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opusover21

40 Year old Orange - Joy!

14 posts in this topic

Ahemm this is quick post that one day i'll be able to laugh about..but maybe not just yet...

A long old weekend has been spent sweating over a soldering iron 30 odd resistors out...30 odd in...a good days intense graft...alas no sound...another long day probing, measuring pcb's in and out more time in one day than Dell.

Alas (well done Sodders) having kept all the oldie resistors and measure them off against my calcs a nice 2watter thats Blue/Grey/Brown/Gold...that third band is brown...its the same cack brown as the others that are brown...its brown i say!!

Well turns out its actually 40 year old orange...:shock: yup a day of ones life gone BUT such is the joys of DIY eh?

Its all working fine testing said rebuilt channel now....:D

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Looks orange to me.:)

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argghhh man.. I feel for you. :(

Why the hell dont they just print numbers on resistors instead

of stripes, it really is just a pain in the arse.

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scrubs wrote:

argghhh man.. I feel for you. :(

Why the hell dont they just print numbers on resistors instead

of stripes, it really is just a pain in the arse.

The colour code is usually more durable and easier to read than numbers.
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Borats Baby wrote:

oldphrt wrote:
The colour code is usually more durable and easier to read than numbers

I don't see how :

attachment.php?id=23218

Is easier to read than :

68.3 ohm .

??????

68.3 ohm ? You've misread it by a factor of 1000. It's 68k ohms.

And it isn't easy to tell the difference between 68k and 6.8k when these are printed, especially if the printing's a bit rubbed and/or scratched and/or dirty. Furthermore if the component is soldered to a pcb it's all too easy for the printing to be hidden round the back. Capacitors are commonly printed rather than banded and working out their value from the obscure microscopic hieroglyphs on them can be a nightmare.

Valvebloke

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Valvebloke wrote

68.3 ohm ? You've misread it by a factor of 1000. It's 68k ohms.

And it isn't easy to tell the difference between 68k and 6.8k when these are printed, especially if the printing's a bit rubbed and/or scratched and/or dirty. Furthermore if the component is soldered to a pcb it's all too easy for the printing to be hidden round the back. Capacitors are commonly printed rather than banded and working out their value from the obscure microscopic hieroglyphs on them can be a nightmare.

Valvebloke

Point taken ...

I can't read resistor values and used a table to get to 68.3....... obviously can't read tables either...........

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opusover21 wrote:

Better pic...all orange apparently! none of these are brown bands! Ahh well its all a learning experience

If the thing is working OK a quick test with an ohmmeter after removal would have told you what the resistance is. The orange brown brown one is a big clue, 310 ohm isn't a common value.
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earlofsodbury wrote:

For ordinary mortals, not gifted with supernatural colour acuity and the ability to memorise a counter-intuitive colour-banding system which is rarely well implemented, this is a common slip-up. In isolation, one manufacturers' orange can look like brown, never mind when things age. Plus, bands can be so evenly spaced it's not even clear which end to read from! Even had that problem with diodes, never mind resistors! Factor in age, wear and tear, bad printing and differing background colours, and it's an area where mishaps are inevitable, hence why measuring and carefully noting all values is vital when doing dismantling to upgrade .

Modern surface-mount resistors are too small for this system, and so may use numbers - sometimes with a multiplier/divider, more unhelpfully without, and in many cases there is no indication whatsoever what the value is! Given that lifting them to measure them is often to destroy them (or at least render them unreliable), and it's clear why tweakers hate the damned things...

Everyone that services anything with surface mounts must hate them for their unserviceability. It's unserviceability and far too cheap consumer electronics that finished the trade for me as a living.

On the other hand the colour code system actually works really well and normally makes it easy to tell at a glance what the values are.

How can Sodbury accuse me of trolling if he can't even read my posts? I think we should be told!!

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Borats Baby wrote:

Valvebloke wrote
68.3 ohm ? You've misread it by a factor of 1000. It's 68k ohms.

And it isn't easy to tell the difference between 68k and 6.8k when these are printed, especially if the printing's a bit rubbed and/or scratched and/or dirty. Furthermore if the component is soldered to a pcb it's all too easy for the printing to be hidden round the back. Capacitors are commonly printed rather than banded and working out their value from the obscure microscopic hieroglyphs on them can be a nightmare.

Valvebloke

Point taken ...

I can't read resistor values and used a table to get to 68.3....... obviously can't read tables either...........

You read it perfectly, you just needed to know that the 3 represented the number of zeros you chuck on the end.;-)

As someone who was first taught this in a Post Office Telecommunications lab in the early 80's, I have no problem with the colour coding system. However I did have the means to double check resistors, capacitors and inductors with the appropriate measuring tools and the service manuals we possesses for all kit we worked with. I suppose that does take the stress out of being greeted with a burned or discoloured resistor. Like Fred, I changed profession when modern kitbecame surface mount and simply disposable when it broke. An example is the Avometer. A wonderfully engineered analogue measuring set that was designed to last forever with the appropriate maintenance. You go from that to a cheap plastic multimeter that was cheaper to replace at the end of its calibration period than to send away for calibration! I know he doesn't need any, but in Freds defense when you work with the colour code system daily for x years (12 in my case) it really doesn't present too much in the way of challenges.:cool:

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