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CHINA!!!! transistors!
- Thread starter KD2GOE
- Start date
sorry they where out of a cobra 142 GTL
china has been pumping out counterfeit transistors on E-bay and people snag them up...
They where all repladed at One point befor he got it.. don't know why... The pre driver and final where not the right part numbers. The solder job on it was aweful on all 3
Even if there not fake it was only letting the radio have a dead key of 4 watts with the am power cranked up and swing to 7 watts.. side band was no better with a pep of only 6 watts
Ebay= knock offs....been there, done that. Unfortunately you won't know it's a fake until you solder it in the radio. Some actually are labeled as the proper device but are far from it.
RF Parts= genuine
Fake
http://rover.ebay.com/rover/1/711-5...0001&campid=5336136228&icep_item=251208469169
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Been there, done that. I tried to fix my Uniden 76 by replacing the driver and final. I purchased them on Ebay. When I was done, the radio still didn't work. I sent it out to Bells CB and he put a good driver and final in. She is working now.
The predriver transistor (labeled C1957 in the picture) is the main reason why power output was low, since the C1957 is the incorrect predriver for a Cobra 142GTL. It should be a 2SC1973.
The C2166 and C2312 are genuine. However, it is possible the C2312 went low gain due to an SWR issue. The C2312 is a direct drop-in replacement for a C1969 and will work with same output as a C1969.
Glad you got the radio working again!
~Cheers~
The C2166 and C2312 are genuine. However, it is possible the C2312 went low gain due to an SWR issue. The C2312 is a direct drop-in replacement for a C1969 and will work with same output as a C1969.
Glad you got the radio working again!
~Cheers~
The predriver transistor (labeled C1957 in the picture) is the main reason why power output was low, since the C1957 is the incorrect predriver for a Cobra 142GTL. It should be a 2SC1973.
The C2166 and C2312 are genuine. However, it is possible the C2312 went low gain due to an SWR issue. The C2312 is a direct drop-in replacement for a C1969 and will work with same output as a C1969.
Glad you got the radio working again!
~Cheers~
yeah that may be so I did do a mix swop out where I tested 1 at a time the 2 that mad the diff where the driver and pre driver.. looking at the data sheet on the 2sc1957 looked up as just audio pre amp
lol I may have jumped the gun on china chips but it is making it hard to fined good chips now....I guess I have been lucky I have used the Ebay 1969 finals and they have worked for me everytime. I tested a old 1969 got HFE-44 and UF-648 mv the ones from ebay were HFE-171 and UF-623 mv. I am not a tech but these are the readings I got.
Chinese parts normally work well when they are not fakes being passed off as something else. Legit Chinese parts that are sold as such like HG transistors always work fine for me. There are some parts though I just want to use the real thing when I can get them which is where RF-Parts comes in!
They all come from China anyway. Unfortunately the fakes come from China also LOL.
Most real and I mean not fake Mitsubishi 2SC1969's do not have a super high HFE. That I have ever noticed and all work fine.
Most of the Chinese fake 2SC1969's do not even look like a real 2SC1969 the casing does not even resemble the real part
Most real and I mean not fake Mitsubishi 2SC1969's do not have a super high HFE. That I have ever noticed and all work fine.
Most of the Chinese fake 2SC1969's do not even look like a real 2SC1969 the casing does not even resemble the real part
