Another tragic victim of resistor code dyslexia

[Mark Hammer]

I etched a GGG board for the Boutique Bender/Tonebender several years ago, and have been trying to get it to work ever since.

I tried everything.  I checked the board over and over for bridges, cracks, and cold joints.  I double-checked the transistor pinouts.  I verified the hfe of the transistors (2SB33).  Back and forth, forth and back.

Poking through the bin-o'-boards today, I thought I'd give it another try.  I got....something....but it was negligible.  Tried yet another transistor. The controls worked as they should but it was the wimpiest sound imaginable.

Twisting the board around to get at something, though, I thought I noticed something that just looked...weird.

R1 showed stripes of brown...check....green....check...black...check...gold....check....and, hey wait a sec.  Brown GREEN black?  Isn't that supposed to be brown black green?  Sure enough, I had a 15 ohm resistor where a 1M should be.  Swapped in the right part for the wrong one, and wham-o-blammo... beautiful sizzling blood-curdling fuzz!

I'm thinking that someone back at the store, where you pick the parts from the bin yourself, had inadvertently placed the 15R resistor in the 1M bin via the same mistake I did, and when I reached into my own drawer of "resistors higher than 500k", I just looked for the right colours, but not necessarily in the right order.

But right now, I'm a happy boy.  That's one nice fuzz. 

[Govmnt_Lacky]

Good to hear that you were able to get that one runnin' 

It has become automatic for me to verify each and every resistor color code PRIOR to placing them into my "for use" bins.

Have yet to be bit by that since instituting that small step.

That... and ALWAYS being careful when I pull from the bins as not to mix them with the adjacent values 

[LucifersTrip]

that sounds great (probably literally)...i'm sure this is a good post for the newbies to read.

though, wouldn't voltages have shown a problem right off?

[Mark Hammer]

Voltages?  I don't need no steenking voltages!!

That was actually going to be the next step.  I usually start with the visual.  And since the transistors were from the bargain bin, I ended up treating them as suspect.

[R.G.]

You can tell GREEN from RED visually???

Wow. A lot of the time I can't. 

[Mark Hammer]

Oh yeah, colours are dead easy.  It's the first, second, third thing that I have such a hard time with apparently.

That might explain why I have such difficulty getting my socks over my shoes in the morning.

[Govmnt_Lacky]

That might explain why I have such difficulty getting my socks over my shoes in the morning.

Just remember...

The color code goes RED, BLUE, YELLOW from the knee to the ankle.   

[gritz]

My sympathies Mark - problems like that really demonstrate the subtle difference between looking and seeing.

I have some old stock .6W resistors and the bands are so thin that it's almost impossible to tell the difference between the purple, brown and red. Add the 1% tolerance (reddish brown) and the temp. coefficient (brownish red) bands to the mix and I'm reaching for the meter every time. I'll be glad when they're all gone!

[alparent]

Old age! It's sad what it can do to you!
If  you ever need someone younger to help you out with things like these!..........I'd be glad to help you! 

[digi2t]

Last month, poor Paully spent weeks pulling his hair out trying to get his Vocalizer working. Jimi and I went full tilt trying to give him clues to get it working... but no dice. Finally, it got to the point where I offered, and he accepted, to send it to me, all the way from Arizona. After carefully checking each component, it turned out there was a 15 ohm resistor where a 15K was supposed to be. Gold band, instead of red. In the end, we were just happy to find it. But, it reminds us to always test, or be observant, or lose more hair

[Mark Hammer]

I'm just about ready to buy one of those magnifying viewers with the circular fluorescent bulbs that you can clamp to your bench.  Not much of a cure for stupidity, but at least when good sense strikes, decent lighting will let you take it a little farther.

[digi2t]

I'm just about ready to buy one of those magnifying viewers with the circular fluorescent bulbs that you can clamp to your bench.  Not much of a cure for stupidity, but at least when good sense strikes, decent lighting will let you take it a little farther.

Got one at Home Depot over the Christmas holdays. 70 bux I think. I love it. Especially useful for inspecting my soldering for bridges. One of my best buys of the year 2010.

[boogietone]

I'm just about ready to buy one of those magnifying viewers with the circular fluorescent bulbs that you can clamp to your bench.  Not much of a cure for stupidity, but at least when good sense strikes, decent lighting will let you take it a little farther.

Gonna add this to my list. I have a mix of carbon and metal resistors. What a pain in the a$$ with the extra band on the metal. Not complaining, but it makes me think measure twice and select twice when searching for a particular value.

[Nasse]

I used to have handheld spot-light to check critical markings, helps sometimes. But they make those small markings and text smaller and smaller every year which is true, seen it in the old days. I also triple check with multimeter.

[PRR]

> You can tell GREEN from RED visually??? Wow. A lot of the time I can't

Where do you drive? I want to avoid all traffic-lights in your area.

I assume you jest. There IS a common color-blindness with these symptoms; but I'd think by now if you had it you'd know all about it.

> viewers with the circular fluorescent bulbs

I can ace any color-blind test. But remember that most fluorescents make hardly any red light. I'm always uncomfortable reading Red and Brown under Fluorescent. A little incandescent nearby makes a lot of difference. (So does skylights in your shop, in day-time, not counting the leaks and hornets.)

[teemuk]

I always test them with multimeter before they go in. I have never managed to read the colour codes in wrong order but I often do have BIG problems in distincting brown from red, red from orange, orange from yellow, green from blue, and blue from purple. Poor lightning and super thin stripes doesn't really help too much in that. Sometimes it's also hard to figure out from which way to actually read the damn colour coding. So, I always measure them to make sure it's indeed what I interpreted.

[scratch]

when I started work for a computer company right out of college, I had to get  full eye exam ... apart from needing glasses, I found out I was red/green deficient which explained my trouble with the red/green/brown/orange ... colour bands. Traffic lights are not a problem, I guess the wavelengths are such I have no trouble distinguishing them.

I too have taken to measure and bin all my resistors, or I leave them in there original package and reseal as appropriate.

[Perrow]

I changed a 330k resistor, to a 330 ohm resistor just last night. Though I'd have to blame the idiot who converted the schematic to the layout I used if it wasn't me who did that too. After I found the solder bridge the thing even worked

[Tony Forestiere]

> You can tell GREEN from RED visually??? Wow. A lot of the time I can't

Where do you drive? I want to avoid all traffic-lights in your area.

Easy. Top light is RED, Bottom is GREEN! (At least it is in the US).

[WGTP]

I try to do that stuff early in the day when the light comes in the East window and my eyes and brain are fresh.  I also like the nice little LED flashlights and keep the VOM close.  If all else fails, I go to the kitchen and dump everything on the counter or get my 18 year old son to check it out.