History of Tachikawa (TMK) - Page 1
Forum section: electronics / testgear

author: joeqsmith
author_rank: Super Contributor
timestamp: October 07, 2017, 03:15:00 pm
content: I was given an old Tachikawa meter and had never heard of the brand. So I attempted to do some research on them but found pretty much nothing. This meter was rebranded for IBM and is the 200C. They seem fairly common on eBay and I would doubt are collectible or have much value.This link shows a SN starting with a 6,5 or 9. Obviously they produced a fair number of them.http://www.ebay.com/itm/IBM-Model-200C-Analog-AC-DC-Volt-Ohm-Meter-Read-below-/253158141785?hash=item3af166af59:g:OqYAAOSwpuBZve3BI wrote the IMB archives to see if they had any information about why IBM had the meter built. So far I have not heard anything back from them. A friend of mine wondered if they were not some employee handout sort of thing.Does anyone have any history on TMK or how IBM got tied in with them? I'm sure there is some story there.

author: coppice
author_rank: Super Contributor
timestamp: October 07, 2017, 03:21:01 pm
content: TMK meters were pretty common in the late 60s/early 70s. They were excellent quality, so its not surprising IBM would have used them as a source for their own meters. The one in your picture looks it was designed specifically for IBM, as TMK branded meters generally had 2mm sockets. Your picture seems to show 4mm sockets.

author: joeqsmith
author_rank: Super Contributor
timestamp: October 07, 2017, 04:32:55 pm
content: To be clear, the ad in the ebay link is not mine. Nor am I trying to sell mine. It was only for a reference.From the internet it appears they were also known as:Tachikawa Radio Instrument Co of JapanTachikawa Radio Measurement CoTMK, Tachikawa Radio; MiyataniTMK is the abreviation of Tachikawa Musen Keiki.Musen is the old Japanese word for 'radio'. Keiki is business.I also found a few ads and a schematics. Nothing matched. The one attached is for an AMK-200. Similar, sort of. Like how a cow would compare with a dog.Funny, I don't think of IBM as a hand held meter supplier for the public. This is why I wonder if it was made for their employees. Possibly for their field technicians.

author: joeqsmith
author_rank: Super Contributor
timestamp: October 07, 2017, 04:42:57 pm
content: I had also found this picture showing what appears to be SN# R201356. Note there is no fuse holder and the two additional, unmarked jacks. Maybe IBM told them that a fuse may be a nice thing to add after a few mishaps. I'm sure there's some stories here.

author: coppice
author_rank: Super Contributor
timestamp: October 08, 2017, 12:04:42 am
content: Quote from: joeqsmith on October 07, 2017, 04:32:55 pmMusen is the current word for radio, or more accurately wireless, too. Mu == ? == haven't. Sen == ? == line. Its the same term used in Chinese.Quote from: joeqsmith on October 07, 2017, 04:32:55 pmYou are probably right. They might have been for inclusion in customer toolkits, or something like that, but I don't think they would have been sold as a standalone product.

author: joeqsmith
author_rank: Super Contributor
timestamp: October 08, 2017, 03:01:58 am
content: Here's the IBM branded 200C I have been working on.https://youtu.be/2H6YKvnOQyw

author: SeanB
author_rank: Super Contributor
timestamp: October 08, 2017, 08:27:30 am
content: I have had plenty of AAA NimH cells leak, though generally they only do so with prolonged overcharge. Resistance ranges say the lead and switch resistance is around 2R, and as well you really do need to measure over half scale on resistance, as the accuracy below half scale will be slightly off. AC voltage scales were always different, simply because of the diode drop in the meter measuring circuit, and those with an "output" input had to have a half bridge, often also recycled as the DC meter movement protection, to make sure there would be current flow on both half cycles so the capacitor would not charge up. Also remember the accuracy specs on all ranges were with the meter at close to full deflection, and the error would be roughly the same all through the movement range, being typically 2% plus reading errors without a mirror scale.

