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

[Dave]

Hi Folks,

Thanks for the comments so far...

But first -- Geez Sorry, I didn't think I had to waste email space 
explaining about using the variac to bring this thing up.  If anyone 
wants the hairy details I will provide them off-list.

The part that is confusing to me on the LA-800D was the range of 
references implied by the front panel controls.  I think the part where 
they are frequency translated (or multiplied) is the part where the unit 
is not worting. Also suspect I have a problem in the audio amp.  Rather 
than possibly mess something up probing and testing blind, I put it 
aside until I can find more info on it.

Does anyone know what the scope display on a working unit looks like?  
Is it a circle when in lock?

Dave

 

Bill Hawkins wrote:
> 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
>
>
>
>
>
>
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