[time-nuts] LAVOIE LA-800D WWV Timebase Receiver

[Bill Hawkins]

Dave,

Please, folks, don't just turn on a piece of vacuum tube equipment.
That could burn out an irreplaceable power transformer. If you do
not have equipment to test for shorts or bad electrolytics, then
make a jig with a light bulb socket to put the bulb in series with
the line. Start with a 40 watt bulb (CFLs won't work) and work up.
If the bulb is always bright, don't apply line power to the set.

I sold my LA-800 last spring. Don't remember what paper went with it,
but I had the schematic at one time. Sadly, my "filing" system does
not make it possible to retrieve anything without going through all
of the paper collected over 25 years. Try Manuals Plus.

The standard input on the left of the panel feeds selected multipliers
that produce 10 MHz. This is fed to a phase shift network such that
the scope produces a circular sweep at 10 Mc (circles per second).
Sounds like the horizontal scope amp is dead, if you supplied a local
standard signal and the multipliers worked. The 90 deg phase shift only
produces a circle at 10 MHz.

The WWV section on the right side only receives 5 or 15 MHz. Some magic
is used to get 10 MHz out of either carrier. This is used to intensity
(Z input) modulate the circle. Dunno why they don't receive 10 MHz.

Several years ago, here in MN, I had an HP-103 as the standard and was
listening on 5 MHz. Propagation was such that WWV would alternate with
the female voice at WWVH. The bright half of the circle would change
sides, illustrating the phase shift with distance. Neat stuff.

I'm willing to help you get this fine receiver back in action.

Nice workbench.

Bill Hawkins bill at iaxs.net

-----Original Message-----
From: Dave
Sent: Sunday, December 20, 2009 4:03 PM

Hi Timenuts,

My first email to the list.  I've had this LAVOIE LA-800D (see picture) 
receiver for about 10 years now.  Before that, it was sitting in an 
ariplane hanger for some unknown number of years and was headed for the 
trash when I aquired it.  Well,  I finally put it on the work bench and 
was quite surprised that I was able to power it up without anything 
exploding.  I've determined that it will receive WWV on 5mc quite well 
and produce a vertical deflection on the scope.  I can hear a very weak 
400hz on the speaker.  I can also feed 400 kc into the local standard 
input and see it getting filtered and amplified internally.  This is a 
far as I can get.  I am not sure how this device is suppose to work but 
am fairly certain that most of it is functional.  I really need to find 
schematics and some operating instructions to make it work all the way.  
I've already done the quick google and other customary searches for info 
without avail.  If anyone out there could email me pdf's of the 
schematics, and other manuals it would help me a lot in getting this 
classic piece of equipment back in operation.  Pointers to info would 
also be appreciated.

Thanks,

Dave