author: joeqsmith
author_rank: Super Contributor
timestamp: October 08, 2017, 03:52:03 pm
content: I have yet to see a NiMH leak. I have some in my phones that must be close to ten years old now. The most I saw from one that fail was a small amount of powder (from a phone). Nothing like the damage I've seen with some of the Alkaline's that have leaked on me.As I stated, there were no accuracy specs that I was able to find. Not that it matters.If you looked closely at the check sheet for the meter, the 1.5VDC range was checked it at five different levels. I assume this was done first to verify the linearity. After this, the AC/DC voltages and DC current ranges were all checked at full scale. If you look at the resistance, they ran through all the ranges at 20. Not quite center scale. Again, no accuracy specs but we do know they did not test the meter at full deflection in all modes.If you looked at the schematic, you noticed the separate clamp to protect the meter. I would assume they compensate for the diode drops for the AC mode. Also, there is no capacitor in this meter (not an actual component anyway).

author: SeanB
author_rank: Super Contributor
timestamp: October 08, 2017, 07:11:28 pm
content: I would show you the ones I scrapped this week, but they went to the scrap steel pile, and I am not digging through the drum to find them, way too much sharp stuff in there. Linearity on those meters is entirely dependant on the meter movement, and with the right pole piece design and the right magnetics in there you get pretty much around 0.5% accuracy on most Japanese meter movements, depending on manufacturer, but some cheap ones were only specced to 2%. I have a Hioki meter, which claims 2%, and which uses 1% resistors inside, though almost all the resistors are not E96 values but specific to the meter. Resistance was always going to be the poor side, as you really need a precision voltage source, which an AA cell is not. Better meters ( like light meters as well) used a mercury cell in there, as it has a very flat voltage curve, which gives the error you see as the cell ages, your new AAA cell might be slightly over 1V5, and as it ages it will drop, giving a slight error. In most cases analogue meter resistance readings were good for 5% resistors, any better and you went to another method, like a proper Wheatstone bridge, which was not dependant on the battery voltage, but only needed accurate resistor ratios to be accurate.

author: joeqsmith
author_rank: Super Contributor
timestamp: October 08, 2017, 09:00:31 pm
content: To be clear, I was not asking to see your leaking cells. If you damaged several from over charging them and fail to learn not to do that, I really have nothing to learn from seeing the end result. I use a proper charger and can only tell you that I have yet to see a problem with them. Maybe there is a lesson one of us could learn from?I really have not used an analog meter in many years. Since my youth. If I had a top of the line one sitting here, it would get used as much as an analog scope. When I was using one, I would guess 10% for my amature skills was more than enough.

author: joeqsmith
author_rank: Super Contributor
timestamp: October 12, 2017, 12:16:37 am
content: The new Panasonic batteries came in today. I had this meter all apart and the nut for the selector switch was originally held in place with some off white paint. So I touched that up and painted the tops of my custom sleeves. The batteries are worth more than the meter.I spoke with my wife's brother who had found the meter. He was surprised I tried to restore it. As I understand it, it was found in the basement of an abandoned home. The home was starting to collapse and this is why they were brought in to demo it. They will normally do a walk thru to check for any hazards and this is when he saw the meter in the basement. The women who owned the home had passed away in her 90's. She had never been married and never held a technical position. How she ended up with the meter is a mystery.I never heard anything from the IBM archives, so I am at a dead end.The solder work you see is for the most part original. I was trying to preserve the meter as much as possible. I didn't mention it in the video but to repair the corner, I used some mylar tape that I basically formed a dam around the inside and outside of the case, after I had prep'ed the plastic. I then filled this with epoxy and let it set. Once the tape was removed, I had the basic shape. Lots of sanding and buffing after that. I had looked for some old plastic and was going to make a powder to blend in with the epoxy to help color it. I could not find anything laying around to salvage so I just used three different colored markers to get it somewhat close.

author: joeqsmith
author_rank: Super Contributor
timestamp: October 14, 2017, 03:57:41 pm
content: I received a response back from the IBM archives and sadly they had no information on this meter. They copied their curator. I provided them with a link to the video.The white Panasonic batteries look alright with the white sleeves.

