[Boatanchors] HP-8708A Synchronizer?

[Ian Wilson]

I downloaded a copy of the manual from Artek. Very nice. More than
reasonable
price for this obscure piece of documentation. Highly recommended.

73, ian K3IMW



On Mon, Mar 31, 2014 at 11:14 AM, Pete Lancashire
<pete at petelancashire.com>wrote:

> If you interested in what the combination can do, HP had a App Note
>
> http://www.hparchive.com/Application_Notes/HP-AN-71.pdf
>
> I have a 608E / 8708A set up as part of my BA/Vintage bench. Have not tried
> it with a 606B since I don't have one.
>
> Artek has the digital/PDF version of the manual
>
> One can also sync the 8708A to an external 20 MHz (take that 10 MHz  from
> your Cs, Rb or GPSDO and 2 x it).
>
> Cost 608E $20, 8708A $25, keeps the BA bench warm in the winter, last year
> at  a Ham Swap there was a
> basically new condition 606B that sold for $40.
>
> Practical .. nope, but this is BA
>
> A non BA solution would be to create your own error signal to drive the
> 606B/606E.
>
> -pete
>
>
>
>
> On Mon, Mar 31, 2014 at 10:44 AM, David C. Hallam <dhallam at knology.net
> >wrote:
>
> > The +300V supply is used as a reference for the 25.6V supply.  The filter
> > capacitor in the +300V is a dual section 120/40 uF twist lock.  There is
> a
> > 1/4 A fuse in the negative line which is grounded after the fuse.  I
> > thought it was a little unusual in the fact that the negative of the
> > capacitor was not connected to the can.  Since the can is isolated from
> the
> > capacitor and it is mounted on a phenolic wafer anyway, I didn't see why
> > the can should be insulated.  Try to find an insulated dual section can
> > with the negative not connected to the can of the correct size to find in
> > the existing mounting brackets!  I finally bought a suitable replacement
> > from AES.  Reamed out the hole in the bracket enough to allow me to wrap
> > the can with vinyl tape.  Since the can was mounted on a phenolic wafer
> > anyway, I didn't worry about the can being the negative connection.
> >
> > David
> > KW4DH
> >
> >
> > On 3/31/2014 1:05 PM, Richard Knoppow wrote:
> >
> >>
> >> ----- Original Message ----- From: "David C. Hallam" <
> dhallam at knology.net
> >> >
> >> To: <boatanchors at mailman.qth.net>
> >> Sent: Monday, March 31, 2014 8:15 AM
> >> Subject: Re: [Boatanchors] HP-8708A Synchronizer?
> >>
> >>
> >>  Ian,
> >>>
> >>> I have a 606B and a synchronizer.  Now that my 606B is working
> properly,
> >>> I will get an idea of how well it works. I had to replace filter
> capacitors
> >>> in the power supply. That was a PITA job as the capacitors are somewhat
> >>> unusual.  The can is insulated and the negative is not connected to the
> >>> can. The ripple was way out of spec and the 606B frequency wouldn't
> >>> stabilize.
> >>>
> >>> I do have a manual for it.
> >>>
> >>> David
> >>> KW4DH
> >>>
> >>>     I've seen isolated filter caps in other equipment such as some
> >> Boonton Radio instruments. They are standard can caps but mounted on
> >> phenolic wafers and have an insulating sleeve of plastic or cardboard
> over
> >> them. In some intstruments the chassis is not at the supply zero
> voltage.
> >> Its been too long since I've been into a 606A or B but -hp- liked to use
> >> regulated supplies where one was used as a reference for the other so
> that
> >> the voltage between them was very constant.
> >>
> >>
> >> --
> >> Richard Knoppow
> >> Los Angeles
> >> WB6KBL
> >> dickburk at ix.netcom.com
> >>
> >>
> > --
> > "I predict future happiness for Americans if they can prevent the
> > government from wasting the labors of the people under the pretense of
> > taking care of them."
> > Thomas Jefferson
> >
> >
> > ---
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