Geekcreit D1 Mini Pro from Banggood, fake Wemos with 150mA 3.3V regulator - Page 1
Forum section: electronics / general

author: chevybeef
author_rank: Contributor
timestamp: July 04, 2020, 11:15:24 am
content: Bought one of these here:https://www.banggood.com/Geekcreit-D1-Mini-Pro-16-Module-ESP8266-Series-WiFi-Wireless-Antenna-p-1144951.html?rmmds=myorder&cur_warehouse=UKwhich turned out not to work properly. WiFi struggled to connect, didn't connect, or disconnected soon after connecting.Jumped on Google only to discover it's a fake:https://www.reddit.com/r/esp8266/comments/9iizx4/warning_clone_wemos_d1_minis_with_only_150ma_33v/Tried customer support only to be given the run around asking for photos, videos etc, what I sent was't enough for them so I tried disputing via PayPal. Banggood agreed to refund but only after returning item to China by 13 July, I bought it from the UK warehouse. That's a pretty tight deadline and even so, shipping to China would cost almost as much as I paid and there's no guarantee it gets there in time or even gets there at all. Plus they want it in as received condition which is impossible because to test it I had to remove it from the packaging and solder the headers on.Two great lessons learned for £7.93: Banggood can't be trusted and PayPal don't have the customer's back.As an electronics person it's going to be hard to avoid goods from China, if not impossible?

author: AVGresponding
author_rank: Super Contributor
timestamp: July 04, 2020, 01:57:59 pm
content: If you bought it from a UK warehouse, you're covered by UK consumer law.Don't take no for an answer, demand a refund, threaten them with Trading Standards, small claims court, w/e it takes.

author: ledtester
author_rank: Super Contributor
timestamp: July 04, 2020, 02:25:42 pm
content: Do your part to raise awareness of this deficiency... write a 1-star review of it pointing out the problem (one other person has done this but still gave it 4 stars). Also add (and answer) a question to their QA list for the product... something along the lines of "What's the power rating of the regulator used on this board and will it cause problems?" Won't get your money back but at least you might save some other people from some grief.

author: DrG
author_rank: Super Contributor
timestamp: July 04, 2020, 03:31:00 pm
content: Interesting.Here is another thread on the matter.https://www.letscontrolit.com/forum/viewtopic.php?t=6603The OP there makes a good point here..This low-dropout or LDO regulator has SMD marking code 4A2D which leads to the Torex XC6204. From this LDO there are 150mA and 300 mA versions.The 300mA is the XC6204 E to H type. The SMD marking code 4A2D gives no clue on a 150 or 300mA version.So, seeing a 4A2D on the board does not mean it has this problem. I have a D1 Mini V3 and I don't appear to have the under powered 150ma version.If there is some good news here it is that you can get the 300 mA version (a G type as I am browsing) at Mouser for about 25 cents US.

author: Peabody
author_rank: Super Contributor
timestamp: July 04, 2020, 03:46:09 pm
content: I got the exact same thing from Banggood, and it works fine. It has the same 4A2D marking on the regulator. However, I'm using the external antenna with the zero-ohm jumper moved over. I don't think I ever tried it with the on-board ceramic antenna, so I don't know how well that works.This has a lot of good reviews on Bangood, so it's possible you just got a bad copy. But you might want to try putting a large cap on the 3.3V pin and see if that makes any difference. It will if the regulator is the problem. Something like 1000µF if you have one.I'm not sure the reddit piece is correct. The regulator comes in both 150 and 300 mA versions, and it's not clear how you tell the difference. Anyway, mine works fine from my mailbox to my router inside the house.But generally I agree about Banggood and Paypal. If you have to return an item to China to get a refund, you aren't protected.

author: chevybeef
author_rank: Contributor
timestamp: July 04, 2020, 03:50:14 pm
content: For GDP orders, there is free delivery to United Kingdom on orders of £33 or more. A delivery charge of £12 will be billed on all orders less than £33.

author: exe
author_rank: Unknown
timestamp: July 04, 2020, 03:59:52 pm
content: Are you powering from usb? I suggest try different usb ports and different usb cables (I had same problem with my esp8266).

author: Monkeh
author_rank: Super Contributor
timestamp: July 04, 2020, 04:00:22 pm
content: Quote from: DrG on July 04, 2020, 03:31:00 pmThe OP there should read the datasheet, because he's wrong.4A2D is a 150mA, active-high with pulldown, 3.3V regulator. 4A2D would be a 300mA part.

