Mechans, do you mean like this:
http://www.alltubetesters.com/sales.htm
I think it's a foregone conclusion that if you buy a used tube tester, you will have to sink considerable $$ into it to get it working up to snuff. My hickock 533a has been upgraded by Roger (see link), but still likely needs a custom hand wound transformer replacement to acheive accurate voltages on output tubes. I would say it's best to buy a tester that has been thoroughly upgraded by a qualified technician, or this newer computer based model - than to buy a used one that you may have to put 400-1000 dollars into to get it to work properly.
Best, Peter
http://www.alltubetesters.com/sales.htm
I think it's a foregone conclusion that if you buy a used tube tester, you will have to sink considerable $$ into it to get it working up to snuff. My hickock 533a has been upgraded by Roger (see link), but still likely needs a custom hand wound transformer replacement to acheive accurate voltages on output tubes. I would say it's best to buy a tester that has been thoroughly upgraded by a qualified technician, or this newer computer based model - than to buy a used one that you may have to put 400-1000 dollars into to get it to work properly.
Best, Peter