3 pin TO220 "house numbered" semi's by Texas Instruments" -- help needed

[rodd]

Hi folks,
I am not sure if this is the correct place to post this question but here it goes:
I bought a lot of TO220 parts and while classifying them I came across a lot of "house numbered" 3 pin parts.
I tried to figure out the device type using the Atlas PEAK DCA55 (transistors, FETS, etc) and the SCR100 (SCRs and TRIACs) but unfortunately they showed up as no device connected.
In my experience, the Atlas components testers usually identify 90% of the 3 pin devices I have tried so far.
Any suggestions?
Thanks
Roger

[rodd]

Hi,
thank you for the replies.
These two component testers are capable of identify transistors, FET's and  double diodes.
I have used them in the past with very good results.
They will NOT id voltage regulators, though.
I checked this possibility with a variable DC power supply and a DMM.
If I assume the pinout of a 78xx positive regulator, the output follow the input than drops to zero than goes up again.
When I try the 79XX pinout the input current is very high (probably a forward biased diode).
I could not figure out which 3 pin semiconductor would have this "signature curve".
Ideas?
 

[SeanB]

Have you tried connecting them as LM317, they might be that. Otherwise try the $20 component tester, it generally will show up voltage regulators, or at least use a DMM and diode test for all combinations of pins.