Pages: 1 [2] 3   Go Down

Author Topic: Analog Multimeter  (Read 821 times)

W1VT

  • Member
  • Posts: 6071
Re: Analog Multimeter
« Reply #15 on: June 24, 2021, 07:02:55 AM »

Most people are better at tuning with an analog meter than a digital display, but I've had great success tuning preamps with the digital display of the HP8970 NF meter.  It may be that I'm pretty good with numbers.

Zak W1VT
Logged

AC9QC

  • Posts: 57
    • HomeURL
Re: Analog Multimeter
« Reply #16 on: June 29, 2021, 11:28:19 AM »

If you're looking for power type diagnostics (e.g. basic electricity in low impedance circuits) it's hard to beat a 260. Yeah they're still $ new but I've picked mine up relatively inexpensively over time used. Worth keeping an eye out for. For high Z circuits stuff a DVM or VTVM is hard to beat. Get one whos form factor is suitable to what you're doing (portable, bench etc.)
Logged

W2EAF

  • Member
  • Posts: 100
Re: Analog Multimeter
« Reply #17 on: July 02, 2021, 04:23:27 PM »

I have a Fluke DMM which I use constantly, but when I need a good old analog meter for doing alignments and measuring RF circuits, I haul out my trusty Heathkit IM-18 VTVM. As others have pointed out it is easier to peak a circuit with a pointer than with digits.
Logged

K3UIM

  • Member
  • Posts: 2145
Re: Analog Multimeter
« Reply #18 on: July 02, 2021, 04:41:39 PM »

cute little digital scopes for under 50 bucks can show ac or dc volts.'
so you have it all. just watch the trace as you would a needle.

i got one for 25$
Where did you find it? eBay?
Charlie
Logged
Charlie. K3UIM
Where you are: I was!
Where I am: You will be!
So be nice to us old fogies!!

W9IQ

  • Member
  • Posts: 8866
Re: Analog Multimeter
« Reply #19 on: July 02, 2021, 05:37:48 PM »

There are a lot of them out there, Charlie. Take a look at this simple kit for $30:



https://www.amazon.com/dp/B07QT81M92/ref=cm_sw_r_cp_awdb_imm_AGMFNA70N7PQXG6M99ZE

It does need a 9 volt supply.

Then scroll down to the "Compare to Similar Items" section to see more choices.

- Glenn W9IQ
« Last Edit: July 02, 2021, 05:45:13 PM by W9IQ »
Logged
- Glenn W9IQ

God runs electromagnetics on Monday, Wednesday and Friday by the wave theory and the devil runs it on Tuesday, Thursday and Saturday by the Quantum theory.

K3UIM

  • Member
  • Posts: 2145
Re: Analog Multimeter
« Reply #20 on: July 02, 2021, 07:43:30 PM »

Thanks, Glenn, it'll be delivered Tuesday. I just hope I'm around long enough to learn how to use it. LOL
Charlie
Logged
Charlie. K3UIM
Where you are: I was!
Where I am: You will be!
So be nice to us old fogies!!

W9IQ

  • Member
  • Posts: 8866
Re: Analog Multimeter
« Reply #21 on: July 03, 2021, 05:14:53 AM »

They are lots of fun packed into a small form. I am sure you will enjoy it.

- Glenn W9IQ
Logged
- Glenn W9IQ

God runs electromagnetics on Monday, Wednesday and Friday by the wave theory and the devil runs it on Tuesday, Thursday and Saturday by the Quantum theory.

K0UA

  • Member
  • Posts: 9589
Re: Analog Multimeter
« Reply #22 on: July 03, 2021, 08:57:02 AM »

Most people are better at tuning with an analog meter than a digital display, but I've had great success tuning preamps with the digital display of the HP8970 NF meter.  It may be that I'm pretty good with numbers.

Zak W1VT

Some peoples organic numeric integrator works better than others.  :)
Logged
73  James K0UA

RADMANCF

  • Member
  • Posts: 16
Re: Analog Multimeter
« Reply #23 on: August 04, 2021, 09:22:52 PM »

So I got myself a Simpson 260 Series 5P off Ebay. For DC voltage measurements it seems to work; haven't tried it for anything else yet. It still had what I suspect was the original Eveready 417 in it. Unfortunatly, one of the contacts for the D battery had snapped off of the end of the wire, but that should be an easy fix. It seems to have been modified at some point; a hole was drilled in the case, and a set of test leads was hardwired to the common and positive terminals. It doesn't look like a hack job, either; there's a nice grommett in the hole. It may need some calibration; it read a fresh D-cell at almost two volts, and a fully charged Milwaukee 18v li-ion battery as 20v, although on the 2.5 volt scale, the d-cell didn't read as high..
Logged

