WE ARE RICH ELECTRONICS
WE PURCHASE AND RECYCLE
COMPONENTS AND EQUIPMENT!
For sale here we have the above…
High Grade Electrolytic Minican
British Made Vintage Mid 1970’s
Solder Tag Terminals
Red – 4700uF
Plain – Negative
NSN (National Stock Number) 10C 6266075
A NATO Stock Number, or National Stock Number (NSN) as it is known in the US, is a 13-digit numeric code, identifying all the ‘standardized material items of supply’ as they have been recognized by all NATO countries including United States Department of Defense.
They are stored with us still in original NSN packaging, we have tested each one with the following results…
- Capacitance 5904 uF ESR 0.08 Ohm
- Capacitance 5954 uF ESR 0.08 Ohm
- Capacitance 5623 uF ESR 0.10 Ohm
If you have a preference let us know when ordering or any may be sent.
Due to their age they will almost certainly require reforming see below…
Reforming Electrolytic Capacitors
claim that most old electrolytics can be saved if the correct procedure is followed, regardless of how long they have been unused. Such capacitors must be “reformed”. This process consists of applying rated voltage through a resistance (about 30,000 ohms, five watt) for five minutes plus one minute for each month of storage (see figure 6). As the capacitor reforms, the voltage across the resistor will drop (measured at the Xs in Figure 6). If that voltage will not drop below 10% of applied voltage after one hour, the capacitor is probably beyond help.
Reforming Electrolytic Capacitors
The process of reforming an old aluminum electrolytic capacitor consists of the application of rated voltage, through a resistor, for a period equal to five minutes plus one minute per month of storage.
The electrolytics appearing on the surplus market have often been in storage for a very long period indeed. Some manufacturers use a visible code, of which the first two digits indicate the year of manufacture.
The circuit shown in the sketch above works reasonably well. Apply the rated voltage through a 5W resistor. Anything from 20K-50K will do, as this is far from a precision process. The meter is used to measure the voltage drop across the resistor; when no current is flowing, there will be no drop. Obviously, when there is a large voltage drop (more than 20% of the applied voltage), there must be a significant current flow through the capacitor. The nature of a proper capacitor is to impede DC current flow, so when there is such flow, something must be wrong.
Note: Apply the appropriate D.C. voltage to the capacitor with a D.C. power supply. An old Kepco, Lamba etc. tube regulated lab power supply rig works great. Be sure to observe the proper polarity!
NB! This process should only be carried out by qualified engineers etc
Originally supplied to a large ‘Milspec ‘ type Co. these came to us as part of a lot of surplus stock, having been in storage for some years ( packaging dated Oct 1974) we have classified them as ‘new other’.
Length 50mm x 25.5mm Diameter
Lead Length 12mm Width 4mm
These parts came to us as part of a lot of surplus stock from a large ‘Milspec’ type Co. and have been kept in storage for some time, we have therefore classified them as ‘new other’. They are however in pristine condition stored with us still in their original packaging and ‘as new’ in all respects, the photographs are representative of their excellent condition, and, as with all our products they come with a full guarantee.
If you have similar items to this, or indeed any electronic components that are surplus to requirements please contact us with details.