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Author Topic: Motorola brick amplifier  (Read 5544 times)
W4CPT
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Posts: 17


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« on: April 30, 2004, 08:31:43 PM »

Need information on Motorola N1274A and N1275A amplifiers. A schematic diagram or at least the rf transistors used in these models.  The 1274A is VHF and the 1275A is UHF I think. Any information on these amps is greatly appreciated. I have searched Motorola data bases with no luck. These amps were built around 1997 or 98.
Randy
KI4BQN
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SU1KA
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Posts: 3




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« Reply #1 on: May 19, 2004, 07:14:06 AM »

I have on of those motorola Amplifier
 its great one , run with 12V 10 Amp
1-5 in   10-50w Out
 very suitable to use it with HandHeld
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W9DML
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Posts: 3




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« Reply #2 on: June 11, 2004, 08:54:59 AM »

still need specs?

daVe
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KD5HQL
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Posts: 3




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« Reply #3 on: July 10, 2004, 01:00:48 AM »

I don't have a schematic for the Motorola N1274A Amp.  But I would be interested in knowing if it can be used for 2 meter (144-148) Amateur band.  The label on one selling on Ebay states 150.8 - 174.  The seller claims 136-174.  http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=5709045521&category=48700

Any help is appreciated.

Mark
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KC2MMI
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Posts: 621




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« Reply #4 on: July 14, 2004, 09:47:48 PM »

I picked one of these up and could use any specs or information available. Especially, which of the power pins are pos and neg?
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W9GB
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Posts: 2598




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« Reply #5 on: August 25, 2004, 10:29:46 AM »

These commercial VHF amplifers use a 4-pin "Jones" connector.  These are readily available (e.g. Mouser, Tower Electronics (www.pl259.com), some Radio-Shacks do carry them).  A VOM or VTTM in continuity to case will confirm the negative lead (13.8 VDC).  If I remember correctly, you wire the hot to 2 pins and the black (negative) to 2 pins.

Motorola RF amplifier designs are largely based upon the work of Helge Granberg W7ES (sk) at Motorola.  Schematic can be found in the Motorola VHF Amplifier Application Notes.

Bat Labs (www.batlabs.com) is the web site for surplus Motorola gear, information, forums and modifications.

w9gb
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KD5ZZZ
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Posts: 1




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« Reply #6 on: January 23, 2005, 06:53:29 PM »

if you have the scamitics to the motorola n1274a vhf 136-150mhz i sure could use a copy. thanks john kd5zzz
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KB5YLG
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« Reply #7 on: April 30, 2006, 12:41:36 PM »

I got one of these off Ebay, and hooked it up today.
Got 40W out with 2W in.  Got nearly 100W out with 6W in.  On 144.490.  Seems to work good.

David
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KD5BYB
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Posts: 16




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« Reply #8 on: May 28, 2006, 06:39:57 AM »

I just bought one of the N1274A versions off of eBay and hope to try it out today.  Seems like a nice little amp to use with an HT.

I've scanned the sheets I got with the unit and posted them on my webpage at:

<http://bellsouthpwp.net/k/d/kd5byb/N1274A/Motorola%20N1274A.pdf>

If anyone has additional info, I'd love a copy!

thanks and 73,
ben
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KD5HQL
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Posts: 3




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« Reply #9 on: May 28, 2006, 12:05:31 PM »

Ben,
 
Which model of the N1274A brick Amp did you get?  Was is it the NLD7701A 136-150.8 or was it the NLD7702A 150.8-174?
 
Marco
KD5HQL
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KD5BYB
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Posts: 16




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« Reply #10 on: May 28, 2006, 01:07:52 PM »

Hi Marco,

I've got one of the NLD7702A units (150.8 to 174 MHz) - apparently they can be retuned for 2M use, which is what I'm hoping to do.

thanks and 73,
ben
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KD5HQL
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Posts: 3




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« Reply #11 on: May 28, 2006, 01:58:44 PM »

Ben,

When you find a way to do it, would you please let me know.  Do you plan on sending it back to Motorola or to a service shop to perform the adjustment or do plan on doing it yourself?

Marco
KD5HQL
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KD5BYB
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Posts: 16




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« Reply #12 on: May 28, 2006, 02:21:05 PM »

Hi Marco,

I intend on doing it myself.  If you download the limited data I have on my webpage (see a few posts ago) you'll see there are instructions for tuning the amplifier included.  (oops!  the original scan was missing this exact page, go back and download if you don't have the page with the tuning instructions)

However, I have yet to see if:

1)  The two tuning caps have enough range to tune to the 2M band and,

2)  If the harmonic filter as-is will be appropriate for the 2M band.  I hope to get out my L-C meter and take measurements of the components used.  I will then model the filter to see what sort of performance it has as-is.  Maybe no changes will be required for 2M.

I have no doubts that the amp itself is okay for 2M - apparently it is a very wide-band design at heart.

thanks and 73,
ben
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KC2MMI
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Posts: 621




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« Reply #13 on: May 28, 2006, 06:06:25 PM »

Ben, that PDF file is mainly unrenderable here in gen-you-whine Adobe Acrobat. Page 2 can render, pages 1 & 3 show up as blank. Can you try remaking the PDF, and if you are using the latest Acrobat, enable the compatibility settings (i.e. "Use Acrobat 4.0 format" or whatever you have like that) ?

It's a common Acrobat problem, Adobe *dis*abled compatibility with older versions as a default, probably to force everyone to upgrade every year.<G>

I've got one of the 2-meter model and they are vey nice units, I'd just like to get the technical info--which no one else has gotten their hands on for YEARS
now!

Thanks.
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KD5BYB
Member

Posts: 16




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« Reply #14 on: May 29, 2006, 08:30:28 AM »

The PDF file is unrenderable?  Really?  It was made with Adobe Acrobat 7.0.7, which I understand is the latest.  I also thought that they fixed the backwards compatibility problem in 7.  Interesting.  Should be four pages total - maybe I've totally hosed something up?

Let me check and I'll see if I can find the 4.0 option.  If I can, I'll reupload.  If I can't, I'll convert it to 4 JPEGs or something else.

thanks and 73,
ben
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