Differences between A and B models

For general discussion with your fellow Minuteman I crewdogs, maintainers and cops. Formerly Based at Ellsworth AFB, SD, Malmstrom AFB, MT, Minot AFB, ND, Whiteman AFB, MO, F. E Warren AFB, WY. On alert frm 22 Oct 1962 to 27 Sep 1974. Share your stories and meet up with an old friend.

Re: Differences between A and B models

Postby Tim on Tue Mar 16, 2010 3:16 pm

I have a few questions concerning MInute Man I:

1. In ILCS, we had a printer on the CMPG, rack to the left of the deputy's console. Did MM I LCCs have a comparable printer?

2. Per the postings in this thread, MM I LCCs could only monitor their own 10 sorties? I assume no time slot arrangements at that time?

3. I read on an online site that the guidance system on the MM I was proned to a high rate of failure (causations and rate not specified) is this the general consensus for those who were in the MM I system?

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Re: Differences between A and B models

Postby Capt. Bill on Tue Mar 16, 2010 9:09 pm

1. There was no printer to the left of the DMCCC console. There was a SACCS printer to the right of the DMCCC console and a SLFCS printer mounted above it.

2. No time slots in MM I, I assume it was direct conection from each LCC to its LFs. LFs were connecto to one or more LFs in their squadron and adjacent squadrons, this was to allow retransmission of launch and inhibit commands.

3. I am assuming you mean while on alert and not after launch. It was normal for a LF to go off alert or the crew needed to run a Calibrate on it. I don't remember how often a guidance system had to be replaced.
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Re: Differences between A and B models

Postby Tim on Tue Mar 16, 2010 9:42 pm

Ok, no printer ala DSAP or CMPG, how did you know what faults were associated with any of your LFs? VRSA? Though I understand that the VRSA panel that we had in ILCS was actually used to enable the missiles in MMI?

About the reliability of the MMI guidance system, I understand that two types of MGSs were associated with the A and B models. Just curious about your perception of failure rates/reliability during your time on crew. Montana Power was notorious about power fluctuations to both LCFs/LCCs and the LFs which seemed to cause havoc with the MMII cans. As Chief of Operations, Codes Division at Grand Forks, I thought that the MM III "cans" were more reliable based upon the number of MGS changes. Of course that is my perception and could easily be wrong on all counts.

Thanks for the information.

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Re: Differences between A and B models

Postby Capt. Bill on Tue Mar 16, 2010 11:49 pm

I don't even know what DSAP or CMPG is.

We had the MSIL, a Status Signal Receiver Fault light for each LF and VRSA for each LF. I don't remember what any of the messages were. The only missile related alarm on the MSIL was the warhead alarm.

The VRSA reset switches were used to enable the LFs in MM I and changed with the MOD.

I can really remember how the B and G missile MGS's compared, a old maintenance type might.
Last edited by Capt. Bill on Wed Mar 17, 2010 2:06 am, edited 1 time in total.
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MM III DMCCC, 742nd SMS Oct 71 - Feb 72
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Re: Differences between A and B models

Postby SAC Killer on Wed Mar 17, 2010 12:54 am

The cans in the A/B, F, and G models had similar stable platforms, but the digital computers were completely different, evolving as computer technology improved. As a result the can's physical design changed considerably as the computer became more miniaturized with each version. The reliability probably did not change much, because most can failures were caused by the moving parts on the stable platform. The reliability was very high, two orders of magnitude better than airplane stable platforms. At least, that was the case in the 80s when I last had access to quantitative data.

Not sure where the theory of power fluxes affecting the F model came from. I don't remember any issues with that when I was pulling alerts at Malfunction Junction. And would not expect any, because the LF had a motor-generator to provide stable power either from AC or DC sources. Since commercial power did not directly touch either the missile or critical ground electronics, there is no way it could damage anything.

As a historical note, the stable platform design was so good the Peacekeeper program used a similar configuration, choosing it over a star-tracker and ring laser gyro. Not bad for 1950s technology! Sometimes the ancient ways are best. 8)
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Re: Differences between A and B models

Postby Capt. Bill on Wed Mar 17, 2010 3:02 am

Tim wrote: Though I understand that the VRSA panel that we had in ILCS was actually used to enable the missiles in MMI?

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I have put this up before but here is what the DMCCC's enable/fault query panel looked like in MM I. The red covers were wired shut. At first with heavy gauge wire that you needed wire cutters for, you can see them on the left. Then someone got worried that we might lose the wire cutters and they went to thin wire you could break with your hand.

DMCCC panel.jpg
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MM I, DMCCC 741st, 742nd SMS Oct 69 - Oct 71 3 HQs and a Select Crew rating
MM III DMCCC, 742nd SMS Oct 71 - Feb 72
MM III MCCC, 742nd SMS Feb 72 - Aug 72
GT 07,08,09GM - Nov 1971 (key turned all three)
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Re: Differences between A and B models

Postby Tim on Wed Mar 17, 2010 6:24 am

Ok, now I understand. We still had the enable panel in the ILCS configuration, but used it exclusively to query for VRSA channel reports by "flipping" the red cover/toggle switch. ILCS enabled its sorties via a different panel by inserting the code through the use of thumb wheel switchs. I see from the photo what you meant by fault query. So that makes sense. If you had a fault indication on your LSMIP then you would have selected the LF in question to query for any reporting VRSA channels. Thanks for your info and patience towards a "youngster" who pulled his last alert 25 years ago!

