Re: [Amateur-repairs] SETTING UP A TEST BENCH

For the large Dim-bulb user- Amazon.

Gary

On 12/24/2023 10:23 AM, Dan wrote:

My startup rig is a 20A Powerstat variac, re-fused down to an appropriate level, a dim bulb tester, and a Kill-A-Watt meter, then the device under test. Works well. The Kill-A-Watt meter has to be slightly modified to display values at low AC input voltages.    Can you even buy incandescent A19/E26 base incandescent bulbs anymore? Maybe Amazon?    Dan  WB4GRA  

On Dec 24, 2023, at 10:43 AM, Jim Shorney <jimNU0C@gmail.com> wrote:      Another thing worth noting is that makers of variacs often skip putting a fuse on the output side. Think about transformer theory and you will see why this is important.    73    -Jim  NU0C    

On Sun, 24 Dec 2023 09:03:18 -0500  "Tim Reimers KA4LFP" <treimers95@gmail.com> wrote:    "A good rheostat for slowly powering up something that make have been turn  off for the last 20, 30, 40 years."      Couple of points here  A Variac (what you're talking about when you say rheostat)  Does NOT LIMIT CURRENT.  A dead short in a DUT will still destroy components like the DUTs power  transformer, even sometimes at the low voltage a variac provides.    Also, a Variac does not protect you from the AC line. A large (massive)  number of old shortwave radios and other audio gear had "hot chassis"  designs, with no power transformer, and the chassis was physically isolated  from the case.  A so-called AC-AC design.        Best design for a power system for your bench:    Separate GFCI circuit feeding a large isolation transformer, in series with  a Dim Bulb Tester in series with the Variac.    The Dim Bulb Tester does limit current to protect you from those dead  shorted dried out capacitors that will let all the unobtanium smoke out of  your power transformer.    73, Tim KA4LFP            Morse Code: The original digital mode.            

      --    73    -Jim  NU0C