Hi

 I should have access to the supply dump some time in November.
 My take was that they started off with a more exotic PCB approach
 early on and simplified things a few years later. If I remember
 correctly
 the solder mask changed a bit at the change over as well.

 Bob

 <mailto:huszaghmatt@gmail.com>> wrote:

 so I can’t

 the reason

 design and

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Hi Adrian, Rick, Bob, The "flex" board is a thin ribbon-like PCB. It's shown in the manual [1] and described in the HPJ article [2], pages 26-28. Jack Kusters (1937-2012) -- of SC-cut, 10811, 5071A, and GPSDO SmartClock fame -- once told me the flex board seemed clever at first but was prone to fail when used in instruments on [military] aircraft due to prolonged exposure to vibration. Or something like that. I'm not sure if that anecdote is related to the question here. I too would like to see a tear-down of the two oscillators mentioned. /tvb [1] 10811A/B Oscillator Operating & Service Manual: http://hparchive.com/Manuals/HP-10811AB-Manual.pdf http://leapsecond.com/museum/10811a/10811a.pdf [2] Hewlett Packard Journal, March 1981: https://www.hpl.hp.com/hpjournal/pdfs/IssuePDFs/1981-03.pdf https://archive.org/details/Hewlett-Packard_Journal_Vol._32_No._3_1981-03_Hewlett-Packard On 8/24/2022 1:24 PM, Adrian Godwin wrote: > If it's not too off-topic, what is a 'sculptured' flex circuit ? > The 10811 I've taken apart has a 2D-shaped and folded flex circuit > that I'd consider 'conventional' - does a sculptured one have some > integral 3D shaping ? > > > On Wed, Aug 24, 2022 at 7:46 PM Bob kb8tq via time-nuts > <time-nuts@lists.febo.com <mailto:time-nuts@lists.febo.com>> wrote: > > Hi > > I should have access to the supply dump some time in November. > My take was that they started off with a more exotic PCB approach > early on and simplified things a few years later. If I remember > correctly > the solder mask changed a bit at the change over as well. > > Bob > > > On Aug 24, 2022, at 6:13 AM, Matt Huszagh <huszaghmatt@gmail.com > <mailto:huszaghmatt@gmail.com>> wrote: > > > > Bob kb8tq <kb8tq@n1k.org <mailto:kb8tq@n1k.org>> writes: > > > >> There are at least two *very* different 10811 PCB’s out in the wild > >> in quantity. I don’t have access to the “stockpile” right now > so I can’t > >> say how the one in the picture compares to the commonly seen > >> varieties. > > > > If you do get access at some point and it's not too much trouble to > > check, I'd be interested to know more about this. Do you know > the reason > > for having two versions? Is it simply that one was an earlier > design and > > the other replaced it? > > > > Thanks > > Matt > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > <mailto:time-nuts@lists.febo.com> > To unsubscribe send an email to time-nuts-leave@lists.febo.com > <mailto:time-nuts-leave@lists.febo.com> >

Conventional flex is the same thickness everywhere, same as PC board. Sculptured has variable thickness. I'm not really an expert on this. --- Rick Karlquist N6RK On 2022-08-24 13:24, Adrian Godwin via time-nuts wrote: > If it's not too off-topic, what is a 'sculptured' flex circuit ? > The 10811 I've taken apart has a 2D-shaped and folded flex circuit that I'd > consider 'conventional' - does a sculptured one have some integral 3D > shaping ? > > On Wed, Aug 24, 2022 at 7:46 PM Bob kb8tq via time-nuts < > time-nuts@lists.febo.com> wrote: > > Hi > > I should have access to the supply dump some time in November. > My take was that they started off with a more exotic PCB approach > early on and simplified things a few years later. If I remember correctly > the solder mask changed a bit at the change over as well. > > Bob > > On Aug 24, 2022, at 6:13 AM, Matt Huszagh <huszaghmatt@gmail.com> wrote: > > Bob kb8tq <kb8tq@n1k.org> writes: > > There are at least two *very* different 10811 PCB's out in the wild > in quantity. I don't have access to the "stockpile" right now so I can't > say how the one in the picture compares to the commonly seen > varieties. > If you do get access at some point and it's not too much trouble to > check, I'd be interested to know more about this. Do you know the reason > for having two versions? Is it simply that one was an earlier design and > the other replaced it? > > Thanks > Matt _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe send an email to time-nuts-leave@lists.febo.com _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe send an email to time-nuts-leave@lists.febo.com

