Help...Sub for MRF477 or MRF497

[RODWALL]

I'm looking for one of these transistors or a good substitute for
them, it is for a HR2600. Will a SSB final from a Washington or Cobra
2000 work?
tnx Rod

[CoaxKid]

On Mon, 11 Jan 1999 00:48:14 -0500, RODWALL <ROD...@prodigy.net>
wrote:

You won't get the same power, but a 2SC2312 or 2SC1969 will work.
The pin configuration is different though.
CoaxKid dot Com

[Bill Nadzam]

I just came into a few brand new MRF-477's $38.00 each..

I know; OUCH. But thats the price.

--
=====================================
Bill Nadzam "K8WN"
mailto:nad...@bills2way.com
http://www.bills2way.com
=====================================

[nu...@nunya.com]

On Mon, 11 Jan 1999 00:48:14 -0500, RODWALL <ROD...@prodigy.net>
wrote:

>I'm looking for one of these transistors or a good substitute for
>them, it is for a HR2600. Will a SSB final from a Washington or Cobra
>2000 work?
> tnx Rod

Rod here are a few posts from my archive. I also suggest a search
using Deja News looking for MRF 477 posts.
-Dave

Motorola seem to have discontinued a lot or all of their plastic
packaged RF power transistors including the MRF477.

The MRF477 now seems to be in short supply and it has been
suggested that some outlets have been re-marking devices as
MRF477 and selling them on. These devices may be capable
of the power output but usually dont have the power gain of the
genuine Motorola MRF477. (15 db)

I've heard that there is a Japanese made TO220 transistor with
characteristics (including Power Gain) very similar to those of the
genuine MRF477.

Does anyone know the number of the device or any idea as to a
suitable replacement for the 477 ??

Spec for the Motorola MRF477 is as follows:

Power out (W) 40
Power in (W) 1.25
GPE (db) min 15 @ 30 MHz
VCC 12.5 V
Device operating frequency range 1.5 MHz to 30 MHz
Package TO220

John G3UGY

seems to be similar to BD135/BD137/BD139, they are very inexpensive
made som tests on 10m several years ago and got somewhere about 14dB
power gain in grounded collector linear amplfier.

---
DUBUS register http://www.kirsta.demon.co.uk/radio/jm-dubus.txt
Radio-Tech/waveguide http://www.users.zetnet.co.uk/ross/radio/

I ran a check and it conforms
with: MRF485 ECG 236 this is
a T-NPN, Si, VHF PO (13W at 50
MHz), TO-220

[Angel25772]

NO!! the only thing you can replace that with is a mrf 497!! YOU AN ORDER
THEM FROM rf parts for bout 40 bucks
1-800-RF-PARTS

[jim]

after reading the responses to the original post, what makes you so sure
the t0220, bd135,137,139 or mrf485 packages wont work. i am interested
in obtaining suitable subs for the 477 and if the sub does have just a
small decrease in gain then so be it. there are ways to compensate for
that.

[Dorfdog101]

477s and 497's are available from RF parts as singles and doubles, and they
have about the best prices around. I have ordered them before for 26.93 for a
477 and 29.93 for a 497.

[TRA1N]

With the all mods required to do the MRF-497 conversion, why is it that none of
you brainwaves have not mentioned the 2SC1969 modification for the replacement
of the MRF-477??????????
tr...@aol.com
tr...@pixelation.com

THOSE WHO CAN, DO
THOSE WHO CAN'T.....SEEK THOSE WHO CAN ! ! !
JUST CALL ME BUBBA ! ! ! !

[Toll Free]

I have found that the MRF455A works well, but you have to drill a hole for
the stud mount!!!

Toll Free

RODWALL wrote in message <369990...@prodigy.net>...

[Sean]

That was mentioned, along with the fact that they would do
measurably less power. Sean
>
TRA1N wrote in message
<19990115180918...@ng-fi1.aol.com>...