author: SeanB
author_rank: Super Contributor
timestamp: October 15, 2017, 04:49:16 pm
content: Not my charger, but the ones built into Siemens Gigaset cordless phones, All of them from the earliest version ( at least from 1990 when we started using some variants of them) do not have good charge termination, and will charge the cells continuously. While a NiCd cell will be quite happy with this charge NimH cells tend to generate overpressure and fail after a year or so, so for those phones that are placed every night to charge they kill the cells in around 9 months, and I have to buy a new set of them. Makes no difference as to what cells I put in, even the original ones die in that time, and I just keep my phone off the charger all the time, placing it on for around an hour every 3 days or so to charge.Other than that they are somewhat reasonable cordless phones, though I do really miss the old Panasonic KX-P9080 I used to use, even with all the issues it had with really poor flip design, it at least had a 1km range. I kept it going thanks to having a good supply of water and other damaged KX-P 9001 phones to rob case parts, speakers and microphones from, though I gave up eventually on the flap and put in a small switch to act as hook switch, along with making my own antennas for it out of old bits of coax cable. Eventually ran out of spares and RF modules for it though, though the 4 AA cells in the batteries were easy to repack, I just put in high capacity cells, and that rarely gave trouble.

author: joeqsmith
author_rank: Super Contributor
timestamp: October 15, 2017, 05:41:08 pm
content: 2017 to 1990 would be 26 years or 324 month or 36 sets of batteries. At some point, it would seem ditching the phone would make sense. Even ditching the OEM charger, buying a separate charger and rotate batteries may have been more cost effective.Last Friday, I installed new NiMH batteries in the neighbors cordless phones. Three handsets with 3 AAA batteries ea. The old ones are marked Panasonic but made in China. There are no date codes from what I could tell but I expect the phone was well over 5 years old and there are no signs of any leaks.I still use my old Olympus Camedia BA-100 charger along with the original batteries. These have a date code of 00-11. Maybe Nov of 2000. It would be close to the age of the camera. Like the ones I use now, they reached a point where they would not hold a charge but 17 years without a leak seems pretty good. That's a pretty low end charger.

author: joeqsmith
author_rank: Super Contributor
timestamp: October 16, 2017, 04:43:46 pm
content: Quote from: joeqsmith on October 14, 2017, 03:57:41 pmI received an email from the Curator Of IBM ArtifactsQuoteAt least it tells us that IBM did supply meters to their service departments and our little meter may have been built for internal use but how this particular one ended up in the basement of an unmarried lady who did not work in tech, we may never know.

author: Bud
author_rank: Super Contributor
timestamp: October 16, 2017, 05:02:32 pm
content: I wonder what office products IBM was making in 1966...maybe that could give someclues.

author: fanOfeeDIY
author_rank: Unknown
timestamp: October 20, 2017, 09:46:48 am
content: I have the meter!What a consistence.My father used to be an IBM Japan employee started as a type writer engineer, since he was mechanical engineer.The company grew in electronic and computer industries, while he was keep being a mechanical engineer.Already retired long time ago.The 200C analog multimeter was in his type writer service case with other tools like screw drivers and etc.And I borrowed it when I was in high school from his service bagand still keeping it.The multimeter seems to be slight different revision since it uses regular AAA battery.The solder joints are still very good and I uses this meter for battery checker some time,because analog meter draws current and it is easier to hunch the battery lifeby watching the speed of needle movements.I attached the pictures of mine.This was *the* first multi-meter for me and I really took good care of it until today.The leather case and leads are genuine. I could assure that.

author: fanOfeeDIY
author_rank: Unknown
timestamp: October 20, 2017, 09:50:24 am
content: Quote from: blueskull on October 08, 2017, 04:22:58 amblueskull is right. The word of "keiki" used for any equipment looks mechanical and have a meter.

author: joeqsmith
author_rank: Super Contributor
timestamp: October 21, 2017, 06:04:47 pm
content: Quote from: fanOfeeDIY on October 20, 2017, 09:46:48 amThanks for the response. Looks like the serial number is 7129031. Would seem to be a newer meter than the one I was given. It would make sense that if they were having troubles with US batteries, they may have changed the case dimensions.What I find VERY interesting with your dads old meter is that the resistor circled on yours is attached to the meter (-). If you look at mine, you will see it also attached to this same location but has some black sleeve over it. This resistor used to go to the fuse holder but I added the sleeve and changed how it was wired.On your meter, when you remove the fuse, can the meter read both current andvoltageresistance? I wonder if they actually changed the design like I show in later serial numbers.Wrong mode. Actually, it would be good to how the fuse effects all of the modes on your dads.

