Beckman Industrial HD110 Multimeter - UK Vintage Radio Repair and Restoration Discussion Forum

ScottBouch · 5th Jun 2023, 10:56 pm

Hi all,

I have an HD110 Multimeter (Stores ref: 10S/7819640). It used to work, but it's been at the back of a cupboard for a number of years.

I have found it today and had a little go, sadly the display to is now a bit of a "random number generator".

In AC V, it reads roughly 030, when changing range, the decimal point moves, but he figures stay the same, ie, could be 3 mV, 300 mV, or 3 V. It actually flicks around a bit.

On DC, its similar, but some ranges are negative, some positive..

Some LCD segments don't always appear either, will come and go with the flicking around.

Similar performance on current and resistance ranges too, leading me to think there must be a common issue to the display side of things.

Any thoughts, manual or circuit diagram would be appreciated! Be nice if it's just a cruddy connection between boards or something similar.

Many thanks, Scott.

chriswood1900 · 6th Jun 2023, 12:18 pm

Scott
I think this DMM uses a zebra strip to connect the display to the motherboard a good start would be to remove the display and give a it good clean with Isopropyl Alcohol. If that does not work it might be worth cleaning both the switch contacts and the processor connections.
Good luck

Dickie · 6th Jun 2023, 10:01 pm

This might help. Mine went the same way and I ended up binning it.

factory · 8th Jun 2023, 6:41 pm

I didn't realise these used an unusual IC for the main DMM chip and zebra strips for that too, cleaning seems to be the recommended repair for the random digit problem.
http://mrmodemhead.com/blog/beckman-...10-multimeter/

Most at work seemed to fail due to the case plastics disintegrating with age, I used a Beckman 350 for many years.
In my collection I have a Tech310 and one of it's modern descendants, the Wavetek HP160B, both have the 1500Vdc range.

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David

ScottBouch · 13th Jun 2023, 9:19 am

Thank you for the circuit diagram and advice both.

I will take a deeper look at cleaning up contacts etc and see if it helps.

Ref casing, the metal threaded 'inserts' that the case screws screw into are mounted in plastic 'bosses' that had fractured. All glued back together now.

duncanlowe · 13th Jun 2023, 9:32 pm

I too had one many years ago. Same problems: display failed, assumed zebra strip. Tried to dissasemble and the plastics just fell apart. I assumed I just had left it in a box with something exuding solvents. Seems it was just something that happened.

5th Jun 2023, 10:56 pm	#1
ScottBouch Octode Join Date: Feb 2013 Location: Leicestershire, UK. Posts: 1,074	Beckman Industrial HD110 Multimeter Hi all, I have an HD110 Multimeter (Stores ref: 10S/7819640). It used to work, but it's been at the back of a cupboard for a number of years. I have found it today and had a little go, sadly the display to is now a bit of a "random number generator". In AC V, it reads roughly 030, when changing range, the decimal point moves, but he figures stay the same, ie, could be 3 mV, 300 mV, or 3 V. It actually flicks around a bit. On DC, its similar, but some ranges are negative, some positive.. Some LCD segments don't always appear either, will come and go with the flicking around. Similar performance on current and resistance ranges too, leading me to think there must be a common issue to the display side of things. Any thoughts, manual or circuit diagram would be appreciated! Be nice if it's just a cruddy connection between boards or something similar. Many thanks, Scott. __________________ www.scottbouch.com

6th Jun 2023, 12:18 pm	#2
chriswood1900 Octode Join Date: Jan 2007 Location: Dorridge, West Midlands, UK. Posts: 1,486	Re: Beckman Industrial HD110 Multimeter Scott I think this DMM uses a zebra strip to connect the display to the motherboard a good start would be to remove the display and give a it good clean with Isopropyl Alcohol. If that does not work it might be worth cleaning both the switch contacts and the processor connections. Good luck __________________ Chris Wood BVWS Member

8th Jun 2023, 6:41 pm	#4
factory Octode Join Date: Jul 2009 Location: Cheshire, UK. Posts: 1,738	Re: Beckman Industrial HD110 Multimeter I didn't realise these used an unusual IC for the main DMM chip and zebra strips for that too, cleaning seems to be the recommended repair for the random digit problem. http://mrmodemhead.com/blog/beckman-...10-multimeter/ Most at work seemed to fail due to the case plastics disintegrating with age, I used a Beckman 350 for many years. In my collection I have a Tech310 and one of it's modern descendants, the Wavetek HP160B, both have the 1500Vdc range. David Last edited by factory; 8th Jun 2023 at 6:46 pm.

13th Jun 2023, 9:19 am	#5
ScottBouch Octode Join Date: Feb 2013 Location: Leicestershire, UK. Posts: 1,074	Re: Beckman Industrial HD110 Multimeter Thank you for the circuit diagram and advice both. I will take a deeper look at cleaning up contacts etc and see if it helps. Ref casing, the metal threaded 'inserts' that the case screws screw into are mounted in plastic 'bosses' that had fractured. All glued back together now. __________________ www.scottbouch.com

13th Jun 2023, 9:32 pm	#6
duncanlowe Nonode Join Date: Jan 2016 Location: Stafford, Staffs. UK. Posts: 2,532	Re: Beckman Industrial HD110 Multimeter I too had one many years ago. Same problems: display failed, assumed zebra strip. Tried to dissasemble and the plastics just fell apart. I assumed I just had left it in a box with something exuding solvents. Seems it was just something that happened.