Scored a pair of vintage multimeter twins! - Page 1
Forum section: electronics / testgear

author: reagle
author_rank: Unknown
timestamp: April 11, 2014, 03:00:39 am
content: These must be the smallest DMMs in my collection now:) Does anybody have any history on them?Both seem to be made in Japan, so I am assuming it's just a rebadged Hioki sold as Beckman?Date codes are around 1986, and these things are still alive.

author: retiredcaps
author_rank: Super Contributor
timestamp: April 11, 2014, 07:02:39 am
content: I would love to see a teardown of both when you get a chance.I love doing research on these things. If it says Made in Japan, then the Beckman DM78 is likely Hioki rebadge.https://archive.org/stream/radio_electronics_1987-04/Radio_Electronics_April_1987#page/n29/mode/2upThe model DM78 has 0.7% accuracy: It includes diode test, continuity test, and autoranging capabilities. The meter weighs 3 1 /2 ounces, including the supplied carrying case. It can measure AC or DC voltages over the four ranges of 2-, 20-, 200-, and 450-volts, full scale. Resistance ranges on the model DM78 are 2K, 2QK, 200K, and 2000K, full scale. Bandwidth is specified as 40-500 Hz. There is overload protection to 650-volts DC or peak AC, and the battery life is 70 hours. Test leads are included.The model DM78 is priced at $29.95.— Beckman Industrial Corporation, 630 Puente Street, Brea, CA 92621.There is a html google cached html copy of the pdf manual.http://webcache.googleusercontent.com/search?q=cache:B3NnG5IzReIJ:somemanuals.com/BECKMAN--INDUSTRIAL,DM78,JHJIJCH.PDF+&cd=2&hl=en&ct=clnk&gl=caPS. Modemhead is still dealing with some things and will be MIA for the next foreseeable future, but he has repaired some Beckman DM77s and done the photo documentation for them. The Beckman DM77 is also made in Japan and looks a lot like Dave's beloved Soar meter.

author: Unknown
author_rank: Unknown
timestamp: April 11, 2014, 11:48:44 am
content: I must be getting senile. I could swear I owned one of those Hioki's, and can even remember the wallet that came with it (hinged on the right, meter on the left with a couple of corner straps at the bottom & a strap across just under the display to hold it, a flap to hold the instruction booklet on the right, and the whole thing too small to hold the probes properly) - but I cant remember buying it or ever using it.According to Hiokithey were discontinued in (January?) 1986.

author: N2IXK
author_rank: Frequent Contributor
timestamp: April 11, 2014, 11:59:11 am
content: I keep one of the Beckman units in the glovebox of my truck for emergency use. Runs on a pair of button cells. Got it as a free gift with a purchase from some electronics supplier years ago.Short, permanently attached test leads, and no current ranges. Yes, has the cheap vinyl wallet case. Certainly not a good choice as your only meter, but it comes in handy for simple stuff like testing a battery, finding the hot wire when installing a car stereo, making a quick continuity check on some piece of junque at a hamfest, etc. Wouldn't trust the thing anywhere near mains power, though...

author: rdl
author_rank: Super Contributor
timestamp: April 11, 2014, 05:12:01 pm
content: Separated at birth?

author: reagle
author_rank: Unknown
timestamp: April 13, 2014, 01:37:35 am
content: Definitely a relative! I'll do a teardown of mine once the former owner's tobacco smoke airs out from them

author: madworm
author_rank: Frequent Contributor
timestamp: April 13, 2014, 11:39:49 am
content: Another sibling!I've had this thing "forever", at least 20 years.

author: reagle
author_rank: Unknown
timestamp: April 16, 2014, 03:02:53 am
content: So how many versions did this silly thing exist in?!

author: rdl
author_rank: Super Contributor
timestamp: April 16, 2014, 04:29:28 am
content: The Micronta is obviously not the exact same model as the others. It is similar though, maybe it's a later model. The knob and the display window on the Micronta are centered, on the others they look to be slightly offset. The Micronta's selector knob has the diode check and continuity separated.I opened mine up and there's not much to it. It seemed to be fairly well constructed for what it is. There's 3 screws to remove on the back (one in the battery compartment), and then you can carefully separate (unsnap) the back from everything else. Be careful if you do it because there is some thin metal shielding on the back of the pc board that's also partially glued to the back. The beeper is also glued to the back and the connecting wires are short. Open it like a book to keep from ripping them loose.It appeared that the only thing holding the pc board to the front of the case was the snap ring on the end of the selector shaft, which I didn't bother to remove, so I didn't get a look at the front of the board. The back of the board was pretty plain, basically just ground plane. I couldn't see any identification of the actual manufacturer, though it could have been on the other side. The board itself was decent quality, double-sided FR-4 with solder mask and the soldering (what little I saw) looked to be well done.

author: aargee
author_rank: Frequent Contributor
timestamp: April 16, 2014, 12:07:43 pm
content: Read the thread, went off to check the health of my little, almost forgotten, Hioki - dead.Button-cell-itis - would have been recoverable except the creeping alkaline went up the spring fingers on the switch. I probably left it on by accident.Leaking batteries are the most common killers of my portable test gear, all my less used stuff has the batteries removed until needed.All I can say is.. Check your batteries!

author: staxquad
author_rank: Frequent Contributor
timestamp: April 18, 2014, 04:08:51 am
content: Quote from: reagle on April 16, 2014, 03:02:53 amwhat do you mean silly?been using mine for ages, works as it was intended tohad to open it up to clean the rotary contacts a few years ago and last year had to replace the test leads, they had opened right where they come out of the case

author: GiskardReventlov
author_rank: Frequent Contributor
timestamp: April 18, 2014, 04:18:59 am
content: Quote from: aargee on April 16, 2014, 12:07:43 pmGood advice. I just repaired my old micronta, had I waited much longer it may not have been repairable.(there's another thread on the micronta)

author: sleemanj
author_rank: Super Contributor
timestamp: April 18, 2014, 05:07:57 am
content: I have one of these card type meters in the garage, branded as "Checkman Mini" from memory, but it's too wet and cold to go find it for a photo. Have had it for years, comes in handy for checking voltages and continuity on the vehicles etc.

author: reagle
author_rank: Unknown
timestamp: May 01, 2014, 01:29:24 am
content: My own teardown pictures are finally up at:http://kuzyatech.com/vintage-twins-beckman-dm78-and-hioki-3217Here are the two main boards - it's pretty hard to argue that they are relatedandManuals for both are scanned and posted as well

author: magdyyyy4
author_rank: Newbie
timestamp: June 12, 2016, 09:52:40 pm
content: please i want your help ,by mistake , the 2 components mark with black cyrcle brokeniwant to know what is of each one and mesure to buy its and repair my dm78problem now is buzzer continous make sound as soon as i open v--- or ac.v or diode positions and digital display show false mesure although i did not connect leds with any thing or each other>those 2 components give no any mesure when i test it with another multimetersorry for my bad english