Could someone help identify this resistor? Would it help to upgrade to one with higher specs like 7w vs 5w?
A line-level mixer was plugged into a guitar amp and… it let the smoke out lol
is it a 1 kΩ, 5W? Would stepping up to 7w help with anything?
What color bands would the resistor have?
Also , Would you have the dimensions for the capacitor?
Hello @Kwazii,
This video may help you locate the capacitor.
Recommend you find a local mentor to walk you through the safety aspects of the tube-type amplifier. They are among the most dangerous consumer electronics you will encounter.
Be safe,
APDahlen
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As far as going from a 5W to a 7W (or more), it would given the resistor more head room overall.
However one would still want to make sure to check the sizes of the items being selected so they still fit into the spot on the board.
Would you have the length and diameter of the damaged resistor?
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It’s hard to tell what the colors are due to the damage but ChatGPT is confident it’s 1K 5W thanks to the schematic. The capacitor is about 22.2mm W x 35.38mm H.
ChatGPT also suggested stepping up to a 7W resistor, and 105°C cap. Is that a good idea?
1K 7 Watt part number ROX7J1K0
100uF 450V 105C 450BXW100MEFR18X30
Pay attention to the lead spacing on the cap, the above option is 7.5mm ( 0.295 inch ) and a capacitor diameter of 18mm ( 0.709 Inch )
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This should not be an issue from a specification standpoint as it would give both more operational head room.
The only thing to verify would be the dimensions of the resistor you select as the size can be influenced by the wattage.
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it’s about 24mm long x 7.9mm in diameter. I appreciate the help!
Hello @Kwazii,
What is the brand and module number of the amplifier.
We may be able to locate a schematic on the web.
Sincerely,
APDahlen
Crate Palomino V32 30 watt class A 1x12 combo amp
Hi @Kwazii,
According to this schematic, this is the screen grid dropping resistor rated at 470 Ω 5 W.
It’s normal for this resistor to run hot. However, it will run abnormally hot if the output tubes are degraded (high current) or if C16 is electrically leaky.
Recommend:
- Verify this is the correct schematic
- Verify the resistor marking on the board, you should see R9 in the silkscreen (provided it’s not been burned).
Best wishes,
APDahlen
That’s gotta be it. The board is labeled R9 and C16 is right next to it (and the other large cap is C19). Good find, thanks!
Can you go over the resistor stripe colors? I’m a little confused. I thought the colors were yellow/white/red, making it 4.9k Ω. but the schematic says 470 Ω, which i thought would be yellow/violet/brown? I believe you’re right, i’m just trying to learn
Here is a 470 Ohm 7 Watt resistor option: ROX7J470R
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Lighting things on fire has a tendency to alter their color… The color code calculator may be a helpful resource otherwise, but I’d trust a schematic over some paint that’s been heated to incandescence any day.
No. It might be beneficial in a case where a component is within sight of surviving, but the photos strongly suggest that this was not the case. Put differently, a person’s going to lose a fight with a freight train regardless of time spent at the gym beforehand.
Fair chance that there’s some other stuff broken in addition to the obvious ones when something goes toasty to the degree shown.
Bear in mind that synonyms for “artificial” as used in “artificial intelligence” can include fake, phony, counterfeit, fraudulent, imposter, hoax, bogus, sham, etc.
ChatGPT and the like will cheerfully and confidently serve up an excrement sandwich and call it nutella, with the likelihood of such outcomes increasing dramatically as the subject matter becomes more specialized and the proportion of people talking about it online when they shouldn’t be increases. Others’ mileage may vary, but I’m of the view that being qualified to evaluate the result means knowing enough that one doesn’t need to ask the question in the first place.
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Absolutely, that’s why i’m here asking the experts lol It can be amazing for some things, but i’ve seen it get things wrong plenty of times so i never blindly trust it
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Yeah, for sure best practice is to double check anything factual if you’re using an LLM to get feedback. It can make anything sound correct but junk data easily makes its way into the model, regardless of how sophisticated it is. It’s not even question of “if,” more like “when and how much?”
The evident capacitor failure gives cause to wonder if there is some installation-related matter at issue. @APDahlen has greater familiarity with the musical light bulbs than I, but looking at the schematic linked above doesn’t immediately suggest why C16 should fail.
I could imagine how some sort of input shenanigans might result in a functional short to ground that toasts the resistor (320V across 470Ω makes 217 watts) but 'lytic caps don’t usually pop like that on short notice unless they’re grossly over-volted or somehow subjected to reverse potential.
We’ve got product on the shelf mentioned above that can likely replace the burny-blowy bits, but figuring out what caused the burny-blowy situation in the first place seems like a priority.