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Calculators: Handheld: Panasonic JE-850U (aka 850)

Size (approx): 98mm x 165mm x 45mm (max) (w,h,d)
Weight 492g including rechargeable batteries but not strap
Power: 6.0V DC, through sealed rechargeable battery pack(JL-032).  It accepts an adaptor/charger (6V DC 1W centre positive, JL-022) through a socket on the right side at the bottom (which is part of the battery pack).  I believe that this model may have come with a similar pack to accept disposable batteries.  An indicator in the far left symbol cluster flags a low battery.
Case: Large two piece white and grey plastic case with a very curved shape.  A raised section at the top contains an oversized neutral display filter that is flush and tilted.  You can just make out the white text for the numeral labels.  The brand and model number is printed in black text in the middle body section.  The oval keys are long travel with a hollow sound like a desktop calculator.  A strong metal tag on the upper left hand side is for the white plastic carry strap.
Display: 8 digit blue VFD, with an additional symbol cluster for negative, overflow and battery indicators. 
Features: 4 function calculator
Age: 1972
Manufacturer: Matsushita Communication Industrial Co., Ltd.  Made in Japan.  Serial number on the inside of the battery compartment is 3402178
Comments: Unique shaped calculator that gets into the handheld category due to the rechargeable batteries rather than its size.  Panasonic did a small range of these shapes (i.e. for the 855 and 860).  This model was also branded as the Olympia CD80 (see Olympia CD81 as an example).  The logic is surprisingly sound for such an early date and only let down by the lack of recovery.

Components: 1 x cpu; Texas TMS0115NC 7239 (week 39 of 1972), 28 pin DIL, 0.6" width black plastic
8 x 1 digit VFD tubes with 1 x symbol cluster tube
36 x transistors
10 x diodes
12 x capacitors
21 x resistors
5 x resistor arrays
1 x transformer; CT-850 TDK
1 x fuse
and on an extra mini-board:
1 x transistor
1 x diode
1 x capacitor
2 x resistors
Boards: The keyboard assembly (Kyoei 31 CF74102A) is attached to the front with 8 screws. It is unusual as each key has its own magnet and reed relay that switches in the proximity of a magnet. The main cpu board (KP-8) connects to this with a 20-way connector.  Built at no expense for easy servicing.  The display, likewise sits on the main board with its own connector.  There is also a min-board with a few components attached to the keyboard assembly.
Construction: There is a screw under the grey label just above the battery compartment.  This, however, does not help a lot.  You need to push the white front section in whilst trying to pop the lugs from any side.  This is very difficult as the case is so thick that there is very little give on the sides.  If in doubt, do not bother as you may damage your example.  Eventually the rear will lift off.

Logic comments: The (CE) button is used to clear last entry of a number and the (C) clear the whole calculator.
Input overflow is suppressed as keying in a ninth digit is ignored
There is automatic constant on all four functions
Negative numbers are shown with a "-" in the far left (ninth) symbol cluster thereby allowing full eight digit negative numbers
Overflow shows the result and "E" in the far left (ninth) symbol cluster and is not recoverable
Divide by zero shows zero and "E" in the far left (ninth) symbol cluster and is not recoverable
A dot lights up in the far left (ninth) symbol cluster when the battery level is low - therefore draining the battery even quicker
No bugs found

This plastic boxed display unit has each separate VFD tube soldered onto a mini-board with edge connector.

The main cpu board is wedge shaped and has two green edge connectors.  The top one if for the display unit above, whilst the bottom one slots into the keyboard assembly.

It has an amazing amount of components crammed into this 79mm by 77mm space.