Re: 1502 TDR project - using bench supply

Paul Amaranth

The pack was missing on my 1502 and prices on those are silly (I paid $12 for
the 1502, I wasn't going to pay $50 for a dead battery pack). I made up
a frame out of sheet metal bent like this:

-+ +-
| |

to hold a couple of banana plugs and put in some subC nicads. Then I made
a cover plate that holds it all in. Works fine. I should put a little
slide switch on the cover plate to disconnect the battery when it's in

If you made up a bracket like that, there's probably room to put in a
small 12V power supply with an IEC connector on the back. Then just
swap in the battery when you need portability.


On Thu, Dec 12, 2019 at 11:59:25AM -0500, Mark Pilant wrote:
Hi Tom.

Got around to testing the 1502 using a bench supply. As you suggested,
when hooked up, the 1502 power supply started operating as expected. All
the voltages appeared to be to spec. Although still no trace on the CRT.

I guess there may be some issues with the TekWiki suggested modification
of a 2200uf cap in parallel with a 270 10W resistor.

So now I need to figure out what to do. I'm thinking of possibly using
a 12V 2A "wall wart" supply connected to the banana plugs instead of the
nor mal AC power cord. The main problem is how to actually connect it
all up.

There is room on the rear panel for one of the ubiquitous coaxial power
connectors, but I'm a little reluctant to drill a hole for it. I could
terminate the power card in the supply in a female banana jack attached
to some sort of "paddle" to make it easier to connect / disconnect; but
it would be "a bit" ugly :-)

Any other ideas out there?

- Mark N1VQW

Paul Amaranth, GCIH | Manchester MI, USA
Aurora Group of Michigan, LLC | Security, Systems & Software
paul@... | Unix & Windows

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