Hi Tom: Interesting comment about flex circuits. Fig 2 in the HPJ article 1981-03 shows components on the flex. I see flex circuits in a lot of  military hardware but they are used to replace cables, not hold circuit elements.  For example: PSC-2 Digital Communications Terminal (DCT) https://prc68.com/I/Images/PSC2-13b.jpg -- Have Fun, Brooke Clarke https://www.PRC68.com axioms: 1. The extent to which you can fix or improve something will be limited by how well you understand how it works. 2. Everybody, with no exceptions, holds false beliefs. -------- Original Message -------- > Hi Adrian, Rick, Bob, > > The "flex" board is a thin ribbon-like PCB. It's shown in the manual [1] and described in the HPJ article [2], pages > 26-28. > > Jack Kusters (1937-2012) -- of SC-cut, 10811, 5071A, and GPSDO SmartClock fame -- once told me the flex board seemed > clever at first but was prone to fail when used in instruments on [military] aircraft due to prolonged exposure to > vibration. Or something like that. I'm not sure if that anecdote is related to the question here. I too would like to > see a tear-down of the two oscillators mentioned. > > /tvb > > [1] 10811A/B Oscillator Operating & Service Manual: > > http://hparchive.com/Manuals/HP-10811AB-Manual.pdf > http://leapsecond.com/museum/10811a/10811a.pdf > > [2] Hewlett Packard Journal, March 1981: > > https://www.hpl.hp.com/hpjournal/pdfs/IssuePDFs/1981-03.pdf > https://archive.org/details/Hewlett-Packard_Journal_Vol._32_No._3_1981-03_Hewlett-Packard > > > On 8/24/2022 1:24 PM, Adrian Godwin wrote: >> If it's not too off-topic, what is a 'sculptured' flex circuit ? >> The 10811 I've taken apart has a 2D-shaped and folded flex circuit that I'd consider 'conventional' - does a >> sculptured one have some integral 3D shaping ? >> >> >> On Wed, Aug 24, 2022 at 7:46 PM Bob kb8tq via time-nuts <time-nuts@lists.febo.com <mailto:time-nuts@lists.febo.com>> >> wrote: >> >>     Hi >> >>     I should have access to the supply dump some time in November. >>     My take was that they started off with a more exotic PCB approach >>     early on and simplified things a few years later. If I remember >>     correctly >>     the solder mask changed a bit at the change over as well. >> >>     Bob >> >>     > On Aug 24, 2022, at 6:13 AM, Matt Huszagh <huszaghmatt@gmail.com >>     <mailto:huszaghmatt@gmail.com>> wrote: >>     > >>     > Bob kb8tq <kb8tq@n1k.org <mailto:kb8tq@n1k.org>> writes: >>     > >>     >> There are at least two *very* different 10811 PCB’s out in the wild >>     >> in quantity. I don’t have access to the “stockpile” right now >>     so I can’t >>     >> say how the one in the picture compares to the commonly seen >>     >> varieties. >>     > >>     > If you do get access at some point and it's not too much trouble to >>     > check, I'd be interested to know more about this. Do you know >>     the reason >>     > for having two versions? Is it simply that one was an earlier >>     design and >>     > the other replaced it? >>     > >>     > Thanks >>     > Matt >>     _______________________________________________ >>     time-nuts mailing list -- time-nuts@lists.febo.com >>     <mailto:time-nuts@lists.febo.com> >>     To unsubscribe send an email to time-nuts-leave@lists.febo.com >>     <mailto:time-nuts-leave@lists.febo.com> >> > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe send an email to time-nuts-leave@lists.febo.com

Tom Van Baak via time-nuts <time-nuts@lists.febo.com> writes: > I too would like to see a tear-down of the two oscillators mentioned. I'm not sure yet whether mine classifies as one of these two, but I'd be happy to do a teardown of mine and share the pictures, if anyone is interested. Matt

There's also a hybrid approach, where flex material is used as the inner layers of a multi-layer PCB, with what is an undoubtedly complicated multi-step manufacturing process to ensure that the individual rigid PCB elements can ultimately be routed free of the rigid layer, while the flex layer remains intact. I have one example that has seven interconnected rigid elements, and to me it seems to be a solution in search of a problem. I can't see how the ridiculous cost of manufacturing such an assembly would offset the cost of using "traditional" flex and flex connectors. If the flex portion gets damaged, the entire assembly is junk. In my case, someone opened the housing containing the rigid/flex monstrosity with a sharp tool, slicing one of the flex layers, severing over 30 traces that spanned between two PCBs. - Keelan On Wed, Aug 24, 2022 at 11:26 PM Brooke Clarke via time-nuts < time-nuts@lists.febo.com> wrote: > Hi Tom: > > Interesting comment about flex circuits. Fig 2 in the HPJ article 1981-03 > shows components on the flex. I see flex > circuits in a lot of military hardware but they are used to replace > cables, not hold circuit elements. For example: > PSC-2 Digital Communications Terminal (DCT) > https://prc68.com/I/Images/PSC2-13b.jpg > > -- > Have Fun, > > Brooke Clarke > https://www.PRC68.com > axioms: > 1. The extent to which you can fix or improve something will be limited by > how well you understand how it works. > 2. Everybody, with no exceptions, holds false beliefs. >