HPS5 Batteries

Instruments Handheld Oscilloscopes
1

Hi,

My HP5 has developed an interesting fault. It works perfectly with AA alkaline or heavy duty batteries.

However, I decided to use rechargeable NiMH batteries and charged them in an external charger. After fitting them to the HP5 (tight squeeze by the way - they seem to be fatter than ordinary batteries), it doesn’t work. Plugging the power supply in also does not light the LED.

Outside of the HP5 all 5 batteries read around 1.386v on a multimeter.

I’ve done it with 2 sets of batteries, with the same result.

Any suggestion on how to remedy this situation.

Thanks,
Grant

2

Rechargeable batteries have increased in capacity (and size) since the launch of the HPS5 back in 1998.
Due to the latter, it is possible that the battery springs do not touch the batteries when they are inserted.

3

thanks for the tip. That is indeed the problem. I can get 4 batteries in and using some wire and clips connect up the 5th and it comes back to life.

Now to find a way to get the 5th battery in and keep the connection with the battery terminals…

4

found a small strip of metal from a pin carrier and was able to push it between the end of the battery and the contact for the 5th cell.

Then managed to squeeze the battery lid on and put the screw in.

HPS5 now fires up, and battery charge light also.

So as long as the connection stays good and I don’t have to open up the battery compartment again, it should hold…

5

Nice that you’ve managed to make it work.
Keep in mind that the charge current of the HPS5 is 90mA (was OK back in the nineties).
Your batteries will have to charge for ((battery capacity in mAh x 1.2) / 90) hours in order to fully charge them.

6

Hello.
Probably you use < < technical > > batteries, which use for battery pack, because it have short positive terminals for of welding. The short terminals do not concern contacts in holders battery compartment, and unit doesn’t power ON from battery and not charging battery, but unit power ON from adapter OK.
For elimination of a mistake it is necessary to enclose under contacts <<+>> these batteries linings, conducting a current, of the suitable size. Diameters 4-7mm, thickin 2-3mm, also suitable with hole 2-3mm in centre.

7

Found a further problem with my HPS5. The batteries had gone flat, so I charged it overnight. Initially the charge LED came on.

Now I find that the unit won’t power from the batteries, but the battery voltage reads as expected.

It will turn on from the mains adaptor and work fine, but not from the batteries. I am maybe thinking that the switch in the power jack is faulty, but I can’t seem to remove the back cover. I can remove the 2 screws on the back at the top, but the unit seems to be well held at the bottom near the battery compartment, but no obvious sign of screws holding it. Can you advise how to remove the back cover to that I can check the power jack?

Thanks,
Grant

8

“Fixed” the problem. Turned out there were bad connections between the +ve end of the batteries and the metal dimples they were supposed to connect to. Had to pack it with small strips of metal to complete the connection, and it is now working.