On Sat, 13 Dec 2008 17:54:19 -0800, Telamon wrote:

In article ,
Billy Burpelson wrote:

RHF wrote:
On Dec 12, 12:03 pm, Billy Burpelson wrote:
Mike wrote:
Just thought I'd mention a project that I'm a part of. Here, at
the college where I teach, we've purchased several old
Hallicrafter S-38s off of eBay for our beginning Electronic
Engineering students to get some hands-on experience with
communication electronics.
CAUTION! ---- SHOCK HAZARD!!!!!

You may or may not be familiar with the following:

The S-38s are basically 5 tube 'All American Five' radios that do
not have power transformers, but rather have one side of the AC
line tied to the chassis.

To add insult to injury, these radios have a METAL cabinet.

The only thing between the students receiving a severe (or fatal)
electrical shock is the 50 year old (read dry and crumbly) rubber
washers that Hallicrafters used between the chassis and metal
cabinet.

If you've not replaced these washers or put on a polarized line
plug (and checked for correct polarity on the wall socket), you
have a potentially large liability problem on your hands.

Great idea, but bad choice of receiver (IMHO)...

BP - The Voice of Experience Speaks . . . ZAP ! - Ouch That Hurt ;-{
~ RHF

Dave wrote:

I burned a nasty hole in my "Electronics Technology" metal workbench
at PU with an S-38.

Isn't there an "A" variation with a proper transformer?

No. None of the 'S-38' series had transformers. Obviously however,
Hallicrafters had more upscale receivers that DID have transformers.

That might be the best answer. Adding a power transformer if there is
room for one.

A suitable external 1:1 isolation transformer might help.