author: DrG
author_rank: Super Contributor
timestamp: July 04, 2020, 04:03:59 pm
content: I think the OP is going to have a difficult time with a return because it is an unusual situation.In all fairness to any vendor, people crash there ESP8266s for all sorts of reasons and you can't expect them to give you a refund on that basis alone.In this case, however, there is ample evidence that an under powered regulator appears on some boards and that regulator does not have a 300 mA output.If it is the 150 mA output version, it is crap. If it is a counterfeit that has a 150 mA output, it is crap. As I recall the specs on the D1 do say a 300 mA regulator. In any event, you can't get by with 150 mA. If that is the case, the OP absolutely has a claim.So, now you have to prove that the board is defective and that it is not your programming. A picture of the board will not do that.Loading the board and looking at a voltage drop on the regulator like this fellow didhttps://www.reddit.com/r/esp8266/comments/9itox8/survey_did_you_get_a_150ma_regulator_on_your/e6yybcf/"I bought two wemos from eBay and arrive a couple weeks ago. Voltage regulator is the 4B2X.I did a quick current test while the esp8266 is running a continuous WiFi scan. Current draw from usb 5volt port while esp8266 running is 80ma.Voltage at 3.3 pin terminal is 3.250voltsWhile drawing a additional 100ma at the 3.3volt pin terminal, the voltage drops down to 3.0volts. The WiFi scan still runs. If I increase the current draw to about 150ma, the board resets/crash due to regulator voltage drop."Makes a pretty convincing case to me. I don't imagine a vendor wants to hear it though.Again, replacing the regulator may be the best way forward in reality.

author: chevybeef
author_rank: Contributor
timestamp: July 04, 2020, 04:13:24 pm
content: @DrG I believe an underlined 'A' indicates the 300mA version.Gives me hope to hear your's is working @Peabody. I will try the external antenna and caps now that there's no chance of a refund.@exe I have tried powering from an external 5V supply instead of the USB.I can get the XC6210B332MR regulator off eBay for £2.69 that can supply 700mA if it comes to that.

author: DrG
author_rank: Super Contributor
timestamp: July 04, 2020, 04:19:08 pm
content: Quote from: Monkeh on July 04, 2020, 04:00:22 pmAre you sure? Look at this data sheet:https://www.torexsemi.com/file/xc6204/XC6204-XC6205.pdfNote first (on the first page):Maximum Output Current :150mA300mA(XC6204 E to H type)Now look at the marking guides for that package XC6205[edit: 6204 NOT the 6205, that was my typo] SOT-25.Show me how the four marking codes discriminate the VERSIONS E-H Type?The 'A' or the 'D' in 4AD2does not do so.I looked at the data sheet before I made my first post in this thread and again after I looked at your post.I think you have it wrong and the OP (that I referenced) has it right. But, look, if I am wrong about that, I can admit it. But, please, go through the explanation so that I (and others) can understand.Thanks

author: DrG
author_rank: Super Contributor
timestamp: July 04, 2020, 04:20:38 pm
content: Quote from: chevybeef on July 04, 2020, 04:13:24 pmCool if that is the case, but is that written somewhere, like in the data sheet? Missed it if it is.

author: Peabody
author_rank: Super Contributor
timestamp: July 04, 2020, 04:21:12 pm
content: Quote from: Monkeh on July 04, 2020, 04:00:22 pmMaybe so, but mine doesn't have the underlined A, and it works fine. And there are almost 300 reviews on Banggood, with a 4.96 average rating, none below 4. So even if it's 150mA, that seems to work well enough for most. But I still think adding the capacitor will make a major difference if it's the regulator that's marginal.One alternative is to get the real thing from the Lolin store on AliExpress - if you aren't in a hurry. It has a very good regulator, and doesn't really cost that much more. If you aren't in a hurry.

author: Monkeh
author_rank: Super Contributor
timestamp: July 04, 2020, 04:28:38 pm
content: Quote from: DrG on July 04, 2020, 04:19:08 pmSure. Per page 44 ofthe datasheet, a bare A indicates an XC6204A with a voltage betwen 3.1V and 6V in 100mV increments. An underlined A (A), an XC6204E, with the same voltage specification. The A variant being 150mA, and the E being 300mA, both active-high with a built in pull-down resistor, per page 3.I admit I took a few looks at those pages to decipher that.

author: chevybeef
author_rank: Contributor
timestamp: July 04, 2020, 04:29:21 pm
content: Quote from: Peabody on July 04, 2020, 04:21:12 pmAs soon as I discovered the reddit post I ordered a genuine D1 mini v3.1 off eBay to continue development. It worked like a charm and I've subsequently bought another two.

