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#1
January 3rd 04, 01:49 AM
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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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#2
January 3rd 04, 04:05 AM
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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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#3
January 3rd 04, 02:56 PM
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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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#4
January 3rd 04, 03:46 PM
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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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#6
January 3rd 04, 09:43 PM
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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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#7
January 3rd 04, 11:17 PM
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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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#8
January 3rd 04, 11:19 PM
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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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