[Test-Equipment] Mesurements Corp Model 111-B question

[WA5CAB at cs.com]

Richard, 

I'm not familiar with the unit (specifically the vintage, which might 
answer my question) but what type crystal holder is it in?  Reason that I ask is 
that FT-243 holder crystals have a common (but usually repairable) failure 
mode.  It's probably a newer (non-repairable) type but thought I would 
mention this.

In a message dated 2011-07-16 17:07:39 PM Central Daylight Time, 
chearn at widomaker.com writes: 
> Richard,
> From my fading memory, 32 PF was the industry-wide standard value of 
> circuit shunt capacitance for crystals operating above the series 
> resonance, somewhere below the crystal's natural parallel resonance.  
> That is, the crystal reactance at the specified operating frequency was 
> inductive.  Regards, Chase/K4AFW
> 
> 
> On Sat, 16 Jul 2011 14:13:15 -0700, Richard Knoppow wrote:
> >----- Original Message -----
> >From: "Glenn Little WB4UIV" <glennmaillist at bellsouth.net>
> >To: "Richard Knoppow" <1oldlens1 at ix.netcom.com>; "Discussion
> >of Electronic Test Equipment"
> ><test-equipment at mailman.qth.net>
> >Sent: Saturday, July 16, 2011 1:38 PM
> >Subject: Re: [Test-Equipment] Mesurements Corp Model 111-B
> >question
> >
> >
> >>Send a copy of the schematic to International Crystal.
> >>They can determine the proper crystal from the circuitry.
> >>If you determine the capacitance and get it wrong, it is
> >>your problem.
> >>They can eliminate the guess work.
> >>
> >>
> >>
> >>73
> >>Glenn
> >>WB4UIV
> >
> >       I have a handbook for it, if I can find it, and could
> >send the schematic. No handbooks exist at BAMA or other free
> >sources.
> >       I think the postage for a round trip for the whole box
> >is more than the thing is worth.
> >       I tried measuring the capacitance at the crystal
> >terminals with a Boonton Q meter and with a Boonton RX
> >meter. Neither gave me a meaningful reading. A replacement
> >crystal I got from someone else is off frequency. It
> >measures the same on the calibrator, a counter with a
> >crystal tester, and on a Millen Grid Dip Meter, all the
> >same. I also get on-frequency readings from the crystal
> >tester on miscellaneous crystals including crystals for both
> >a Collins R-388 and Drake R4xB which makes me think the 10
> >mhz standard crystal is probably a 35pf (or is it 32pf)
> >crystal.
> >      This was a useful box when it worked. The trouble is
> >definitely the crystal, it oscillates with other crystals.
> >
> >
> >--
> >Richard Knoppow
> >Los Angeles
> >WB6KBL
> >dickburk at ix.netcom.com
> 

Robert Downs - Houston
wa5cab dot com (Web Store)
MVPA 9480