Home |
Search |
Today's Posts |
#1
![]() |
|||
|
|||
![]()
Hello,
I am in the process of restoring an old S-120 which needed a new potentiometer. I have replaced the part w/a new one (same type) and at this moment, when I turn the radio on, I hear nothing but cracking sounds from one of the resistors nearby. I am thinking of installing a condenser (sp?) which should hold the charges from the resistors. Any idea if this should work, or am I lost out in this? Thanks, Bruno Hache (1st year Electronics Student) |
#2
![]() |
|||
|
|||
![]()
Bruno Hache wrote:
Hello, I am in the process of restoring an old S-120 which needed a new potentiometer. I have replaced the part w/a new one (same type) and at this moment, when I turn the radio on, I hear nothing but cracking sounds from one of the resistors nearby. I am thinking of installing a condenser (sp?) which should hold the charges from the resistors. Any idea if this should work, or am I lost out in this? Thanks, Bruno Hache (1st year Electronics Student) Resistors aren't supposed to make crackling sounds - ever. If it is getting hot and burning then something downstream may be shorted and drawing excessive current thru it. -BM |
#3
![]() |
|||
|
|||
![]() "Bruno Hache" wrote in message ... Hello, I am in the process of restoring an old S-120 which needed a new potentiometer. I have replaced the part w/a new one (same type) and at this moment, when I turn the radio on, I hear nothing but cracking sounds from one of the resistors nearby. I am thinking of installing a condenser (sp?) which should hold the charges from the resistors. Any idea if this should work, or am I lost out in this? Thanks, Bruno Hache (1st year Electronics Student) Why do you think it's one of the resistors? If the resistor is arcing internally, it's best to replace it. Crackling noises on these radios are commonly caused by arcing across the internal mica capacitors in the IF transformers. Robert Casey has a good article on this: http://www.geocities.com/CapeCanaver.../repair.htm#if Have you replace all the paper capacitors? Paper capacitors age poorly, and also can arc internally. All of the capacitor in a waxy cardboard tube and most of the capacitors in a molded plastic cylinder are paper. The only plastic cylinder capacitors of this era I trust are the C-D Black Cats, which are mylar dielectric. Frank Dresser |
#4
![]() |
|||
|
|||
![]()
Frank,
I haven't replaced the paper capacitors yet. I'll give it a try. I don't suspect it'll hurt the unit at all. Thanks, Bruno Hache "Frank Dresser" wrote in message ... "Bruno Hache" wrote in message ... Hello, I am in the process of restoring an old S-120 which needed a new potentiometer. I have replaced the part w/a new one (same type) and at this moment, when I turn the radio on, I hear nothing but cracking sounds from one of the resistors nearby. I am thinking of installing a condenser (sp?) which should hold the charges from the resistors. Any idea if this should work, or am I lost out in this? Thanks, Bruno Hache (1st year Electronics Student) Why do you think it's one of the resistors? If the resistor is arcing internally, it's best to replace it. Crackling noises on these radios are commonly caused by arcing across the internal mica capacitors in the IF transformers. Robert Casey has a good article on this: http://www.geocities.com/CapeCanaver.../repair.htm#if Have you replace all the paper capacitors? Paper capacitors age poorly, and also can arc internally. All of the capacitor in a waxy cardboard tube and most of the capacitors in a molded plastic cylinder are paper. The only plastic cylinder capacitors of this era I trust are the C-D Black Cats, which are mylar dielectric. Frank Dresser |
#5
![]() |
|||
|
|||
![]() "Bruno Hache" wrote in message ... Hello, I am in the process of restoring an old S-120 which needed a new potentiometer. I have replaced the part w/a new one (same type) and at this moment, when I turn the radio on, I hear nothing but cracking sounds from one of the resistors nearby. I am thinking of installing a condenser (sp?) which should hold the charges from the resistors. Any idea if this should work, or am I lost out in this? Thanks, Bruno Hache (1st year Electronics Student) First, did the radio WORK before you changed the pot???? If it was working, then the first thing you should look for is something like solder blobs causing shorts, bare wires touching where they shouldn't, etc. Pete |
#6
![]() |
|||
|
|||
![]() "Bruno Hache" wrote in message ... Frank, I haven't replaced the paper capacitors yet. I'll give it a try. I don't suspect it'll hurt the unit at all. Thanks, Bruno Hache Your crackling resistor may be a capacitor. Specifically, an Sprague Black Beauty. These had bands and looked something like power resistors. They were often used for line bypasses. Frank Dresser |
Reply |
Thread Tools | Search this Thread |
Display Modes | |
|
|