MS5308 died - Page 1
Forum section: electronics / testgear

author: linux-works
author_rank: Super Contributor
timestamp: March 10, 2014, 02:51:56 pm
content: sigh. for a year I have had this lcr meter sitting here. I bought it just over a year and it sat, unused, most of this time (I turned it on just to see the display but never actually got to use it). and of course, I read about the power brick issues and never used the power supply that came with it. I threw it out so that I would not use it by mistakewell, I turned it on yesterday, the display did come on, I pressed the backlight button, that came on, then I pressed the kelvin clip module into the meter's body and by pushing it in, the meter turned itself off. from then on, nothing I could do would bring it back on again ;(I checked the batteries. I removed them and used an HP supply set to 12v to test the circuit. still nothing.I remember a year ago many people had their units die and some even died without the external brick being the blame. has anyone gotton good service from aidetech_us on this? I wrote to him (my seller) and so far, he's telling me to replace the batteries (which I find slightly insulting to send me as 'advice').I'm hoping I don't have a $200 useless door stop on my hands. I will NOT be happy if that's the case. damn, I never got to read a single value from this, either.are there any things I can look at inside to help figure out what went wrong or what blew?I sent a 2nd email to the seller telling him that, yes, I DID replace the batteries and also used a proper lab supply on the red and black wires to the batteries and still I'm getting no display, no sign of life.I'm pretty upset in buying this piece of junk. it looked like a nice bit of kit, but if it does simply by turning it on, I can't quite recommend this unit to anyone, anymore.it will all depend on how the seller handles this. if I'm left high and dry, I'm going to be quite upset about this whole matter.

author: iloveelectronics
author_rank: Frequent Contributor
timestamp: March 10, 2014, 03:15:15 pm
content: I used to sell the MS5308 on this forum and Mastech provided me with some replacement parts (U5 on the PCB) for my customers due to that power supply problem they had. I still have some leftovers (actually only 1 customer blew the part and needed the replacement). As you never used the power adapter I'm not really sure if this would help but if you'd like to try I can send you one for just the shipping cost. Let me know.

author: dfmischler
author_rank: Frequent Contributor
timestamp: March 10, 2014, 03:34:13 pm
content: Does anybody here know if it is essentially the same as thepower circuit in the DER EE DE-5000?

author: linux-works
author_rank: Super Contributor
timestamp: March 10, 2014, 03:48:13 pm
content: iloveelectronics: thanks for the offer! I may take you up on it.I'm not sure where to start, to trouble shoot this. I don't mind doing the work myself, but if it involves removing dense chips using hot-air, I'm not sure I want to tackle that if I don't have to.I had the batteries that came with the unit removed when I put the device in storage for most of the last year. a few months ago, I put the batteries back in, powered it on and it showed a display with no problem. backlight came on no problem, too.I was about to use it to check ESR of some caps I just pulled out of my scope and when I inserted the big plastic pcb-kelvin clip assembly, inserting into the unit caused the display to turn off and never come back on again. maybe something came loose inside? maybe some wire that was nearly shorting actually did short? I know the internal build quality could be better, so I worry that it could be a construction issue or even design issue. maybe even parts quality issue. but I never once got a chance to actually USE it. that's what hurts the most. $200 for a meter and it never once got to be useful for me ;(

author: BravoV
author_rank: Super Contributor
timestamp: March 11, 2014, 02:47:14 am
content: What battery type do you use at that LCR meter ?I remembered that I've read in this forum that a fellow here tested various supply voltage to lower the dissipation on that poor LDO chip while maintaining it's accuracy, but I failed to find it.My MS5308 is using Eneloop NiMh cells since the day one I bought it, and never ever used the external DC power source as at 12 volt is way too high. No, I never use that shitty power adapter that came with it.At average and nominal 1.1 volt per cell, NimH will make that U5 chip much less stressful with lower voltage compared to a fresh alkaline cells.Edit : Of course assuming your problem there is caused by the toasted U5 chip.

author: linux-works
author_rank: Super Contributor
timestamp: March 11, 2014, 04:07:45 am
content: Quote from: BravoV on March 11, 2014, 02:47:14 amthey were original as-shipped AA's. I bought the unit just about a year ago, had it for a few weeks and then had to do a house move, so that went into storage and the batteries were removed. it stayed in storage for most of last year (in boxes) until I got to that box and put the batteries back in. it worked (turned on) and I left them in there. that was a few months ago. then recently, I went to turn it on (still with those factory batteries) and it did turn on. I pressed the backlight and it came on. I then inserted the kelvin probe pcb module and when that went in, the unit turned off. from then on, it would not turn on anymore.QuoteI have not started to research this meter yet. is this a common problem (u5)? I knew not to use the included brick PSU. I never used it since the batteries were fine and I was able to read about the trouble report before I was tempted to even try the brick. so that was fine. I cut the power cord off of it and then threw it away. to make sure I would not go back and use it, forgetting the danger.I was hoping to use this to check the values (not even esr) of the caps I was going to put in my scope and to check the values of the removed parts before I throw them away. now, I can't do any of that (I did the upgrade to my scope but I really wanted to know what I was putting in and taking out).it sucks when your gear fails, but it sucks worse when you have gotton zero use out of it and it dies.