author: joeqsmith
author_rank: Super Contributor
timestamp: October 22, 2017, 01:41:35 am
content: Quote from: Bud on October 16, 2017, 05:02:32 pmThe Selectric typewriters?

author: Bud
author_rank: Super Contributor
timestamp: October 22, 2017, 04:38:17 am
content: Ok so how about a story with a IBM office products repair technician coming to the lady's house to fix her typewryter, then forgetting the meter there as he leaves the house.

author: joeqsmith
author_rank: Super Contributor
timestamp: October 22, 2017, 04:39:31 pm
content: I'm sure you could make up all sorts of stories. I doubt an IBM service person would make a house call to repair a personal typewriter. It would make more sense they would send the typewrite to a repair shop.I was able to find out a little more about the lady who owned the home where this meter was found. She apparently owned several properties in the area and would rent them out. I also understand she was a hoarder. It would make sense that the meter was owned by someone renting from her and it was left behind where she added it to her collection. That's the story I am going with anyway.

author: fanOfeeDIY
author_rank: Unknown
timestamp: November 07, 2017, 11:35:00 am
content: Quote from: joeqsmith on October 21, 2017, 06:04:47 pmSorry for the late response. I was busy with my hobby project making a flight controller of a drone.I tried removing the fuse from my meter and I was able to measure voltage and current but not the resistance.And I searched for the size of AA battery standard in Japan (it is called JIS) and found that the minimum length was 49mm and maximum was 50.5mm, so some batteries were only targeting 49mm. The 1.5mm difference is a lot for only 50mm battery.I heard that now all are 50.5mm in Japan.And this seemed to cause some batteries do not fit in the battery case.

author: fanOfeeDIY
author_rank: Unknown
timestamp: November 07, 2017, 11:55:51 am
content: Hi,Another point that I found today when I was testing the meter, the accuracy for the resistance and voltage were very good but not so well on the current range any more.Well it must be made in 70' and notAnd the leads I have is probably not the original one. It looks like I made them more than 30 years ago with 2mm banana jack with slim pvc cable with alligator clips.I think I wanted to have the alligator clip to my meter.

author: joeqsmith
author_rank: Super Contributor
timestamp: November 07, 2017, 01:31:13 pm
content: Thank you for taking the time to check. I would have bet on it protecting the current input. It's strange how they would change how it was wired but maintain the same functionality. I wonder if this change was a labor savings.I saw another one that was also newer than mine. On mine, there is a white plastic part that bolts in behind the clear lens for the movement. On this meter, they were no longer making this plastic part but instead using paint. I assume this was for cost as well.I suspect that the alligator clips on mine are also not original. The banana connectors and wire appear correct. Everyone I have seen for sale appear to have the leads altered.This one showed up with an older SN but the leads appear to be newer.https://www.ebay.com/itm/Vintage-Tachikawa-Model-200C-IBM-Voltage-Ohm-Meter-Works-great/322866105225?hash=item4b2c51cb89:g:e1IAAOSwPAxZ~4GV

author: fanOfeeDIY
author_rank: Unknown
timestamp: November 08, 2017, 11:32:26 am
content: Quote from: joeqsmith on November 07, 2017, 01:31:13 pmWas or is your meter behaving differently when it does not have the fuse?I am not completely understanding how the rotary switch work on the schematic (model AMK-200, you have posted on this thread), however the fuse seems to work for voltage and current but not for resistance.https://www.eevblog.com/forum/testgear/history-of-tachikawa-(tmk)/msg1318383/#msg1318383I just would like to know about this meter and your knowledge of surge protection knowledge on your youtube videos.

