is in close-up in picture 2.

circuit board

resister

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closed as off-topic by Leon Heller, Joe Hass, Daniel Grillo, Matt Young, Chetan Bhargava Apr 3 '14 at 17:59

This question appears to be off-topic. The users who voted to close gave this specific reason:

  • "Questions on the repair of consumer electronics, appliances, or other devices must involve specific troubleshooting steps and demonstrate a good understanding of the underlying design of the device being repaired. See also: Is asking on how to fix a faulty circuit on topic?" – Leon Heller, Joe Hass, Daniel Grillo, Matt Young, Chetan Bhargava
If this question can be reworded to fit the rules in the help center, please edit the question.

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    \$\begingroup\$ That's not a resistor, that's an inductor, hence the marking L 1. Is there any possibility you can see the colours of the rings? They contain a code which indicates the value. \$\endgroup\$ – Keelan Apr 3 '14 at 8:47
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    \$\begingroup\$ I would be concerned as to what the root cause of this fault is: the damage to that inductor is fairly catastrophic, and it could well be that it is not the only component to have failed. \$\endgroup\$ – Chris Johnson Apr 3 '14 at 8:51
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    \$\begingroup\$ What the hell is a "Circulation Booster V3"? ~~~ Edit: It's a quack medical appliance. You're not going to be able to fix it. You might be able to make it behave as it did from the factory, but it still won't work. \$\endgroup\$ – Connor Wolf Apr 3 '14 at 10:02
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    \$\begingroup\$ @PeteKirkham: If a circuit's function is to inject noticeable amounts of current to electrodes that are attached to a person, I would be disinclined to attempt any repairs. In competently-designed device, hazardous conditions will not exist absent a very improbable combination of failures. Given that known failures have occurred, and likely some unknown ones as well, I don't know how, without technical documentation, one could make sure that one isn't a single not-terribly-improbable failure away from harming somebody. \$\endgroup\$ – supercat Apr 3 '14 at 15:50
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    \$\begingroup\$ @PeteKirkham - The quack part is the part where they cite no studies, rely entirely on personal anecdotes and testimonials, and are direct-marketing a specialized "medical" device to consumers. There is literally no part of their website that doesn't scream "quack medical appliance". \$\endgroup\$ – Connor Wolf Apr 5 '14 at 0:52
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That's not a resistor, that's an inductor, hence the marking L 1. Is there any possibility you can see the colours of the rings? They contain a code which indicates the value.

There is a value calculator here, and a table here.

If you cannot read the colour code, you could try to find the assembly manual or something like this of the board and look for the L1 code.

But, as Chris Johnson says, take care: you cannot just replace the component. There might be other damage, and even if not, the cause of the damage should be investigated to make sure it will not happen again.

On a side note: how I know that this is an inductor, not a resistor? 1) because of the marking L, which is used for inductors, R is for resistors. 2) it's green, this kind of inductor is often green, resistors are often brown or blue-green. 3) you can see the copper wire inside.

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  • \$\begingroup\$ It might actually be a choke, a resistor (usually about 10 Ohms) wrapped in an inductor coil. Often found in the power input to circuits. \$\endgroup\$ – Jason Morgan Apr 3 '14 at 8:54
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    \$\begingroup\$ @JasonMorgan as far as I know a choke is an inductor, I'm not sure I understand what you mean? \$\endgroup\$ – Keelan Apr 3 '14 at 8:57
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    \$\begingroup\$ @CamilStaps: Most inductors are "intended" to have zero series resistance or parallel capacitance. Of course, neither resistance nor capacitance will ever actually be zero, but circuits are typically designed to work with any value below the specified maximum. By contrast, devices marketed as chokes are often deliberately designed not to behave as ideal inductors. It would make little sense for a coil maker to try to minimize resistance if a circuit designer was going to stick a resistor in series. If the goal is to have e.g. 10 ohms in series with an ideal inductor... \$\endgroup\$ – supercat Apr 3 '14 at 15:54
  • \$\begingroup\$ ...it's easier to construct a single "not very good" coil, possibly with an integrated resistive element, than it would be to construct a minimal-resistance coil and add a 10-ohm resistor. \$\endgroup\$ – supercat Apr 3 '14 at 16:00
  • \$\begingroup\$ I bought The item for a elderly disabled friend who lived in Spain. Unfortunately they thought the ac/dc adapter was a normal English plug and replaced it with a Spanish one and plugged it into the mains. I though that I would replace the inductor in the hope of repairing it but I don't know the specification of this component ? Thanks for your help. \$\endgroup\$ – user39718 Apr 3 '14 at 18:52

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