author: Peabody
author_rank: Super Contributor
timestamp: July 04, 2020, 04:36:35 pm
content: Quote from: chevybeef on July 04, 2020, 04:13:24 pmJust as a test, if you have a 3.3V external supply that you can apply at the 3.3V pin, that would at least test whether the regulator is the problem because that's coming in after the regulator. You would need to disconnect USB to do that test. Or if you have a scope, you can see what happens at the 3.3V pin when the D1 is transmitting. If the voltage sags significantly, that would indicate an insufficient regulator. If I get a chance this weekend, I'll see how much sag mine sees. It is driven by an 18650 at the 5V pin.

author: DrG
author_rank: Super Contributor
timestamp: July 04, 2020, 04:37:25 pm
content: Quote from: Monkeh on July 04, 2020, 04:28:38 pmAhhhh You are RIGHT. I looked at that table plenty and complete skipped over how they marked the E-H packages (A,B,C,D).I stand corrected and thanks.{Now I am wondering what will happen to mine (with a plain A) once I loaded it}

author: wraper
author_rank: Unknown
timestamp: July 04, 2020, 04:39:35 pm
content: Quote from: chevybeef on July 04, 2020, 11:15:24 amThey are somewhat wrong in their claims and most likely cite a different VREG. Most likely it's a super cheapo 3.3V 300mA NATLINEAR LN1134A332MR-G or something similar with the same markinghttps://lcsc.com/product-detail/Low-Dropout-Regulators-LDO_NATLINEAR-LN1134A332MR-G_C141419.htmlhttp://www.natlinear.com/uploadfiles/2014/LN/LN1134_E.pdf

author: chevybeef
author_rank: Contributor
timestamp: July 04, 2020, 04:43:32 pm
content: Quote from: Peabody on July 04, 2020, 04:36:35 pmThanks that's a test I can do with an external 3.3V supply. Unfortunately I don't have a scope though.

author: DrG
author_rank: Super Contributor
timestamp: July 04, 2020, 04:51:46 pm
content: Quote from: wraper on July 04, 2020, 04:39:35 pmSo, a 4A2D marked regulator, CAN, in fact be 300 mA out?I guess it needs to be loaded and measured for a voltage drop.

author: wraper
author_rank: Unknown
timestamp: July 04, 2020, 05:00:29 pm
content: Quote from: DrG on July 04, 2020, 04:51:46 pmYep. I don't believe it's XC6204A because it would be too expensive. Fun fact about LN1134A332MR-G, datasheet says that the last symbol is a lot code. But I had several orders of them over a few years, and marking always was 4A2Ddespite them obviously being from different batches due to slight differences in marking and package.

author: Monkeh
author_rank: Super Contributor
timestamp: July 04, 2020, 05:08:10 pm
content: Quite possible it's another part which may or may not really be capable of 300mA. It could also be down to the amount of copper connected for heatsinking, or perhaps even using very thin foil to save costs. Frankly, it could be any damn part - they could easily have just said "We want something which says 4A2D" and soldered on whatever they got..

author: chevybeef
author_rank: Contributor
timestamp: July 04, 2020, 05:22:04 pm
content: Quote from: Peabody on July 04, 2020, 04:36:35 pmI tested with an external 3.3V and it still struggles to connect to WiFi so tomorrow I'll move the zero ohm and test with an external antenna.

author: DrG
author_rank: Super Contributor
timestamp: July 04, 2020, 05:45:36 pm
content: Quote from: wraper on July 04, 2020, 05:00:29 pmThat makes some sense. Mine is a v3.0 It has a regulator marked 4A2D just as the OP's (although his is a version 1.0 board). I got mine from Banggoodhttps://www.banggood.com/Geekcreit-D1-Mini-V3_0_0-WIFI-Internet-Of-Things-Development-Board-Based-ESP8266-4MB-p-1264245.html?cur_warehouse=USA#customerQAand it was cheaper when I bought it back in 2018. I never had any problems with it although I don't remember doing much with it and it has been sitting in a drawer for a while- giving way to ESP32 for a few projects.I hooked up an admittedly cheap USB meter and ran some programs. I can see it hit 220-240 mA regularly, presumably when transmitting (as in a little client program). Not a great test, but no crashes at all. I don't think mine is a 150 mA regulator.I think that the problem is real and I have now read about it in a number of places, but it may be more complicated (what else is new?).