author: BravoV
author_rank: Super Contributor
timestamp: March 11, 2014, 08:02:24 am
content: Quote from: linux-works on March 11, 2014, 04:07:45 amFound it ->https://www.eevblog.com/forum/testgear/ms-5308-power-supply-issues/https://www.eevblog.com/forum/buysellwanted/mastech-ms5308-lcr-tester-member-discount/msg195147/#msg195147

author: mos6502
author_rank: Frequent Contributor
timestamp: March 11, 2014, 10:50:08 am
content: Or, like, get a DE-5000 for ~$120.

author: linux-works
author_rank: Super Contributor
timestamp: March 13, 2014, 03:46:53 pm
content: some encouraging news:I sent an ebay PM to the seller (aidetech_us) and he offered me an RMA that is local, inside the US! (very local, in fact; they have a san jose, CA address).I will take them up on their offer and return the unit to them and see what happens from there. I don't know if there is going to be a charge for this or if they will fix it under warranty but I'll report back on what happens next. at least there's an address to send it to that is not halfway around the world. that's very encouraging, indeed.also, warm thanks to Frankie who offered to help me get this fixed even though I have not been a customer of him (yet!). I will look to try to send some business Frankie's way since I really appreciate the level of service he has offered, to even a non-customer! well done, mate. well done.

author: Fraser
author_rank: Super Contributor
timestamp: March 13, 2014, 07:02:41 pm
content: Having read the story of this unit I would suspect a fault caused by flexing of the PCB as inserting the large 'plug' does require some force. You may just have been unlucky as my unit has been serving me very well indeed.

author: linux-works
author_rank: Super Contributor
timestamp: March 13, 2014, 07:44:47 pm
content: I would agree, that's the only triggerable event I could see. when I pushed the pcb module kelvin thing into the main body and at the point where it inserted fully, that's about the exact time the display went out. it may not have been a regulator or voltage issue at all, but simply flexing the board caused some break of a connection (or a short). still points to shoddy build or design quality. next time, if I can get this fixed, I'll try to leave the pcb module inserted all the time, just to extra-pamper the thing (sigh).

author: BravoV
author_rank: Super Contributor
timestamp: March 14, 2014, 12:41:41 am
content: About the big pluggable pcb module, since MS5308 has two types of kelvin probes, I've been thinking to mod the plug box, and route the cables to external box or mod the plug box directly with a bnc / banana connectors, so no more plug or un-plugging when changing probes.I think I've seen it someone modded it somewhere but forget where ?

author: linux-works
author_rank: Super Contributor
timestamp: March 14, 2014, 01:01:09 am
content: I have not been following this product's threads (until now). has this insertion 'click' been a problem for other people?

author: BravoV
author_rank: Super Contributor
timestamp: March 14, 2014, 01:03:21 am
content: Click ? What click ? Mine doesn't make any sound when the 3 prongs pcb was inserted snugly from the beginning until it plunged fully in it.

author: linux-works
author_rank: Super Contributor
timestamp: March 14, 2014, 01:04:33 am
content: not a locking click, but just the normal sound of the end of the pcb hitting the end of the insert hole.that's all I meant

author: Fraser
author_rank: Super Contributor
timestamp: March 14, 2014, 11:45:06 am
content: Regarding different ways of connecting probes to teh MS5308, readers may be intereested in the attached picture. When I was researching the MS5308 I came across images that definitely showed sockets on the side of the unit for multimeter probes. When my unit arrived it had a blanking plate in place of the probe sockets, so Mastech had decided to not suppply that facility for some reason. It would be relatively easy to retrofit them but from what I can see you would only have 3 connections and not the 6 provided by the plug in modules.

author: linux-works
author_rank: Super Contributor
timestamp: March 25, 2014, 12:13:43 am
content: update: I am happy to say that the seller and mastech both stepped up to the plate and fixed (replaced) the unit for me under warranty (even though I was slightly over the 1 year mark).just got my meter back in the mail and it seems functional. I think its a different unit, so they probably swapped me with another one. I mailed mine back to Calif. but the returned unit came from NJ so it is probably a different unit.aidetek (aidetek_usa is also one of his usernames) helped get me whole again and for that, I have to say a big THANK YOU; and also to mastech to did the actual unit swap.

author: BravoV
author_rank: Super Contributor
timestamp: March 25, 2014, 12:25:08 am
content: Quote from: linux-works on March 25, 2014, 12:13:43 amGlad to hear its solved now !Just curious if there are revisions at this MS5308's board, if there is no warranty seal, if you had a chance, please take a close up shot on the big main board will ya ?