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Re: Differences between A and B models

Postby Scruge on Wed Mar 17, 2010 2:40 pm

wblakeney wrote:I have put this up before but here is what the DMCCC's enable/fault query panel looked like in MM I. The red covers were wired shut. At first with heavy gauge wire that you needed wire cutters for, you can see them on the left. Then someone got worried that we might lose the wire cutters and they went to thin wire you could break with your hand.

DMCCC panel.jpg



So why are they numbered LF2 thru LF11... verses LF1 thru LF10 ?
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Re: Differences between A and B models

Postby Capt. Bill on Wed Mar 17, 2010 2:53 pm

Scruge wrote:
So why are they numbered LF2 thru LF11... verses LF1 thru LF10 ?


Interesting that you did not know that. In Minuteman a flight consists of one LCC and 10 LFs. The LCC is for example Oscar-01 and the ten LFs are numbered 02 to 11.

Guess your thinking of Titan that was numbered 1 to 17 since there was one missile per control center and they were one unit.
MM I, DMCCC 741st, 742nd SMS Oct 69 - Oct 71 3 HQs and a Select Crew rating
MM III DMCCC, 742nd SMS Oct 71 - Feb 72
MM III MCCC, 742nd SMS Feb 72 - Aug 72
GT 07,08,09GM - Nov 1971 (key turned all three)
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Re: Differences between A and B models

Postby Scruge on Wed Mar 17, 2010 3:18 pm

Strange inventory system. :D
Like a gun and each of its rounds of ammo being identified as b2-b7, Leaves one to believe there should be a b1.

Actually in Titan II there were 9 silos per squadron and 2 squadrons per wing except for Vandyland.
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Re: Differences between A and B models

Postby Tim on Wed Mar 17, 2010 6:38 pm

In response to SAC Killer, taking into account of the LF motor-generater providing a stable power source clears up some questions concerning commercial power surges damaging the MM IIs MGSs. The on-line article that I had read had stated that the MM I's MGS were proned to a high rate of failure out in the field. The author provided no qualifers to support this claim. I was checking with our former MMI guys to gage their perceptions. As you can see my "perceptions" can easily stray off the beaten path after all of these years. :D

In retrospect, the overall historical Minuteman alert rate (94%?) is a testiment to the design, maintenance teams, and ops crews!

As always, thanks for reaching back into "deep recesses" of your knowledge base! :D

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Re: Differences between A and B models

Postby Capt. Bill on Wed Mar 17, 2010 7:40 pm

From my memories that 94% on alert rate sounds right for MM I if not a little low. I remember that a bird being off Strategic Alert was rare and was usually when a routine Calibrate was ordered. Before they built the Uniform-01 sites on base every wing had one bird off alert that was used for training purposes.
MM I, DMCCC 741st, 742nd SMS Oct 69 - Oct 71 3 HQs and a Select Crew rating
MM III DMCCC, 742nd SMS Oct 71 - Feb 72
MM III MCCC, 742nd SMS Feb 72 - Aug 72
GT 07,08,09GM - Nov 1971 (key turned all three)
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Re: Differences between A and B models

Postby Capt. Bill on Wed Mar 17, 2010 7:40 pm

From my memories that 94% on alert rate sounds right for MM I if not a little low. I remember that a bird being off Strategic Alert was rare and was usually when a routine Calibrate was ordered. Before they built the Uniform-01 sites on base every wing had one bird off alert that was used for training purposes.
MM I, DMCCC 741st, 742nd SMS Oct 69 - Oct 71 3 HQs and a Select Crew rating
MM III DMCCC, 742nd SMS Oct 71 - Feb 72
MM III MCCC, 742nd SMS Feb 72 - Aug 72
GT 07,08,09GM - Nov 1971 (key turned all three)
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Re: Differences between A and B models

Postby Tim on Wed Mar 17, 2010 8:54 pm

I seem to recall the 94% figure while working in the Codes Division at Grand Forks. Of course the percentage could and would vary on a annual basis based upon numerous reasons. I believe that the alert rate for the bombers was in the low to mid 40%, I could be wrong on this. In MM II and IIIs no DCM worth his salt would stand idle for any sortie to be off alert....always chasing green time! At the Forks, I would get phone calls in the dead of night from job control asking for LFLC kits to be generated. Spent alot of three in the morning sessions in the CIV vault.

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Re: Differences between A and B models

Postby SAC Killer on Thu Mar 18, 2010 12:19 am

Tim wrote:In response to SAC Killer, taking into account of the LF motor-generater providing a stable power source clears up some questions concerning commercial power surges damaging the MM IIs MGSs. The on-line article that I had read had stated that the MM I's MGS were proned to a high rate of failure out in the field. The author provided no qualifers to support this claim. I was checking with our former MMI guys to gage their perceptions. As you can see my "perceptions" can easily stray off the beaten path after all of these years. :D

In retrospect, the overall historical Minuteman alert rate (94%?) is a testiment to the design, maintenance teams, and ops crews!

As always, thanks for reaching back into "deep recesses" of your knowledge base! :D

Tim, 490th SMS, Malmstrom, 1981-1985


Don't know about either the WS-133A or the LGM-30A or B, in terms of MMI. Maybe they added the LF motor-generator later. My earliest experience was the WS-133A-M with LGM-30F at Malmstrom. That system had Mo-Gens in the LCCs and the LFs.

It is also quite possible that the LGM-30A & B MGS design was more prone to failure. I got a look at one once. A lot of wired circuitry, because the printed circuit card was still in the future! It took up a lot of space, far more than the later designs. All those soldered joints were likely less reliable than the later MGS configurations, which used printed circuits.
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