I HAVE A QUESTION???

[ramblingman]

I was wondering do any of you guys happen to know,
what a suitable sub would be for the RM-3 Transistor.
These are the new type transistors used in the KLV amps.
I have a KLV-250 amp here,With no TX.after checking out
i found all four transistors bad.I am wondering if i might
have a direct replacement/suitable sub here i might use.
I have several irf-520 s here,as well as some erf-2030 s,
which are the new mosfets.And i believe that the RM-3s are
mosfets as well.I have checked N.T.E.s cross-reference site,
but no help there.The RM-3 that they have listed,turned out
to be a diode.Oh yeah/ by the way the Rm-3 IS A TO-220
Case transistor.Any help is appreciated............Ramblingman

[WARLORD136]

i have an answer.the rm3 can be purchased at copper electronics.com. their part no. is w90-20040, and sells for $7.50.

[Rick]

It must be very hard to do a search on this forum, as know one check it out and ask the same questions over and over.

www.radiomods.co.nz/forum/viewtopic.php?t=2243

[ramblingman]

Well thanks guys..Yes i knew i could get them at coppers.
You can also get them at h and y.And they are less than
5 bucks each there..But i was just wondering if one of
these mosfets i already have would work..Instead of having
to wait on the others to be shipped..It was not a matter of
price,seeing they are only 5 bucks each.It was just a matter
of availability..But i checked with the guys at cb tricks forum
and they said the irf-520 s would work as sub..So all is well.
Thanks again for replys.................ramblingman

[Rick]

The right MOSFET to replace the RM3 is HUF75343P3.
Amps using the RM3 have been around in the UK and Europe for over ten years now.
The IRF520 will work but with lower power output and how it will last is any ones guess.

You can find the datasheet at this URL
http://www.datasheetcatalog.org/datashe ... 5343P3.pdf

www.datasheetcatalog.org/datasheet/fairchild/IRF520.pdf

If you wish to do the right job you the right device.

There are to many people guessing about MOSFET’s, one think I keep coming across is that the ERF2030 is the same as the IRF520, but they are not, if you put them on a transistor curve tracer you will see that they are not the same device and do not match.

[ramblingman]

Alright rick,,So do you think the erf-2030 would be a better
replacement than the irf-520.Or neither of them would be
good..As far as these rm-3 s,this is the first time ive ran
across this transistor.Expesically in a amp..Of course this is
the first one of these k.l.v. amp ive ever fooled with..
I have been using one personnaly for about 4 years now.
And never had any problems with mine..But this one belongs
to a c.b. friend of mine.So im just trying to help him out with it.
I usually dont fool with amps much at all..And all the ones ive
worked on has used the sd1446/2sc2879 or 455s.
Thanks for the input...............ramblingman

[ramblingman]

Well guys,i guess you could say you never know till you
try..I tryed the IRF-520s in the K.L.V 250.And it did work,
but like rick said..It did not do the wattage as a amp with
the RM-3s in it.And also they seemed to run hotter than the
RM3s..With a radio keying 1 1/2 watts and swinging 8 watts,
the amp with the IRF-520s-dead keyed 5 watts with swing
to 55 watts on the low side.And on the high side it dead keyed
25 watts with swing about 100..The same radio setup driving
my K.L.V 250 with the original RM3s-dead keys 25 and swings
to 80 on the low side,and dead keys 50 and swings 150 on the
high side..So the moral to the story is..These two trannies are not
the same..The IRF-520s are about 25% below power output vs.,
the RM3s.And apparently are not as heat sensitive.Due to the fact
of after about 3 minutes holding dead key on each unit..The unit
with the 520s was so hot you could not hold your finger on the
final holddown tab washer..And the unit with the original RM3s
with the same 3 minutes dead keydown,the washers over the finals
were barely warm..So i ordered several new RM3s today..

[James Unit 198]

Rick is more often than not on the ball.

James.