DE-5000 problem - Page 1
Forum section: electronics / testgear

author: jeffjmr
author_rank: Regular Contributor
timestamp: November 01, 2021, 09:11:35 pm
content: My relatively young DE-5000 has recently failed to measure electrolytic caps over about 1000 microfarad at 1khz. Reads OL. At 100 and 120 hz it reads but I believe the readings are a bit low.Measures smaller caps accurately at all frequencies. Calibrating before measurement passes. Using original TL-21 as well as homemade Kelvin leads, and even plugging directly into the test slots. Battery and AC adapter. No change. My cheap Meterk tests them accurately at it’s fixed 2khz.Any ideas besides “its broke”?Thanks,Jeff

author: TimFox
author_rank: Super Contributor
timestamp: November 01, 2021, 09:21:43 pm
content: Is this a new problem with your unit? If so, what experience did you have with 1000 uF and over before finding this problem?

author: jeffjmr
author_rank: Regular Contributor
timestamp: November 01, 2021, 10:28:53 pm
content: It’s a new problem though it has been some time since I last measured any larger value caps.I did check the output with a scope and the frequencies are right on. I don’t know what signal levels should be or I’d check.Jeff

author: jeffjmr
author_rank: Regular Contributor
timestamp: November 03, 2021, 12:37:05 pm
content: FYIDER replied to an email describing the problem and requesting schematic or repair guide.Response was send in for repair, $120 USD shipping and other fees PLUS cost of repair.Add the DE-5000 to the list of disposable appliances.Jeff

author: commongrounder
author_rank: Frequent Contributor
timestamp: November 03, 2021, 01:02:36 pm
content: Is it possible you might have tested a large value cap that was holding a charge? These units have minimal input protection. I put a big sticker on mine to remind me to discharge caps before testing. It could be a simple damaged component. It might be worth reading through the many threads here about this unit. There’s a lot of discussion of the chips and circuitry used in it.

author: jeffjmr
author_rank: Regular Contributor
timestamp: November 04, 2021, 11:56:06 am
content: It is certainly possible I tested a charged capacitor, but I am careful to discharge. Perhaps I tested one that had been discharged earlier and had recovery voltage.I reviewed posts of teardowns and repairs. I find nothing obvious. Lesson learned. You get what you pay for.

author: armandine2
author_rank: Frequent Contributor
timestamp: November 04, 2021, 12:51:18 pm
content: I didn't think the range extended that far for higher frequencies - but I guess if you have a clear memory of a change in performance it constitutes a failure?

author: TERRA Operative
author_rank: Super Contributor
timestamp: November 04, 2021, 03:36:41 pm
content: Quote from: jeffjmr on November 03, 2021, 12:37:05 pmGeez, $120 is steep, I could head down to Akihabara tomorrow and send you a new one by air mail for that price with change left over.https://akizukidenshi.com/catalog/goods/search.aspx?search=x&keyword=de-5000Someone's padding the price a bit somewhere.......

author: jeffjmr
author_rank: Regular Contributor
timestamp: November 06, 2021, 04:18:03 am
content: Quote from: armandine2 on November 04, 2021, 12:51:18 pmI am aware of that table, though I don’t understand the gaps. I have successfully tested caps up to 3300mfd in the past at 1khz, because it took me a while to get used to the 1khz default at powerup. Now it chokes on 2000mfd, and measures a 1200mfd cap I have at 840mfd at 1khz while my cheap Meterk calls it 1128mfd, and calculated 1236mfd on my oscilloscope.I’ve been pretty careful about discharging, but there certainly could have been some dielectric absorption residual voltage especially on the larger caps. If I get another or can repair this one, I’d probably try the input protection transistor mod referenced in an older thread here.I like the meter when it worked. If anyone has a suggestion where to start looking for DIY repair, I have nothing to lose by trying.The repair quote was, I had to ship it to Taiwan, $80 USD return shipping, $40 USD “Bank Fee” PLUS the repair cost. Of course a new one is available for around $110.

author: commongrounder
author_rank: Frequent Contributor
timestamp: November 06, 2021, 12:55:04 pm
content: Okay, got curious. I pulled out my DR-5000 and 1000uf, 2200uf, and 3300uf electrolytic caps. For comparison, I also fired up my Sencore LC102, And Tektronix DMM4050 meter. On the DR, at 100/120hz, the 1000uf read within a couple of percent of the 102 and 4050. At 1khz, the DR read about 10% low. The 2200uf also read within a couple of percent at 100 and 120hz, but read “OL” at 1khz. Same for the 3300uf. My conclusion is that there is nothing wrong with your unit. Reading electrolytic values at higher frequencies is prone to errors anyway because the inductive component starts to manifest. If you look at data sheets for quality electrolytic caps, you’ll find that they are almost always spec’d for value at 120hz. Of course, ESR is normally measured at higher frequencies, but that is a different matter. Hope that helps.

author: Grandchuck
author_rank: Super Contributor
timestamp: November 06, 2021, 01:42:55 pm
content: Similar results with a U1733C.

author: armandine2
author_rank: Frequent Contributor
timestamp: November 07, 2021, 12:09:04 pm
content: Quote from: jeffjmr on November 06, 2021, 04:18:03 amread across it relates to the range/resolution - if it doesn't have that in the range it gets a dash

author: MaxFrister
author_rank: Regular Contributor
timestamp: November 08, 2021, 12:54:32 am
content: The DE-5000 is not protected from overload (i.e., charged caps). They are easily damaged.I recentlyrepaireda DE-5000 that had become inaccurate. You might check the resistors.I also added some input protection to try to keep it from happening again.https://www.eevblog.com/forum/testgear/der-ee-de-5000-added-input-protection/msg3670312/#msg3670312

author: all_repair
author_rank: Frequent Contributor
timestamp: November 08, 2021, 02:21:20 am
content: Quote from: MaxFrister on November 08, 2021, 12:54:32 amWhich transistor do end up you using? and did you add in the capacitors?

author: jeffjmr
author_rank: Regular Contributor
timestamp: November 08, 2021, 03:51:05 am
content: Quote from: MaxFrister on November 08, 2021, 12:54:32 amThanks, Max.I saw your posts about the protection. I will certainly make that mod if I get it accurate again.Some of the resistors are off in situ, but tough to tell without a schematic. Guess I could pull them and test again.Jeff