[volt-nuts] Datron 4700 manual and options
pa4tim at gmail.com
Fri Jul 21 07:01:53 EDT 2017
I will order a bunch en 35 or 50V. Replaced them for now with a smaller
value I had. Is only a fixed value LM340 so not very critical. The data
sheet states minimal 2u2 at the input and non at the output
I found the 4707 manual and upto now the schematics are usable. Seems
like I have the AC, ohm and current options. The board I can not find is
the HV option. But I do not mind, I already have 3 calibrators that do
I have a problem in the +/- 400V rails. They are +115 and -38V. I have
no extenders but I use long flexible grabbers. (a wire with banana on
one end and a grabber on the other. Lift the board, clip it to a
testpoint, push the pcb in and measure. Not optimal but workable.
First find out where the 400V is made. Thanks for the help.
On 07/21/2017 01:59 AM, Todd Micallef wrote:
> I used the same values and typically went up to the next higher voltage. I
> think most ended up as 35v since I bought them in quantity. Some people
> recommend the OS-CON family as replacements. Many of the failed tantalums
> fit in a tight space so I just stayed with the original type.
> Once the in-guard was repaired, I found a few other boards where the
> tantalums on the same rail also failed so don't be surprised if more start
> to fail.
> The 4708 service manual is here
> It is now uploaded to KO4BB. The 4808 service manual will be very close
> since the 4708 and 4808 share similar designs.
> The 4708 uses a LTZ1000 as the reference instead of the array of zeners
> used in the 4000 and the lower spec'd 4700. You will have yourself a good
> calibrator once it is brought back into service. Be careful around the
> displays as there is hardly any room between the glass and front panel.
> On Thu, Jul 20, 2017 at 12:55 PM, Fred <pa4tim at gmail.com> wrote:
>> Hi Tod,
>> I just pulled that board (i think) and found a burned 22uF tantalum.
>> Tantalum caps should have a very long life unless used on the wrong place.
>> I guess this is an example. I do not even stock them, the last bad one I
>> had to replace was in a G&M secutest 2 years ago. ( I repair around 10-20
>> Secutests a year and that was the only bad tantalum)
>> With what type/value cap did you replace them ?
>> I found the 4708 manual at KO4BB but that is a user manual without
>> The calibrator should be OK but before I try to start her I always like
>> check things like caps, connectors, solderjoints etc. It really looks like
>> new, not even a scratch or dust. It came with a new looking HP8640 and a
>> new looking HP counter 5248. Both from the same cal lab (part of a company
>> that stayed there) that cal-lab closed about 30 years ago, but all gear
>> stayed where it was (I already had received most of their gear a few years
>> ago). This were the last things because my friend retires.
>> On 07/20/2017 04:51 PM, Todd Micallef wrote:
>>> Shorted tantalums most likely. I had several on mine that went bad as
>>> quickly as I replaced them. I would start with the inguard supply board.
>>> I think the 4708 manual is available for download at KO4BB or xDevs. If
>>> not, I can dig up something. I have a set of the manuals.
>>> On Thu, Jul 20, 2017 at 10:01 Fred <pa4tim at gmail.com> wrote:
>>> Today a friend gave me a Datron 4700. It looks like new. It is stored
>>>> (working) for many years in the cal lab he works. He was allowed to
>>>> take it home (for me, in return I will repair his SA), He plugged it in,
>>>> Fail 1 on the display followed by a sound and a smell.
>>>> I opened it but nothing looks burned.
>>>> I can not find a service manual, does someone has one ?
>>>> On the back the label shows no options but if he remembers it well it
>>>> should have all or at least most options. All slots are filled with
>>>> pcb's. The "box" in the left upper corner is full and there is a very
>>>> small pcb next to it. There is not much room left. Just enough to store
>>>> a small multimeter between the huge transformer and that box.
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