i need help with my amp..2 resistors are charred, heres a pic:



as you can tell from the pic, i cant tell what the resistor's ratings are..do the numbers next to it say anything?

you cant see it on the pic but under the left resistor it says R606 and next to the right resistor is says R604..

if i were able to get the right resistors, u think i would be able to solder it myself? is it that hard to do something this small? thx for your help..hope to hear back REALLY soon cause i have a show this friday!! well wish me luck and thanks for your support!

 

Those look pretty screwed. Your best bet unless you can get an identical amp to check the resistor rating, use the rating from # 603 that isnt burned out, if it seems like it is the same as the others. Looks like you fred the ones for that one transistor. You might get lucky and have the amp work after replacing these or you may find other power issues that aren't readily visible. If it were mine I would probably try replacing those burnt ones since they are cheap and see if it works. If not turn it into the company that makes it and suck up the $100 it will probably cost to have fixed.

5g

what kind of amp is this? and what did you do to get it to blow?

 

now i gotta find an identical amp..can i just..guess? lol what if i use the same resistance rating as the resistors on the transistor to the left? what would be the problems if the resistance was too low or too high?

i just hope it's not the transistor there cause that's a little more costly than a couple resistors..

it's an alpine amp and if they just had a frickin parts list like panasonic does, i would be happy cause then i could just look that part number up. but nope, they dont..online at least. i guess ill call them tomorrow. and the thing is the nearest authorized repair shop is in minnesota (dont ask me why) and i dont have time to send it since it takes 5-7 days to repair and additional time to send back..

well thx for your help and answer my questions if u can! thx again!

 

I would say you may be able to get away with using the same resistances as R605, but it's a long shot even if that is the right resistance. First, there's a reason those burnt out - they obviously aren't supposed to. That reason won't magically go away. Also, that PCB may be a multi-layer board, in which case, the burning on the board may have caused more than just visible damage if other layers have problems. Also, soldering new resistors in place will be more difficult and less user-manageable with a multi-layer board.
-N

 

If the colour bands are brown, green, black, and silver like they LOOK in that picture, then your resistor is:
15 Ohms
10% Tolerance

For the couple of cents per resistor that will cost, buy a few of them and give it a try.

 

the color on the resistors to the left were brown black black, so they are 10 ohm...and im pretty sure the burned out ones and the resistors to the left are the same since they both go to their seperate transistors and the transistors on the other side also has the same resistors for each transistor.

im gonna give it a try either way, and i dont think it's a multilayer board..all the soldering is done underneath so..i dunno. but im not the most experienced person with this but i think i can do it. thanks for all your help!

oh yea, i think i know why they burned out..i was kinda pushing the amp hehe..it's 4 ohm rated when bridged and i used a 2 ohm resistance on it, it doubled the wattage and im pretty sure that's where the problem came in. Thanks again for all the help!

 

ok i bought some resistors at radioshack but they had 10 watt, 1 watt, 1/2 watt and 1/4 watt resistors..but from the size i went with 1/2 watt but when i compared the resistors in the amp were a lot smaller..do u think i should go back and buy the smaller ones? im pretty sure they were rated less wattage..but im not sure what the wattage means when it comes to resistors

 

just go with the higher wattage. it means that it will be less resistant to do exactly what happened. you exceeded the current handling for those resistors and they burned out. getting higher wattage will eleviate this problem, though it will allow the problem to propogate through the rest of the circuit....so it's up to you. be careful when soldering htem on too that you don't burn them out with too much heat. if they are soldered on the bottom of the board and not surface mount...probabyl the best thing to do is to desolder the ones you have from the back, just heat em up and push em out, then solder in the new resistors. can you see the copper leads on the back of the board? if when you solder into the holes it doesn't work, try scraping some of the surface coat off to get to the copper leads and solder it CAREFULLY onto those coming from the holes. the key to soldering is enough heat that you get a good bond between the two materials, but not too much that you burn out the component. it's not like soldering wires together, components are more fragile. put the resistor in the hole or on top however you are gonna attach it, heat up the two materials you want to bond (the resisitor lead and hte metal hole) for a couple seconds then add your solder to the metal, not the iron. if it's hot enough the solder will melt and bond to the metal, it should be a quick procedure. it may take some practice. i've done lots of circuit boards and the most important thing is patience.

 

1 suggestion to add to what Cup said... it really is important not to burn out the componenets, especially the transistors and the leads that connect to them will carry heat very well. Try to grip the leads on them or other nearby components with some needlenose pliers - that will dissipate the heat into the pliers (make them act as a heatsink) so that all that heat isn't dissipated in the component.

If you're not particularly experience at soldering, it will take a few tries and it will heat up a lot more than someone more experienced, so this heatsink idea may save it if it can still be saved..
-N

 

call or email the company that makes the amp and ask for a schematic of the amp and it should give you the values and location for each resistor. the R606 means that it is resistor number 606 on the amp circut board and i am sure if you had the schematic on the amp then you would be able to fix it. also ask the company if they can send you a resistor or two with the schematic. sometimes they will and sometimes they wont, but it never hurts to try. i have encountered this problem often and have had to fix it. the reason for it is usually running you amp over its expected load. for instance, you can not run 2 ohm mono on a 4 ohm mono amp, the circuts will overload and it will do just what yours did. make sure your loads from your speakers match the allowed load for the amp. good luck

 

ok..bad news it didnt work..something went wrong i probably broke it more..o well. thanks for the advices but i missed them lol.

gourry, thats the next thing on my list. i will do that ASAP or just buy a new amp but i should at least try saving my amp first. thanks for all your help!