Multimeter Zero woes - UK Vintage Radio Repair and Restoration Discussion Forum

Malcolm T · 9th Apr 2019, 12:54 pm

I have a problem with a very useful multimeter i bought in the mid 1990s .
It wont zero up on two of the Ohms scales.
I have a PP3 Ni-Mh rechargable 9v 250Mah and a AA 3v high energy Lithium inside .
The original connections for two AA batteries were removed a few years ago as the connectors were damaged so i went with a single 3v AA.
The meter will zero on ranges x 10 K and X 1 K.
However it fails to reach zero on X 10 and X1 , all it does here is rises then the needle falls back , is it a lack of capacity in the battery on these ranges

.

The meter is an HT-320.

If i can get my head around picture re-sizing i will post a piccy of the meter.

Any suggestions anyone please.

ajgriff · 9th Apr 2019, 1:53 pm

Classic depleted battery symptoms.

Alan

ionburn · 9th Apr 2019, 2:13 pm

I would agree! Personally I would be wary of using rechargeable batteries in a meter because of self discharge. I checked out my AVO a couple of days back after finding the batteries in my other (Russian) meter were not coping on low ohms range. They were Ok, and have been in it at probably ten years. They both work well enough with original types so personally I keep it original and not invite problems.

GMB · 9th Apr 2019, 2:38 pm

Quote:

I have a PP3 Ni-Mh rechargable 9v

There is no such thing. Rechargeable PP3's are a nightmare area as you will find two quite different kinds. I have encountered 7.2V and 8.4V ones which present as PP3's - the idea is that a freshly charged one might be similar to a flatish real one. Try using a real PP3 and see if it makes a difference.

Likewise a Li cell is a poor approximation to a pair of regular cells.

Malcolm T · 9th Apr 2019, 4:33 pm

Thanks for the help.
I wouldnt put a Li-po in my meter no way.

Heres what i have PP3

https://www.7dayshop.com/products/7d...ck-7day9vgtgx2

Looks like its going to be substituted then for something else !.

Malcolm T · 9th Apr 2019, 4:36 pm

So it looks like they are both going to go then .

Any suggestions to a reliable leak proof batteries without bad internal discharge?.

emeritus · 9th Apr 2019, 5:49 pm

Funnily enough, only an hour ago I thought I had better check the batteries in my own mutimeter, whch uses one PP3 and two AA cells. The AAs are Duracell Ultrapower, well within their 2023 date and not leaking (!), and the PP3 is an Energizer, "Best By" 2013, but still giving full volts and no leaking.

9th Apr 2019, 5:58 pm

For things that have a long term cell/battery insertion time I slaver the compartment with Vaseline. This has saved bits of kit from major corrosion over the years.

Malcolm T · 9th Apr 2019, 6:01 pm

Thanks for the info. I had read the other day about physical and power leakage from batteries and that,s what got me to thinking about this problem , ie curing the fault and maybe the wrong battery types are in the meter.

9th Apr 2019, 12:54 pm	#1
Malcolm T Hexode Join Date: Dec 2018 Location: Lugo, Spain Posts: 483	Multimeter Zero woes I have a problem with a very useful multimeter i bought in the mid 1990s . It wont zero up on two of the Ohms scales. I have a PP3 Ni-Mh rechargable 9v 250Mah and a AA 3v high energy Lithium inside . The original connections for two AA batteries were removed a few years ago as the connectors were damaged so i went with a single 3v AA. The meter will zero on ranges x 10 K and X 1 K. However it fails to reach zero on X 10 and X1 , all it does here is rises then the needle falls back , is it a lack of capacity in the battery on these ranges . The meter is an HT-320. If i can get my head around picture re-sizing i will post a piccy of the meter. Any suggestions anyone please.

9th Apr 2019, 1:53 pm	#2
ajgriff Nonode Join Date: May 2004 Location: Halifax, West Yorkshire, UK. Posts: 2,587	Re: Multimeter Zero woes Classic depleted battery symptoms. Alan

9th Apr 2019, 2:13 pm	#3
ionburn Heptode Join Date: Dec 2014 Location: Lincoln, Lincolnshire, UK. Posts: 583	Re: Multimeter Zero woes I would agree! Personally I would be wary of using rechargeable batteries in a meter because of self discharge. I checked out my AVO a couple of days back after finding the batteries in my other (Russian) meter were not coping on low ohms range. They were Ok, and have been in it at probably ten years. They both work well enough with original types so personally I keep it original and not invite problems.

9th Apr 2019, 4:33 pm	#5
Malcolm T Hexode Join Date: Dec 2018 Location: Lugo, Spain Posts: 483	Re: Multimeter Zero woes Thanks for the help. I wouldnt put a Li-po in my meter no way. Heres what i have PP3 https://www.7dayshop.com/products/7d...ck-7day9vgtgx2 Looks like its going to be substituted then for something else !.

9th Apr 2019, 4:36 pm	#6
Malcolm T Hexode Join Date: Dec 2018 Location: Lugo, Spain Posts: 483	Re: Multimeter Zero woes So it looks like they are both going to go then . Any suggestions to a reliable leak proof batteries without bad internal discharge?.

9th Apr 2019, 5:49 pm	#7
emeritus Dekatron Join Date: Jan 2012 Location: Brentwood, Essex, UK. Posts: 5,349	Re: Multimeter Zero woes Funnily enough, only an hour ago I thought I had better check the batteries in my own mutimeter, whch uses one PP3 and two AA cells. The AAs are Duracell Ultrapower, well within their 2023 date and not leaking (!), and the PP3 is an Energizer, "Best By" 2013, but still giving full volts and no leaking.

9th Apr 2019, 5:58 pm	#8
Guest Guest Posts: n/a	Re: Multimeter Zero woes For things that have a long term cell/battery insertion time I slaver the compartment with Vaseline. This has saved bits of kit from major corrosion over the years.

9th Apr 2019, 6:01 pm	#9
Malcolm T Hexode Join Date: Dec 2018 Location: Lugo, Spain Posts: 483	Re: Multimeter Zero woes Thanks for the info. I had read the other day about physical and power leakage from batteries and that,s what got me to thinking about this problem , ie curing the fault and maybe the wrong battery types are in the meter.