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Old January 3rd 04, 01:49 AM
Jim Flanagan
 
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Default Heathkit SB series LMO Schematic Request

Hello..
I have been looking 'high and low' for a copy of the LMO
schematic for the SB line of radios. I tried all of the Heath forums
that I am aware of. Does anyone know where there exists (not BAMA)
a schematic of the solid state (heck, I would take the tube version)
version of the LMO. I would have thought that after all these years
someone would show up with a copy of the schematic as well as the
alignment instructions. I realize that Heath never made public this
information, but I would have figured somebody would have reverse
engineered these units and documented what he/she discovered.
If I had a dead unit, I would take on the challeng and make
public my findings.

Anyone with any knowledge regarding aligning the units?

Thanks..

Jim Flanagan
wb5kye
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Old January 3rd 04, 04:05 AM
Harold E. Johnson
 
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"Jim Flanagan" wrote in message
tt.net...
Hello..
I have been looking 'high and low' for a copy of the LMO
schematic for the SB line of radios.


I have the schematic of the LMO. It is on a "D" size print, but is so old
and the paper was not acid free that it's very yellowed. Just barely able to
make it out and certainly not xeroxable. Give me a snail mail address and
I'll send it to you, but I'd like it back when you finish with it.

W4ZCB


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Old January 3rd 04, 02:56 PM
N2EY
 
Posts: n/a
Default

In article et, Jim Flanagan
writes:

I have been looking 'high and low' for a copy of the LMO
schematic for the SB line of radios.


It was published in QST when the SB-100 was reviewed. However, note that the
LMO was made by several different manufacturers to Heath's specs and that there
may be significant internal differences. Heath simply specified the dimensions,
connections, tube type and electrical performance, and left the rest up to the
subcontractor. They treated the LMO as a "component", just like the crystal
filters or the power transformer.

Good luck!

73 de Jim, N2EY
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Old January 3rd 04, 03:46 PM
Rob Dunn
 
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Jim,

No first hand experience but if you go to BAMA ( bama.sbc.edu ) and download
the SB-101 technical description (it is in deja vu format) you will find the
LMO schematic on Heath manual page 151 (deja vu page 35). A description of
the function is found on Heath manual page 132 (deja vu page 14). Then if
you download the SB-100 alignment instructions, again from BAMA, you will
find a short instruction on adjusting the frequency shift control of the LMO
in the SB-100 alignment proceedures. This is all for the 6CB8 tube
version.

If you go to http://www.qsl.net/k5bcq/sb104/sb104.html you can find a great
Adobe Acrobat schematic of the SB-104A that includes a solid state LMO
schematic including the plug pinout. I have a separate JPEG of the LMO
clipped from this schematic if you have trouble. Whole schematic is 1.45
MB. JPEG is 640kB.

Hope that helps.

73, Rob Dunn, KD7HRN


"Jim Flanagan" wrote in message
tt.net...
Hello..
I have been looking 'high and low' for a copy of the LMO
schematic for the SB line of radios. I tried all of the Heath forums
that I am aware of. Does anyone know where there exists (not BAMA)
a schematic of the solid state (heck, I would take the tube version)
version of the LMO. I would have thought that after all these years
someone would show up with a copy of the schematic as well as the
alignment instructions. I realize that Heath never made public this
information, but I would have figured somebody would have reverse
engineered these units and documented what he/she discovered.
If I had a dead unit, I would take on the challeng and make
public my findings.

Anyone with any knowledge regarding aligning the units?

Thanks..

Jim Flanagan
wb5kye



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Old January 3rd 04, 09:41 PM
Jim Flanagan
 
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Hi Rob..
Thanks. I went ahead and got a copy of the SB101 tech and made a
copy of the schematic. I will now redraw the schematic into Protel and
attempt to come up with the resistor/capacitor values and include those
into the schematic. After that I will attempt to come up with an
alignment procedure that will, hopefully, usable to the heathkit nuts..
Look for the schematic to be posted at BAMA in the future..

Jim

In article k.net,
says...
Jim,

No first hand experience but if you go to BAMA ( bama.sbc.edu ) and download
the SB-101 technical description (it is in deja vu format) you will find the
LMO schematic on Heath manual page 151 (deja vu page 35). A description of
the function is found on Heath manual page 132 (deja vu page 14). Then if
you download the SB-100 alignment instructions, again from BAMA, you will
find a short instruction on adjusting the frequency shift control of the LMO
in the SB-100 alignment proceedures. This is all for the 6CB8 tube
version.

