[time-nuts] 5370A vs 5370B

[Don Latham]

a schmartcard will let you wire it any way you need, and you don't have to
have a board made.
Don

Demian Martin
> Being naïve I didn't know the HP custom chip would be difficult to
> substitute. Since it was blown and not available I went searching and
> found
> a Maxim chip (MAX9691 I think) that would work on paper. It is surface
> mount
> and I managed to find a header that fit the HP socket and some careful
> wiring from the legs of the chip to the pins on the header got it up and
> running. I'm not sure my eyes are still up to this task. It seems it would
> be a simple task to create the header with chip. I don't know if the 5370B
> would be as easy to substitute.
>               -Demian
>
>
>
>
>
>
> Date: Wed, 10 Mar 2010 00:03:04 +0000
> From: Mark Sims <holrum at hotmail.com>
> Subject: [time-nuts] 5370A vs 5370B
> To: <time-nuts at febo.com>
> Message-ID: <BLU125-W25460FAFB6BA00B5258F2CE330 at phx.gbl>
> Content-Type: text/plain; charset="iso-8859-1"
>
>
> I've had the "pleasure" of fixing way too many 5370A and 5370B front
> panels.
> It's been a while so these musings may be clouded...   also beware of the
> two or three different front panel designs.  Also there are "hybrid"
> 5370A's
> out there with 5370B front ends.
>
> ----------------------------------------------------------------------------
> -----------------------------------
>
> The biggest bugaboo in buying a 5370 is the state of the HP custom input
> amplifier chips.  They can be damaged by overloading the input.   Blow one
> and you are screwed.  Buy a 5370 with a blown input amp and you are
> screwed.
> The 5370A and 5370B used different chips.  The 5345A counter is a source
> of
> input amp chips.
>
> It would be VERY nice if some clever person built  drop in replacement
> "chips" built of modern SMD parts on a DIP header.  Those input amp chips
> are socketed.  They are little more than a comparator.
>
> Quick check of the 5370A inputs is to set the unit to "SEParate" inputs
> and
> connect the back panel 10 MHz ref signal to each of the inputs.  The
> signal
> level LED should flash.  A steady LED means that input is toast (or the
> input PCB slide switches are full of navel lint and need cleaning).
>
>
>
>
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-- 
Dr. Don Latham AJ7LL
Six Mile Systems LLP
17850 Six Mile Road
POB 134
Huson, MT, 59846
VOX 406-626-4304
www.lightningforensics.com
www.sixmilesystems.com