W9WQA

  • Member
  • Posts: 990
Re: Analog Multimeter
« Reply #24 on: August 05, 2021, 05:48:45 AM »

for a wakeup call on 20k meters like simpson do this.
put 2  50 k resistors in series across a 2 v supply.
put meter on 2.5 v range.
read volts on one resistor.
Logged

W9WQA

  • Member
  • Posts: 990
Re: Analog Multimeter
« Reply #25 on: August 05, 2021, 05:54:46 AM »

a cheap little pocket scope like glen  showed here is a much better way of measuring and peaking, 10 meg input
Logged

N7EKU

  • Member
  • Posts: 1471
Re: Analog Multimeter
« Reply #26 on: August 05, 2021, 06:14:27 AM »

I saw 1 meg input on ones similar to the one Glen listed (which I couldn't find a spec on).
Logged
Mark -- N7EKU/VE3

W9WQA

  • Member
  • Posts: 990
Re: Analog Multimeter
« Reply #27 on: August 05, 2021, 06:30:35 AM »

I saw 1 meg input on ones similar to the one Glen listed (which I couldn't find a spec on).
10 meg with probe.
should always use 10 to 1 probe
Logged

KM1H

  • Member
  • Posts: 11155
Re: Analog Multimeter
« Reply #28 on: August 08, 2021, 07:01:54 PM »

I have several 260's as well as Tripplet 630's scattered around radio benches, out in the garage and the shop out back in a trailer.
All were bought used at low cost ::)

The 630 has a 100K resistance position which is excellent for checking leakage on old capacitors, not electrolytics which are the first thing to get tossed when restoring/rejuvenating old tube type boat anchors. indispensable for alignments, locating noisy SMD caps, intermittents, etc.

Carl
Logged

VK6HP

  • Member
  • Posts: 1222
Re: Analog Multimeter
« Reply #29 on: August 29, 2021, 08:51:11 PM »

Earlier, I speculated that my test bench might have room for "just one more" meter, probably in the form of an analog FET VOM.  In the last day or so I was lucky enough to pick up a nicely kept HP410C lab meter (see e.g http://www.barrytech.com/hewlett-packard/meters_analog/hp410c.html), which is in a class well above those I mentioned in the earlier post. I took care to ensure that the meter I was buying had the "new" amplifier board, introduced around 1970 and based on a FET/op amp combination. The earlier board used a devilishly clever low-ish tech chopper based on neons, photocells, transistors and a tube. While it worked well, the choppers are now quite difficult to repair.

The specifications in the link above show that the meter is very capable in terms of accuracy, has a 100 M ohm input impedance on many ranges, and comes with an ac probe which works from a few hertz to over 700 MHz, and from millivolts to hundreds of volts.  To get the sensitivity, frequency response and accuracy HP chose to keep an acorn tube diode in the probe, rather than go to a solid state detector.  The probes can be something of an Achilles heel but, fortunately, mine is in good shape and works well.  If the tube expires and no replacement is available, the probe can be re-built with a solid state diode to give tolerably good results.

The meter was in good condition and, checked against my Keysight 6.5 digit 34461A DMM, was within specification on all dc ranges.  The "ohms infinity" adjustment pre-set was at one extreme of its travel and investigation of the circuit showed a 68 ohm resistor in series with the pot had gone high.  After resistor replacement and pot adjustment the ohms meter was also impressively accurate.  The last fix was to cure a very noisy ac 0.5 V FSD position.  The active probe was clearly working but the meter was very erratic.  After a bit of investigation the lowest range ac calibration pot turned out to be very touchy and the rather specialized 6.5 mm probe socket contacts were a bit the worse for 50 years of use. Some cleaning cured both problems and, after resetting the ac coarse zero and calibrating the low range against the 34461A, the meter was well within low-frequency specifications, with minimal drift.

A quick check of the probe showed an ac response within 1 dB from audio to about 500 MHz, a little down on the original response and accuracy specifications but still very good.  The acorn tubes are still around and, with the rest of the meter working well, I may treat it to a new detector to see if the original specification can be reached.  I was also lucky enough to get the HP11042A coaxial line probe T adapter with the meter, making coaxial in-line measurements easy. So, in the end, a very nice analog electronic meter for not much effort.

A closing question for HP aficionados. Does anyone know if the full manual for the "new" HP410C is available on line?  I have the schematic for the newer A3 solid state amplifier PCB, and most of the remainder of the meter is the same as the earlier version, the manual for which is published widely. Still, it'd be nice to get a full manual for my version and a quick look around the HP Group didn't provide any clues (although a couple of people had asked the same question).

73, Peter
Logged
Pages: 1 [2] 3   Go Up