[NJARC] Using a LED flashlight to show numbers on tubes

[Thomas Lee]

came across this vid on youtube




http://www.youtube.com/watch?v=MBE6j_qeNp0&feature=g-all-lik&context=G28031b4FAAAAAAAAGAA

Using a LED flashlight to show otherwise invisible numbers of thermionic valves (Tubes) I
 have a 1933 Lissen Skyscraper 3 radio (1933) and I couldn't read the 
numbers on the tubes, even in bright sunlight and using a loop I could 
only just make out part of the numbers on one of the tubes but the 
other tube was totally unreadable. I've found that using a small LED 
flashlight I can easily read numbers that are otherwise invisible. It doesn't
 work in daylight, you need to work in semi darkness for the flashlight to 
work. please let me know if this helps you.