author: mzacharias
author_rank: Frequent Contributor
timestamp: November 08, 2017, 01:46:53 pm
content: I constantly peruse eBay for mutimeters. I have seen many variations on the theme of this IBM model. Lafayette had quite a few, Radio Shack even had one or two, maybe even Eico / TruVom (spelling?) I believe the OEM companies like TMK and Kamoden had agreements with Lafayette, Radio Shack, et al prohibiting them from directly competing in the U.S. market. This I believe is why you rarely see Kamoden or TMK branded VOM's in the U.S. but see many of their products from Radio Shack, Mura, and others.

author: coppice
author_rank: Super Contributor
timestamp: November 08, 2017, 01:55:21 pm
content: Quote from: mzacharias on November 08, 2017, 01:46:53 pmWas Lafayette a brand name of Radio Shack/Tandy? I remember seeing some TMK meters in the UK branded as Lafayette after Tandy starting opening shops there.

author: joeqsmith
author_rank: Super Contributor
timestamp: November 08, 2017, 02:10:24 pm
content: Quote from: fanOfeeDIY on November 08, 2017, 11:32:26 amMine originally worked like your dad's. The fuse only protected the resistance measurement. I changed the design to protect both the resistance and current measurements. The voltage still works without the fuse. The only reason I made this change was if I decide to use the meter in some future video for current, I wanted the added protection.Quote from: fanOfeeDIY on November 08, 2017, 11:32:26 amIn that schematic, the fuse is in-line with everything. I am not sure how much protection it would really provide (for the meter) but it's better than nothing. I don't like meters that will not display the voltage with a blown fuse.In the attached, I have marked the path for the 250mA setting.Quote from: fanOfeeDIY on November 08, 2017, 11:32:26 amThose few videos where I modified the Kasuntest ZT102 and the UNI-T UT61E were my attempts at explaining it. From what I have seen most of the meters, well the ones that actually survive to some decent levels anyway, basically take the same approach to hardening the front end.

author: fanOfeeDIY
author_rank: Unknown
timestamp: November 12, 2017, 01:20:00 pm
content: Quote from: joeqsmith on November 08, 2017, 02:10:24 pmI see, even I did not change the internal wiring, and it was different from yours, the fuse on my meter (or dad's) was only for resistant and the fuse was not protecting the voltage and current.I have an other analog meter made by Sanwa, and when I removed the fuse, all voltage, current and resistance stopped working.Different analog meters seem to have different approach.Looking forward for your future video.

author: fanOfeeDIY
author_rank: Unknown
timestamp: November 12, 2017, 01:25:53 pm
content: Quote from: joeqsmith on November 08, 2017, 02:10:24 pmThank you for detail diagram with marking. I completely understand how the rotary switch would be written in the schematics now.I was playing with this meter and I realized that it is nice to be able to use the own meter for battery checking and the fuse, and this analog tester is able to do it.

author: Tepe
author_rank: Frequent Contributor
timestamp: November 12, 2017, 02:32:55 pm
content: The insides of my TMK model 200:The outside and original box:(Edited to add picture of the outside of the meter)

author: joeqsmith
author_rank: Super Contributor
timestamp: November 12, 2017, 05:59:43 pm
content: The closest schematic I found to my 200C was for the TP-5SN. I used it as a starting point. Keep in mind, there may be mistakes.Quote from: Tepe on November 12, 2017, 02:32:55 pmVery nice. I had wondered if these had a fuse in them or not.

author: Tepe
author_rank: Frequent Contributor
timestamp: November 12, 2017, 06:28:18 pm
content: Quote from: joeqsmith on November 12, 2017, 05:59:43 pmHere's a photo of the schematics part of the model 200 instructions.As it says, it came with a spare fuse. The tape residue seen in the picture of the insides, is where the spare was placed

author: joeqsmith
author_rank: Super Contributor
timestamp: November 12, 2017, 08:35:45 pm
content: Thanks for taking the time to provide that picture. There is very little written information I can find on the net about these meters and every little bit helps.It's interesting that your meter has the fuse in series with the common to provide some protecting in every function. It must have been around the time that they started thinking that they may not want disable the voltage measurements. Then again, I have seen a few modern meters that do this same thing.

