Retro Japanese Powerful flashlight - National BF-769 Bulb + fluorescent

[Kiriakos GR]

New find, old Japanese flashlight. 
Must be technology of 70s.
 
A flashlight with a miniature light bulb and a fluorescent light.
6V
Powered by four D cells.
Alternatively, the Japanese National  (Matsushita Electric Industrial Co., Ltd.) and or as National + Panasonic, it suggests a special rechargeable pack instead.
(Rechargeable Panasonic battery packs (P-14ST) can also be used.) 
Ni-CD ?


National BF-769
Rainproof design
Shoulder carrying strap
National, Fluorescent 4W
National, Incandescent light bulb miniature (krypton bulb) 4.8V 0.5A + spare light bulb.
krypton bulb = long lives, accurate review of color over surfaces ( electric wires )   

Nice yellow bright body, very visible in a emergency
Power switch with three positions,  Bulb - OFF - fluorescent, covered by rubber hood.

I am going to explore all chances, for a conversion to rechargeable, but I will decide after testing it first.
For now, a few stock photographs from Japan they are listed below.   

[Kiriakos GR]

MB-48PF5K = National, Incandescent light bulb / Krypton.

[Kiriakos GR]

Here begins my quick review about National BF-769.

The flashlight its a fully working one.

BF-769 main lens + Incandescent light bulb,  this creates an very narrow beam of light.
At 2-3 meters, beam diameter = only 30 centimeters.
At 5 meters distance, beam diameter = only 60 centimeters

First conclusion, this is a flashlight designed to be a spot light or as long range, and possibly able to cover a perimeter of ten to fifteen meters, at total darkness.

Second conclusion,  Fluorescent 4W this is for use at near perimeter,  its well designed with 90 degrees as coverage.

Both light sources they do create a constant flow of 500mA at 6V DC (its one).

The bad news:  
BF-769  in order to work properly, it must use 4x D Cells.

The batteries are not only used as energy supply, the physical size of the batteries, this creates internally a pressure point, so all metal contacts for electricity distribution, these to make a good contact between them.

Rechargeable  D Cells, they are extremely expensive today.
Most reasonable choice this is the investment of 6€ with VAT,  for two packs of PANASONIC PRO POWER LR20 SIZE D.
https://www.e-shop.gr/mpataria-panasonic-pro-power-lr20-size-d-tem-2-p-ANA.PAN91029

National BF-769 this is originally designed for camping activities.
As spare light source for indoor use, its not that great, due it narrow primary beam.
But the fluorescent light, this will compensate in favor of general use.   
 
Approximate battery life 24H / 25C.

Japanese description:
National BF-769 Flashlight, High-Powered Fluorescent Light, with Shoulder Strap, Retro Design, Battery-Operated, Ideal for Disaster Preparedness, Fishing, and Outdoor Activities.

Battery life:
(Fluorescent lamp) approximately 18 hours continuous use,
(Miniature lamp) approximately 20 hours continuous use
Brightness: (High-power light) approximately 3,000 lx (1 meter forward, rated power)

Weight: Approximately 1.1 kg (including batteries)

[Andrew-88]

These days if this item was still available,  FLUKE Corporation they would have rebranded it as FLUKE flashlight 

I will agree too, that two packs of cheapest D cells, they are enough so this flashlight to keep serving as emergency light source. 

[overvolt]

These days if this item was still available,  FLUKE Corporation they would have rebranded it as FLUKE flashlight 

Very possible ... hahaha   

[Kiriakos GR]

Nice to see smiles and a happy atmosphere. 

I did run some tests at fluorescent section:
Cut off voltage this is as low as 2.5V
Power on voltage must be 3.2V as minimum.

I am now interested to see the actual fluorescent  / power PCB.
And check electronic components health, capacitors etc. 

[Kiriakos GR]

Interesting facts about T5 4W fluorescent Tube Light
Actual working voltage 29V
Actual working current 170 mA

So if the brightness seems not bright enough, first test this is measuring inverter side for the delivery of actual voltage & current.

Brightness = Luminous Flux = 120 or 140 lm, this must be inspected at 1m distance.

Spare T5 4W fluorescent lamp, its not expensive.
The advantage of fluorescent lamp VS LED, this is dim able, brightness it might start fall down as batteries voltage decreases, but you will not stay in the dark suddenly.    
 
https://www.technomat-shop.com/el/products/%CE%BB%CE%B1%CE%BC%CF%80%CE%B1-%CF%86%CE%B8%CE%BF%CF%81%CE%B9%CE%BF%CF%85-4w-%CE%BB%CE%B5%CF%85%CE%BA%CE%B7-%CF%845-15cm-day-light#

[overvolt]

How the PCB looks like ?

[Kiriakos GR]

How the PCB looks like ?

Japanese 

NEC large transistor
Electrolytic 0.5uF
Electrolytic 220uF 10V
All capacitors measure as new. 

Just ordered new batteries.
I did deep clean of the interior and battery contacts.
fluorescent lamp = 80% brightness

[Andrew-88]

Internet search this is dry about this model.

This is a very rare find. 
My impression, this is made at 80s.

Modern Chinese LED flashlight, they have the tendency to FAIL.
They boost LED brightness so these to look attractive, but after few months they become trash.

This thing designed to last, no matter what.