Yokogawa MV200 seems to be defective, no reaction - SOLVED - Page 1
Forum section: electronics / repair

author: Martin72
author_rank: Super Contributor
timestamp: August 20, 2022, 09:34:27 pm
content: Hi,Maybe this could be interesting for other, therefore I report it...Bought a defective Yokogawa MV200 Datarecorder from ebay UK, described as "doing nothing".(Shipping costs and taxes are more than the bidding price, thanks to the brexit..)It arrived, looked "good", I´ve plugged it in to mains and switch it on - Right, nothing happen, no lights, not a thing.OK, let´s check fuses....one fuse and it´s ok.Check voltages....A supply is there, making 12V, measure after switching on, 12V is present - Damn..Only 12V ? Can´t believe it, there must be more supplies there for the CPU and so on and right, little hided, a second supply was there, supplied by the 12V.Hm..If these voltages are also present, something serious must be damaged, maybe the CPU board itself...Connecting the two supplies outside the unit together, switch on....3.3V are there, 5V, 12V, -12V...F**k.All supplies are present, the unit did nothing....OK, this is crap, no more time to waste for.Today I´ve reassembled the unit completely together for making pics for ebay, intend to resell it as defective for spareparts.After finishing this, a last idea came into my mind.I´ve switched it on, everything´s like before, no reaction, no lights on, nothing.But there are no additional lights, no LEDs, only the 10" screen which is dark.Dark...following my last idea I get a pocket light, holding it on the screen by side - BAMMVery weak I could see something on the screen, which was changing when I´ve pressed one of the action buttons.This puppy is alive!!!The backlight is missing!Disassemble it, now looking for the backlight inverterboard(NEC 104 PW161).Looks normal, no blown parts.But there is a fuse on the pcb, a small smd type (1210 I guess), measure it - Yep, it´s blown.Took 2 external psu´s, one for the main 12V, the other for 5V (inverter on/off).Reconnect the backlight bulbs for load ( NEVER turn on a inverter like this without a load), feeding the 12V after the fuse, feeding the 5V as mentioned in the datasheet - Backlight is lit !!So I only have to replace the fuse and then I got a nice data recorder for small money..Now I must find the right fuse type...Pics will follow on sunday.Boy, if I hadn´t got the idea with the pocketlight...Nice thing.Martin

author: alm
author_rank: Super Contributor
timestamp: August 21, 2022, 06:56:43 am
content: Nice work! Thanks for sharing. Sometimes you get lucky with a simple problem, but it's still on you to recognize this. Let's hope the fuse blowing was a random fatigue failure indeed.

author: Martin72
author_rank: Super Contributor
timestamp: August 21, 2022, 09:47:14 am
content: Hi,Hope this too, but got a feeling, this was the only problem.Here some pics from the yokogawa inside and from the inverter, it´s fuse (which seems hard to get)..."As ever" pics are below as I still don´t get it how to place them direct in the post.Martin

author: Martin72
author_rank: Super Contributor
timestamp: August 27, 2022, 01:27:47 pm
content: Argh....Someone else with a MV200 and can take a pic from the inside ?I don´t have any clue where this part below will fit into the machine - But it´s surely from the inside of the yokogawa

author: nctnico
author_rank: Super Contributor
timestamp: August 27, 2022, 01:48:15 pm
content: If you don't have a photographic memory then take pictures during disassembly

author: coromonadalix
author_rank: Super Contributor
timestamp: August 27, 2022, 02:11:08 pm
content: pcb card retainer ??

author: nctnico
author_rank: Super Contributor
timestamp: August 27, 2022, 02:38:13 pm
content: Or something around the AC inlet.

author: Martin72
author_rank: Super Contributor
timestamp: August 27, 2022, 03:37:15 pm
content: Quote from: nctnico on August 27, 2022, 01:48:15 pmHihi....First thought was pcb retainer, but ac inlet...hmm...must have a look.Unfortunately no service manual avaible.Ah, btw, inverter works after fuse replace, pics later.

author: Martin72
author_rank: Super Contributor
timestamp: August 27, 2022, 04:10:09 pm
content: Quote from: nctnico on August 27, 2022, 02:38:13 pmAnd the winner is...nctnico

author: Martin72
author_rank: Super Contributor
timestamp: August 27, 2022, 06:04:44 pm
content: Pics after reassemble...Looks good so far, later on some tests to check all 20 channels.Testing with voltage and temperature, getting some TC-wires from work next week.Unit is from 2006, but without any usb ports - I need a "flash ATA card" for saving datas.If everything is ok, I must make up my mind what to do with it.