[Sean]

What I would like to know is, where do you find MRF 455A's at a
reasonable price at ? Sean
>
Toll Free wrote in message

[Bill Eitner]

TRA1N wrote:
>
> With the all mods required to do the MRF-497 conversion, why is it that none of
> you brainwaves have not mentioned the 2SC1969 modification for the replacement
> of the MRF-477??????????

Because we're not familiar with that mod and/or it's
still considered a big secret that the techs who know
how to perform it aren't willing to give away.

> tr...@aol.com
> tr...@pixelation.com
>
> THOSE WHO CAN, DO
> THOSE WHO CAN'T.....SEEK THOSE WHO CAN ! ! !
> JUST CALL ME BUBBA ! ! ! !

--
-------------------------------------------------------------------
-=[Bill Eitner]=-

Link to AM Tutor and rec.radio.cb FAQs:
http://home.earthlink.net/~kd6tas/
-------------------------------------------------------------------

[TRA1N]

sure it will do less on the meter but the cost difference is incredible. Power
output can ALWAYS be increased AFTER the radio if needed......but I figure
you've heard of such things being done once or twice in the past!
Good to hear from you Sean.....
tra1n

[Tommy Starr <tstarr@]

the MRF455 also is available in a surface mounting form as well..

[ICECOLDNYC]

In article <19990115180918...@ng-fi1.aol.com>, tr...@aol.com
(TRA1N) writes:

>With the all mods required to do the MRF-497 conversion, why is it that none
>of
>you brainwaves have not mentioned the 2SC1969 modification for the
>replacement
>of the MRF-477??????????

Hey Train you are back!!!! Happy New Year!!!!!!!!

ICE, ICE, AND MORE ICE MR. ICECOLD BIG APPLE TREES JUST GOT DOWN........

[Toll Free]

I don't. I had a few laying around from the "old days".

I have another Jackson that I just picked up that has a problem blowing
finals... Looking for a cheapy transistor to put in it now.

Toll Free

Sean wrote in message <77p1s2$5c7$1...@news.megsinet.net>...

>What I would like to know is, where do you find MRF 455A's at a
>reasonable price at ? Sean
>>
>Toll Free wrote in message

[dennis W. Ostrowski]

Sean wrote:
>
> What I would like to know is, where do you find MRF 455A's at a
> reasonable price at ? Sean

Westgate is not too bad....

I think I would try one of the old 2N6084 transistors for that sub if
you were going to go to all the trouble to drill a new hole.

It was a stud-mount RF device designed for use at 175 MHZ, so it has
a much higher gain at 27MHZ, and may outperform the 455 device at low
drive levels.

A side note is that since no one uses them (2N6084's) anymore, they
may be available pretty cheap!

Dennis

#12

[Toll Free]

Good idea....

I just got a Jackson that needs a final..... I just might try that one
out..

Have to put a negative feedback in now.... Stability at VHF might be a
problem with that one, though.

Toll Free

dennis W. Ostrowski wrote in message <36A373C1...@lucent.com>...

[dennis W. Ostrowski]

Toll Free wrote:
>
> Good idea....
>
> I just got a Jackson that needs a final..... I just might try that one
> out..
>
> Have to put a negative feedback in now.... Stability at VHF might be a
> problem with that one, though.

I can almost guarantee instability problems unless you do some high
frequency collector to base feedback and keep your input and output
impedances low!

But you know how to do that so you should be OK.

Dennis

#12

[rog...@my-dejanews.com]

In article <369990...@prodigy.net>,

ROD...@prodigy.net wrote:
> I'm looking for one of these transistors or a good substitute for
> them, it is for a HR2600. Will a SSB final from a Washington or Cobra
> 2000 work?
> tnx Rod
>

Contact Derrell at Valley West Electronics for help
with HR2510, HR2600 & Lincoln radios. (801) 269-0130
in the evenings(7pm - 9pm), Mountain Time Zone.

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