author: Tepe
author_rank: Frequent Contributor
timestamp: November 12, 2017, 10:05:57 pm
content: Quote from: joeqsmith on November 12, 2017, 08:35:45 pmMy warranty card states that the importer tested the instrument November 12, 1979. I guess it is reasonable to assume that it isn't a lot older than that.

author: timb
author_rank: Super Contributor
timestamp: November 13, 2017, 02:37:56 pm
content: Quote from: joeqsmith on October 22, 2017, 04:39:31 pmActually, individuals could get a service contracts through IBM. If your Selectric broke, a repair tech would come out and fix it. They were very complex machines, mechanically and required specialized adjustments if certain parts were replaced.IBM already had a nationwide network of repair techs in place, after all, what company wants to send each typewriter to a repair shop. So it makes sense they’d offer the contract to individuals and small businesses as well. A service contract was about $100, which wasn’t bad considering a Selectric could cost over $1000!

author: coppice
author_rank: Super Contributor
timestamp: November 13, 2017, 02:50:29 pm
content: Quote from: timb on November 13, 2017, 02:37:56 pmThe service contract for most IBM equipment worked out remarkably close to 10% of the purchase price in those days.

author: fanOfeeDIY
author_rank: Unknown
timestamp: November 14, 2017, 05:30:50 am
content: Quote from: Tepe on November 12, 2017, 02:32:55 pmJust nice! With original box.

author: DF1DA
author_rank: Newbie
timestamp: September 15, 2022, 06:06:29 am
content: Hello Tepe,thanks for the pictures. The photo of the instruction leaflet with schematics are very helpful. Reason:It happened to me to find such an instrument at a second hand store during holiday in Denmark for just 20DKR. Comparing it with yours it might be an early version w/o the fuse on the common input, without protection diodes across the meter and with different labels on the inputs. Luckily the AA cells did not (yet) leak, of course now replaced by new ones.Gerhard

author: langlv
author_rank: Contributor
timestamp: January 22, 2023, 10:29:48 am
content: Hello joeqsmith,I got a TMK 100K, with design very similar to Simpson 269. I found a schematic on another forum, but in my VOM there is an additional relay (for overload protection?).Hope you have some info abit it.Best, and Happy New Lunar YearLang

author: joeqsmith
author_rank: Super Contributor
timestamp: January 22, 2023, 06:20:12 pm
content: I don't see a relay in the schematic you linked. Maybe you could trace that section out and post it. We may be able to sort out its purpose from that. I found a link showing a few pictures of the meter and talking about the 269.https://www.vintage-radio.net/forum/showthread.php?p=746757

author: langlv
author_rank: Contributor
timestamp: January 23, 2023, 04:37:20 pm
content: Finally, it's not an overload protection, but a buzzer for continuity test.The buzzer is not in part list, and is drawn as very discret circle in the schematic.To achieve 10uA FS, the coil is quite large, almost 1 inch. I guess they did not make enough strong magnet. It's incredible that Triplett managed to build a 1uA FS with a smaller coil.

author: joeqsmith
author_rank: Super Contributor
timestamp: January 23, 2023, 06:34:21 pm
content: Funny to see the chain drive. Looks like a gear split. I wonder if you could have a set made from brass.

author: coppice
author_rank: Super Contributor
timestamp: January 24, 2023, 02:33:45 pm
content: I used to own a TMK 100k. I don't know where it went. It was an excellent instrument. The only weakness was the handle mounting. The bolts holding it could work undone, until you applied something to stop them. That chain drive approach allowed for a really nice layout inside, although like most multimeters of the time it must have taken someone quite a while to build it. I liked the way they tuned the 10A shunt.It does have a buzzer for continuity, and it does not have overload protection. It has a nice wide resistance measurement range, but this requires a 15V battery which is probably hard to find these days. The use of a large 1.5V D cell for the lower resistance ranges kept the battery life high when using that buzzer a lot.Being so sensitive, but with a really long pointer, you really need to use the meter damping "off" position when moving the meter, or it might prove a bit fragile.

author: bonallesan
author_rank: Newbie
timestamp: November 08, 2024, 06:41:31 pm
content: Hello from Ukraine. I don't speak English, so I use Google Translate. please help to find the diagram of this station. This device needs repair. Thank you. for attention