EEVblog Electronics Community Forum
General => General Technical Chat => Topic started by: zape on September 29, 2017, 07:19:23 pm
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This one is from the Y-sus board of the samsung plasma tv
It is 5 bands but I'm not sure which band is the first
I suspect shorted zener diode (in a parralel) but it might be just low ohm resistor.
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red red gray black black?
If black is zero, I don't think they start with black. Maybe they do
Otherwise, I think there is a slightly larger gap on the last band. Or it starts closer to the edge.
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AFAIK, there's no "black" tolerance. So the black band seems to be the first one, i.e. 018 * 10^2 = 1k8. And the red band indicates a tolerance of 2%. Still, a leading zero is unusual. I would expect brown grey black brown red.
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Looking at the E96 series, the only value that makes sense is 118 ohms (brown-brown-gray-black).
I hate these modern blue resistors. The colours used for coding are almost impossible to identify, as they seem to be partially opaque and the blue background comes through.
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Buffer IC's are bust, maybe ...
https://www.badcaps.net/forum/showthread.php?t=46761 (https://www.badcaps.net/forum/showthread.php?t=46761)
I was going to suggest checking Vs-gnd on ymain. As far as repairing the Ymain, might be easier to find a working board since this has the buffer boards integrated.
There is a kit in the UK suggesting some clues what to look for
http://www.ebay.com.au/itm/LJ41-0590...item2ee14f8e40 (http://www.ebay.com.au/itm/LJ41-0590...item2ee14f8e40)
and this comment, lease check R5085 / R5086, if there is a short across them then don't buy this kit as one or more of your buffer IC's have blown.
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After closer look I think the colors are:
black brown silver(gray) orange orange
here is the shot using better camera and no flash
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"black brown silver(gray) orange orange"
I think it is Orange Orange Gray (338), Brown = x10 then Black for 250 PPM/deg K (PPM = Parts per million)
3380 Ohms with 250 PPM temperature tolerance per deg Kelvin (i.e. Black band).
Black band information source:
https://en.wikipedia.org/wiki/Electronic_color_code (https://en.wikipedia.org/wiki/Electronic_color_code)
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I took the diode out and it was good.
Resistor measured fractions of Ohms. I have a bad multimiter so can not tell exact value. Chances are it is below 0.2 ohm
Eventually I get the TV working so I assume the Resistor is OK.
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I took the diode out and it was good.
Resistor measured fractions of Ohms. I have a bad multimiter so can not tell exact value. Chances are it is even below 0.1 ohm
Eventually I get the TV working so I assume the Resistor is OK.
Orange orange silver brown = 0.33ohm.
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I took the diode out and it was good.
Resistor measured fractions of Ohms. I have a bad multimiter so can not tell exact value. Chances are it is even below 0.1 ohm
Eventually I get the TV working so I assume the Resistor is OK.
Orange orange silver brown = 0.33ohm.
Yes, the black band on the bottom has a larger distance, than the orange bands, so it's the last band, not the first.
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I took the diode out and it was good.
Resistor measured fractions of Ohms. I have a bad multimiter so can not tell exact value. Chances are it is even below 0.1 ohm
Eventually I get the TV working so I assume the Resistor is OK.
Orange orange silver brown = 0.33ohm.
I thought it was going to be a 5 band resistor, because it has 5 bands. But apparently, the last band (if Black), can just mean something else. See picture below:
I.e. I/we needed to treat it as a 4 band resistor + 1 band of Black to decode it.
Also, I think using both grey and silver as valid colour bands, is asking for trouble (mistakes).
(https://i.stack.imgur.com/N8rMO.jpg)
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I also noticed the second orange band is wider. Does this mean anything?
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They used more paint. ;)
No. It means nothing.
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But apparently, the last band (if Black), can just mean something else. See picture below:
In power supply cirquits it is often the marking for a "fusible resistor".
http://www.mouser.com/ds/2/427/pr02fs-1103091.pdf (http://www.mouser.com/ds/2/427/pr02fs-1103091.pdf)
with best regards
Andreas
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But apparently, the last band (if Black), can just mean something else. See picture below:
In power supply cirquits it is often the marking for a "fusible resistor".
http://www.mouser.com/ds/2/427/pr02fs-1103091.pdf (http://www.mouser.com/ds/2/427/pr02fs-1103091.pdf)
with best regards
Andreas
Thanks.
An additional
black color band is applied to differentiate the PR02-FS
from standard PR02 product.
I find the quoted bit, rather confusing. Because it means that there are 5 colour bands, yet only 4 of them count and the other (Black) one just changes the type of resistor. None of the online resistor guides I could find, seemed to know about this fact.
I guess there are a massive number of traps and things, within electronics. Which can easily catch you out, until you have experienced it.
So a Black band can mean, zero (0), be a multiplier, mean a specific PPM (similar to tolerance) amount and mean it's a fusible resistor. Possible other meaning as well.
No wonder I had such difficulty interpreting the colour bands.
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I could read a 4 band resistor from 10 paces (well, not quite) .... but when these blasted 5 band blue-bodied creations began proliferating, I started keeping my meter handy to double check.
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Yeah, the color bands worked okay until the fifth one became necessary. I gave up on them after that and just check with a meter. I think the paint used was cheapened also, making all the colors much darker and hard to tell apart.
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There's always something to learn. I never would have guessed that a black ring could identify a fusible resistor.
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I never would have guessed that a black ring could identify a fusible resistor.
Just to confuse you: other manufacturers use a white or violet ring for that.
https://www.vishay.com/docs/28737/nfr25.pdf (https://www.vishay.com/docs/28737/nfr25.pdf)
with best regards
Andreas
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I had a bunch of resistors where one of the bands completely changed color when they overheated. Something to do with the pigment in that particular paint. The color change was 100% perfect, no clue at all that the band used to be a different color until we got hold of a unit with non-failed resistors.
I don't remember exactly but it was something like red to yellow on the third band. Yes, replacing them caused a few problems.
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The usual reading of the color markings are:
The first band is the nearest at the end of the component body.
The last band (if it is in same position as the first, to the other end) has a little more distance from the previous one.
When the resistor has pre-formed leads for vertical mounting, the first band is the top one. The resistor in the photo is this case, because the longer lead is insulated.
The color coding, of the bands next to the value, is sometimes very confusing; I have somewhere a few resistors of 10R and a few other bands (I don't remember how many!), that do not agree with any table. With the manufacturer unknown, to find a data-sheet, the meaning is a little dark!