| Author |
Message |
    
Sparkomatic
Intermediate Member
Username: Sparkomatic
Post Number: 288
Registered: 10-2002
| | Posted on Sunday, May 02, 2004 - 10:49 am: | 
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Some people say that power transistors start losing power output over a period of time and others say that either a transistor works or it doesn't and there isn't any in between condition.
In the 20 plus years I have been in CB I have never burned a radio or amp up but I am curious. |
Bruce
Senior Member
Username: Bruce
Post Number: 1207
Registered: 9-2003
| | Posted on Sunday, May 02, 2004 - 11:34 am: |
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Spark YES they CAN " BE " going bad. Some transistors are realy a number of transistors bonded together and if a bond is cracked they will fail with changes like heat. Call it " Cold solder joints " but i seen it in the older VHF amps NORMALY they just go and thats it but it can happen ..... a 1307 fimal i had in a radio would go up and down in output as it got hot and hit it with cold spray poof good again........ yep enough to want one to become a bomb expert. |
Kc0gxz
Advanced Member
Username: Kc0gxz
Post Number: 785
Registered: 3-2003
| | Posted on Sunday, May 02, 2004 - 4:21 pm: |
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Bruce
You couldn't be more correct. For many years I was told and thought the same thing as Sparkomatic. Either they worked or they didn't work.
Then one day I came across a final (1307) in a Cobra 139-XLR that did just as you explained. Never again did I overlook the possibility of a final or driver breaking down internally.
Jeff. |
Kc8pcl
New member
Username: Kc8pcl
Post Number: 2
Registered: 7-2011
| | Posted on Monday, July 18, 2011 - 7:54 pm: |
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A transistor is like a light switch, it is either on or it is off, and they really don't like heat, unlike tubes that gradually loose output power over time. |
Onelasttime
Junior Member
Username: Onelasttime
Post Number: 11
Registered: 8-2011
| | Posted on Monday, August 08, 2011 - 7:05 pm: |
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They are not like a light switch. They seem to fail suddenly because of what normally takes them out. Usualy screaming high swr's due to bad ground feeding back up the power back into the transistor.
Heat slowly kills electronics. |
