[Boatanchors] HP-8708A Synchronizer?

[Pete Lancashire]

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
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> Thomas Jefferson
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