If you go to
http://www.qsl.net/k5bcq/sb104/sb104.html you can find a great
Adobe Acrobat schematic of the SB-104A that includes a solid state LMO
schematic including the plug pinout. I have a separate JPEG of the LMO
clipped from this schematic if you have trouble. Whole schematic is 1.45
MB. JPEG is 640kB.

Hope that helps.

73, Rob Dunn, KD7HRN


"Jim Flanagan" wrote in message
tt.net...
Hello..
I have been looking 'high and low' for a copy of the LMO
schematic for the SB line of radios. I tried all of the Heath forums
that I am aware of. Does anyone know where there exists (not BAMA)
a schematic of the solid state (heck, I would take the tube version)
version of the LMO. I would have thought that after all these years
someone would show up with a copy of the schematic as well as the
alignment instructions. I realize that Heath never made public this
information, but I would have figured somebody would have reverse
engineered these units and documented what he/she discovered.
If I had a dead unit, I would take on the challeng and make
public my findings.

Anyone with any knowledge regarding aligning the units?

Thanks..

Jim Flanagan
wb5kye








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Old January 3rd 04, 09:43 PM
Jim Flanagan
 
Posts: n/a
Default

In article k.net,
says...
Jim,

No first hand experience but if you go to BAMA ( bama.sbc.edu ) and download
the SB-101 technical description (it is in deja vu format) you will find the
LMO schematic on Heath manual page 151 (deja vu page 35). A description of
the function is found on Heath manual page 132 (deja vu page 14). Then if
you download the SB-100 alignment instructions, again from BAMA, you will
find a short instruction on adjusting the frequency shift control of the LMO
in the SB-100 alignment proceedures. This is all for the 6CB8 tube
version.

If you go to
http://www.qsl.net/k5bcq/sb104/sb104.html you can find a great
Adobe Acrobat schematic of the SB-104A that includes a solid state LMO
schematic including the plug pinout. I have a separate JPEG of the LMO
clipped from this schematic if you have trouble. Whole schematic is 1.45
MB. JPEG is 640kB.

Hope that helps.

73, Rob Dunn, KD7HRN


"Jim Flanagan" wrote in message
tt.net...
Hello..
I have been looking 'high and low' for a copy of the LMO
schematic for the SB line of radios. I tried all of the Heath forums
that I am aware of. Does anyone know where there exists (not BAMA)
a schematic of the solid state (heck, I would take the tube version)
version of the LMO. I would have thought that after all these years
someone would show up with a copy of the schematic as well as the
alignment instructions. I realize that Heath never made public this
information, but I would have figured somebody would have reverse
engineered these units and documented what he/she discovered.
If I had a dead unit, I would take on the challeng and make
public my findings.

Anyone with any knowledge regarding aligning the units?

Thanks..

Jim Flanagan
wb5kye






By the way..
The SB104 used a less expensive LMO due to the fact that there was
no need for a linear tuning characteristic. This is because having a
digital readout meant that it wasn't necessary..

Jim
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Old January 3rd 04, 11:17 PM
Michael Black
 
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N2EY ) writes:
In article et, Jim Flanagan
writes:

I have been looking 'high and low' for a copy of the LMO
schematic for the SB line of radios.


It was published in QST when the SB-100 was reviewed. However, note that the
LMO was made by several different manufacturers to Heath's specs and that there
may be significant internal differences. Heath simply specified the dimensions,
connections, tube type and electrical performance, and left the rest up to the
subcontractor. They treated the LMO as a "component", just like the crystal
filters or the power transformer.

Good luck!

73 de Jim, N2EY


I remembered that, but when I set out to post it, I suddenly wasn't sure
if I was remembering properly. I sure couldn't place where I read it,
but I suspect it was that QST review.

Michael VE2BVW

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Old January 3rd 04, 11:19 PM
Chuck Harris
 
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Default

Jim Flanagan wrote:

By the way..
The SB104 used a less expensive LMO due to the fact that there was
no need for a linear tuning characteristic. This is because having a
digital readout meant that it wasn't necessary..

I was so disgusted with the poor stability and linearity in my SB104's
VFO that I designed a simple VCO that used a 10T pot as the drive. It
was more stable, quieter, and easier to tune than the original... I
wonder what I did with those schematics?

-Chuck Harris

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