Replacing the MRF477 with a 2SC1945 in a President LINCOLN. As long as the output circuit of the transceiver has no other faults results are good and since m…
Replacing the MRF477 with a 2SC1945 in a President LINCOLN. As long as the output circuit of the transceiver has no other faults results are good and since m…
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hello mark can you help me ? i need a good replacement to a MRF440 do you
now any ? 73
What’s a Lincoln?
Excellent, another lincoln saved thanks to help from the video, 10W am/fm,
approx 16 ssb pep.. great stuff using the 2SC1945..
@Flashvette See the web page for TX alignment for the HR-2510 under UNIDEN
at CB-Tricks as before, it explains how to set the bias current.
@guamiranga00 This video is for a 2SC1945 not a 2SC2312!!!!
@emercito The problem with this transceiver is it was not designed for a
MOSFET device and it is more difficult to convert than you may think, many
people have tried and failed which is why i just use a 2SC1945 bi-polar
transistor as it is easy and simple with very little modification and the
result is good. The other problem is the the IRF520/IRF640 type MOSFET’s
were not designed as RF linear devices and are a poor substitute for the
originals.
As always, a very good video with great information conveyed here. I always
thoroughly enjoy these video’s and have learned much from watching and
listening 🙂
Could you make a Fet mode on this transceiver? I have got this equipiment 5
years ago and the final stage has burned and i did something like CBTRICKS´
website sucssessfully with irf 640, but incorrect biasing lead the fet
itself destroyed.
I replaced mine 15 years ago with a mrf497 and a diferent driver, used a
fan on the back and got 60Watt SSB out of it instead of the 40Watt with the
mrf477
@weazle66 thanks for that weazle is there any or parts can u think of that
would need replace or is it to hard to say or less u seen it . thanks agine
aaron
Got the 1945 transistors and I’m geting 20 watts on my htx100 thanks
@guamiranga00 You can use 2SC2312 to replace 2SC1969 as these transistors
are very similar – see below. 2SC1969 = B C E 12db 2SC2312 = B C E 10.5db
2SC1945 = B E C 14.5db MRF477 = B E C 15db
@guamiranga00 I use 2SC2312 transistor to replace 2SC2312 not 2SC1945, the
2SC1945 is common emitter transistor and 2SC2312 is not so is not really
suitable. 2SC2312 = B C E 2SC1945 = B E C I have
2SC2166/2SC1969/2SC2312/2SC1945/2SC2078 etc transistor so i do not need to
use other to replace.
Weasle. After you remove the bias test point jumper. How to you set the
bias current before you put the jumper back in. Is there a pot to turn to
adjust the current?
Thank you sir I all ready purchase the 2sc1945 from your eBay store. and if
you get the new replacement for the mrf477 will buy it thank you so much
for your videos and all the info that’s on your videos .soon I will post a
video of my moded to portable back pack htx100
@djaaron2006 I would not like to say without doing some tests on the radio,
if it is just the driver and/or final then it will still TX enough power to
be heard on another radio close by – if this is the case then you can check
if the driver and/or final are blown by checking the bias current on each
using the service manual. The bias current should be around 50-60ma (SSB
-TX no audio) – if you can’t set the bias correctly then this usually
points to a bad transistor.
@urbex2007 The LINCOLN is a CPU controlled radio and the TX switching is
via the CPU so may not be a transistor or could even be a dry joint, i take
it you have checked out the mic in case its a fault there.
I’m amazed you fitted the new part without renewing the thermal grease. The
metal heatsink face behind the transistor has a cast finish (uneven) so you
absolutely have to fit thermal compound to fill in the microscopic air
gaps. I would have polished (smoothed) the chassis metal behind the
transistor and still used a thin coating of grease. I saw poorly fitted
transistors like this all the time.
You already tested a 2SC2312?
hello weazle i have a emperor shogun that i got of a mate he says he put +
to – and – to + ni when i trun the radio on there not power out put do u
think if i put a 2SC1945 in it would this fix my proleam ? thanks for any
help aaron
@djaaron2006 Hi Aaron, the 1945 does work as a sub for the 477 in the
Shogun but as it has reversed polarity it may have damaged other parts as
well so it may need more than just the final.
@G0HZU Who say’s i never put any thermal grease on the transistor? You
Maybe?… unlike those that cover the transistor in it and make a a mess i
just put a small dab on the back of the fin so when the transistor fixing
screw is tightened up the grease spreads under pressure so just enough to
do the job but without looking a mess!…. oh and i get people who never
think or ask before they speak all the time!!
@weazle66 Thanks a lot!!! 73!
Like always good videos mate I am on need of 2sc1945 to replace the final
of my htx100 I found the replacement on eBay from the roc And of course
they are fake 1 the position of the bce are backwards 2 the rf power
limited 2.5 /3 watts max if you have them let me know how to buy them much
thanks sir
Ok, but you’ve already tested with 2sc2312 or know if it works well in
place of 2sc1945?
Great info…thanks, cheers & beers…….390
@zx636racer So you got a cheap 2SC1945 and it was fake – what a surprise!,
I sell real 2SC1945 transistors on Ebay – look for seller “weazle66”, soon
i may also have a MRF477 replacement to. I have seen fake MRF477/MRF497
transistors on Ebay very cheap and lots of people are buying them but it
won’t be long before they know what they really have!!
Definitely solved! I did not realize the difference between ECB and BEC.
Now you know Transverter the CTE, the TR-45? He uses in output, a pair of
2SC1969 who are burned, and was wondering if putting a pair of 2SC2312
would gain any real or not. Thanks!