[time-nuts] 5061A questions

Thu Dec 10 13:47:26 UTC 2009

Morris,

It sounds like you have an earlier 5061A than mine.  Mine has the LED clock
but the battery charger is the same.

Option 03 is a combination of Option 01 (Time Standard) and 02 (Standby
Power Supply).

The NiCad battery is made up of 20 (I think 1/2 D cell) 1.2 V 2300 mAh NiCad
cells.  The charger circuit is somewhat unusual in that it re-charges based
on time of use and not current flow.  The 1/2 D cells at 2500 mAh are
available for about $5 each.  I had a local battery supply house make up a
new pack for mine for right around $100, and it works fine.  I just took him
the old battery which he took apart, removed the old cells, installed new
cells, spot welded tabs between cells, etc.  So, if you still have the
bracket and battery case, you can get it refilled.

I do not know much about the ability to use the charger card with other
batteries.  My limited knowledge suggests that probably not.  I think it
will work ok if the replacement cells are similarly current rated to the
originals.  Mine has done well so far.

You might want to look at the charger card for the 5061B.  It charges based
on current, not time of use, which is a more standard approach.  My
recollection is that the cards are interchangeable.  I am sure others on the
list can be much more helpful on this.

If you decide not to use your battery and charger card, I would be
interested in getting those if you are interested in selling.

I do not know about Option H92 but I suspect that it is a 'remote
monitoring' option.  I have one that has Option H99 that is a remote
monitoring option that has two circular connectors on the back panel in the
bottom right corner as viewed from behind.  There is a board mounted on top
of the A17 board on the bottom of the unit with wires that connect to these
two connectors and the A17 board.  Mine has been nothing but a pain.   I do
not have a schematic of it but I found shorted capacitors and dead
regulators and IC's.  I replaced those, thought I had it working but it is
dead again.  I am hoping to find a schematic to aid in repair but the
ultimate solution may be to remove it.  You might want to look at the A17
board and compare the area in yours with the pictures in the manual.  If you
have an extra board (about 3/4 the length of the A17) on top of your A17
board, I bet it is the 'remote monitoring' option.  I can send you some
pictures of mine if that would help.

I suspect that others on the list are much more knowledgeable on this as
well.

I suspect the lack of a 'door' on top means someone swapped top covers.  You
can probably find one of the correct type.

Good luck with your unit.  They are addicting.

Joe

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Morris Odell
Sent: Thursday, December 10, 2009 5:21 AM
To: time-nuts at febo.com
Subject: [time-nuts] 5061A questions

Hi all,

I recently picked up another 5061A (my second now, I'm becoming a real
Time-Nut :-). The tube seems to be OK, it started up nicely and has been
working well for nearly a week. The Patek Phillipe clock ticks beautifully
in sync with the first one which has a good tube too but runs most of the
time from a Shera GPS controller built into the empty battery compartment.
The time difference between the two has settled down to only a few nS up &
down over the day. Unfortunately the counter I'm using, a 5345A, lacks the
GPIB option so I can't record it.

This one has two mods I'm not familiar with - No 03 and No H92. There's a
red LED labelled "System Alarm" on the front panel between the "Continuous
operation" lamp and the 5 MHz output jack. There's also a DB25 female
connector on the back marked "J30 Alarm". It lacks the little door on the
top cover to allow adjustment of the clock and time offset - very
frustrating.

There was a battery in it, disconnected and well past it's use-by date. The
20 NiCad cells have gone to the recycler.

My questions are:

What are those options?
Can the battery charger be used with cells other than Nicads? 

Nicad cells are getting hard to find but there are plenty of NiMh cells
around and also lead acid batteries. Is it worth setting up a battery? I
have taken out the charger card temporarily. My first 5061A came without the
card so I have no experience of this.

Cheers to all,

Morris

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