I am looking for the following transistor matches. These are the numbers on top line and bottom line of to-92

45-1
427

988
428

45-1
431

78-1
407

 

Maybe 2N series transistors - 2N427, 2N428, 2N431, 2N407, reference available in Google.

 

These may help.
Datasheet catalog for integrated circuits, diodes, triacs, and other semiconductors, view

El-Component Substitution Guide

All Transistors. Datasheet. Cross Reference Search. Transistor Database.

 

Presumably you are attempting to repair a device?
I have found from experience that most times it is not important to get an exact replacement or equivalent.
For a proper substitution you need to know:

1) function of the component in the circuit
2) technology, Ge or Si?
3) operating voltages
4) operating current
5) power dissipation
6) bandwidth
7) package and pinout

 

Those look more like date codes than part numbers. What else is printed on the transistors?

 

The number 2 in a circle, thats it

 

Hello,

Could you post some pictures?
That way we can see the shape and coding of the transistors.

There are many old databooks to be found on bitsavers:
http://bitsavers.org/components/

Bertus

 

The TS already stated TO-92 style transistors, so they are probably silicon, not germanium.
At this point it matters what sort of device the transistors are part of. Is it a radio, tape machine, or part of a toy, as examples. Also the age of the device matters a bit.
OR are they just unused transistors that were in an envelope in a set of drawers purchase at a swap? Those could also be partnumbers for replacements in a scanner receiver, for instance..

 

They may be Zenith or Heathkit part numbers. They often had 2or3 digits hyphen 2or3 digits style to their part numbers to keep customers coming back - many cross reference tables exist.

 

Maybe 2N series transistors - 2N427, 2N428, 2N431, 2N407, reference available in Google.

Those look like Ge part numbers which I've never seen in TO-92 packages.

 

I seem to remember the 2 in a circle was a Sprague marking.

 

They may be Zenith or Heathkit part numbers. They often had 2or3 digits hyphen 2or3 digits style to their part numbers to keep customers coming back - many cross reference tables exist.

Heathkit was notorious for identifying components by their own part numbers. This does make it challenging to duplicate one of their kits without some additional information.

 

Hello,

As @MrSalts stated, there are many cross reference lists available.
I have colled some in this thread:
Cross reference information

Bertus

 

There are also some rather elaborate transistor testers from the 1970's era that will allow you to determine the transistor's characteristics, including polarity, leakage currents, and gain. So if you just need the information to use them that could be helpful.