EEVblog Electronics Community Forum
Products => Test Equipment => Topic started by: ealex on July 30, 2013, 09:05:43 am
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Hello
Here are some photos of a "new" HP3466A multimeter:
The date codes on the chips are around 22'th week of 1986.
It was very clean inside and I only had to apply some contact cleaner on the function switches - they were intermittent
Do you know where i can find some end-caps for the range switches ? one of them is missing.
Also, i don't have a clue where to find some appropriate test leads, the standard ones don't fit and making a set from scratch does not seem such a good ideea.
Next step will be to find some sort of reference supply to test it against.
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This meter appears to use standard banana jacks. Most test leads you can buy have banana plugs, but with a safety sheath to prevent accidental contact should the lead get pulled out of the instrument while connected to something. You can usually trim off that sheath, then it becomes a basic banana plug. Obviously this should only be done if you are using the leads with an instrument with jacks like this, and make certain that the plugs fit do snuggly to prevent accidents.
I am curious, why do you say you need a "reference supply" to test this meter? You appear to have a 34401A on your bench. Its precision and accuracy are plenty good enough to verify this instrument (it is 10x as accurate and 100x as precise). Connect any arbitrary but stable voltage to both meters simutaneously and compare. Repeat for all ranges. For ohms, you don't connect simutaneously obviously.
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I'll try to alter some standard probes.
The 34401A is not calibrated - I have no idea if it can be trusted.
I've played around with some batteries and at least the low voltage range seems to work properly.
Maybe it's better to just start using it and testing features as i need them, measuring against the 34401A - it's too much of a hassle getting access to proper equipment.
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If you want some good cheap test leads, I recommend the UNI-T UTL16, http://dx.com/p/utl16-multimeter-test-lead-cable-red-black-2-pcs-150417 (http://dx.com/p/utl16-multimeter-test-lead-cable-red-black-2-pcs-150417) which you can get at about $16...
You can build yourself a very cheap voltage reference (which would be preety stable with temperature, more stable than let's say a battery... of course this can be only for comparative measurements... It's not suitable for this type of application) with the TL431...
Can you take some pictures under the shielded input section ?
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@valentic: sorry, but I will not open it again, it's not very straight forward and I do not want to disturb some sensitive parts if there is no need.
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Push Button Switches (and Caps) used on the HP 3466A.
Schadow Switches (German manufactured) were very popular in 1970s and 1980s.
http://www.wellgainelectronics.com/s...tonswitch.aspx (http://www.wellgainelectronics.com/s...tonswitch.aspx)
Schadow even had an interlocking vision (flag) switch. Schadow became part of ITT.
ITT became C&K Switch.
A common problem with these switches is that the tiny spring (inside the mechanism) breaks.
It can be repaired by replacing that specific spring.
Mouser and Digi Key stock the C&K Switch F-series pushbuttons.
http://www.ck-components.com (http://www.ck-components.com)
Mouser catalog page
http://www.mouser.com/catalog/645/usd/1801.pdf (http://www.mouser.com/catalog/645/usd/1801.pdf)
Digi-Key catalog page
http://www.digikey.com/catalog/en/partgroup/f-series/8826 (http://www.digikey.com/catalog/en/partgroup/f-series/8826)
E-switch discontinued their "clone" versions of these switches a few years ago (TA-series).
Switchcraft has similar DW multi-switch series
http://www.switchcraft.com/Category.aspx?Parent=655 (http://www.switchcraft.com/Category.aspx?Parent=655)
Replacement F-Series buttons (Standard, not custom designs) are available from C&K Switch.
Black, White, Red, and Light Gray are Standard Colors.
http://www.ck-components.com/13342/fpush_31aug10.pdf/ (http://www.ck-components.com/13342/fpush_31aug10.pdf/)
C&K Components
15 Riverdale Avenue
Newton MA 02458
USA
Tel: +1-617.969.3700
http://www.ck-components.com/switches-supplier.html (http://www.ck-components.com/switches-supplier.html)