author: Peabody
author_rank: Super Contributor
timestamp: July 04, 2020, 06:58:02 pm
content: Test results from Peabody Labs. I put my scope on the 3.3V pin, and triggered my mailbox notifier. I set the scope trigger at 0.1V below the normal do-nothing voltage, which is actually more like 3.27V. With the scope trigger set to falling, single shot mode, the scope didn't trigger until the notice had been sent and the circuit shut down. So in effect there was no noticeable sag at all while the system was active.Mine is at least one example of a 4A2D regulator that's plenty good for this module when it's transmitting, which is the highest current draw. I don't know if it's 150 or 300 mA, but it works well enough. I've always doubted the reddit thing. You don't have a regulator problem unless you get voltage sag under load, whatever the regulator marking may be.Quote from: chevybeef on July 04, 2020, 05:22:04 pmYeah. You may well have a defective module, but it doesn't appear that the regulator is the problem - because your test bypassed the regulator and the module still misbehaves.Quote from: chevybeef on July 04, 2020, 04:43:32 pmWe can get you a dirt-cheap scope that's perfect for stuff like this. Where? Banggood of course. :-) It's the DSO150 kit scope, and for everything, including converting it to battery power, you're probably looking at $35. And you do want to get it from Banggood because all the Ebay and Aliexpress DSO150s are fakes/clones which can't do firmware upgrades. Banggood's stock is genuine. Anyway, it's a cheap little single-channel scope that's really useful for Arduino-type stuff.

author: DrG
author_rank: Super Contributor
timestamp: July 04, 2020, 07:02:45 pm
content: LOLIN D1 mini Pro V2.0.0 (16 mb) from Alihttps://www.aliexpress.com/item/32724692514.html?spm=a2g0o.detail.1000060.2.7bd91d15Dt4Q41&gps-id=pcDetailBottomMoreThisSeller&scm=1007.13339.146401.0&scm_id=1007.13339.146401.0&scm-url=1007.13339.146401.0&pvid=c865bb02-0794-4401-abd3-09c58fba28f8&_t=gps-id:pcDetailBottomMoreThisSeller,scm-url:1007.13339.146401.0,pvid:c865bb02-0794-4401-abd3-09c58fba28f8,tpp_buckets:668%230%23131923%2358_668%23808%233772%23921_668%23888%233325%2319_668%232846%238115%23807_668%232717%237564%23692_US 5.00 + 5.67 shippingGenuine/Original LOLIN D1 Mini Pro V2.0.0 WiFi IoT Development Board 16MB (from Amazon)https://www.amazon.com/Genuine-Original-Development-MicroPython-Nodemcu/dp/B07QDFP3WC?th=1US 11.60 free shippingBanggood (as per OP's link) Geekcreit® D1 Mini Pro-16 Module (note included antenna)US 9.04 + 2.99 shippingThe schematic for the D1 mini pro (as well as the D1 mini which I have a clone of) lists the regulator as an ME6211 listed as 500mA outhttp://www.datasheet-pdf.com/PDF/ME6211-Datasheet-Microne-825724In this case, it looks like the clones definitely have a risk associated with them and it is not simply a case of you get what you pay for.

author: chevybeef
author_rank: Contributor
timestamp: July 04, 2020, 07:13:57 pm
content: Quote from: Peabody on July 04, 2020, 06:58:02 pmIt certainly looks that way at the moment. Test with external antenna should prove it tomorrow.Is it this one:https://www.banggood.com/Original-JYETech-DSO-SHELL-DSO150-15001K-DIY-Digital-Oscilloscope-Unassembled-Kit-With-Housing-p-1093865.html?DCC=GB&currency=GBP&cur_warehouse=UK@giosif has one listed for sale with a bench power supply that I'm quite interested in too:https://www.eevblog.com/forum/buysellwanted/fs-(uk)-tti-power-supply-and-iso-tech-scope/

author: DrG
author_rank: Super Contributor
timestamp: July 04, 2020, 07:38:22 pm
content: Quote from: chevybeef on July 04, 2020, 07:13:57 pmI know I am butting in here, but I purchased, from Banggood, the scope that you linked. It works and surprisingly so. I upgraded after a couple of years using that one. I have no regrets at all with the purchase. It was a semi kit (smt chips mounted on a board) and took a short evening for me to build.

author: Peabody
author_rank: Super Contributor
timestamp: July 05, 2020, 02:35:24 am
content: Yes, that's the one. But you'll have to add a 9V power supply and a real scope probe such as the P6100 shown at the bottom of that page. The probe that comes with it has two alligator clips, which is no good. Then if you want to convert it to battery powered, you would need the battery, a charger module, and a boost converter module, but you wouldn't need the 9V supply. There's a very long thread on the JYETech forum about various ways to do that. It's not essential, but makes the scope easier to use and since it's not referenced to earth, there's less risk of blowing things up.There are a number of videos on Youtube on the scope and on the battery modification.Of course the analog scope is a real scope. Two channels even. :-) It's much more capable than the dinky DSO150, assuming it continues to work.

author: exe
author_rank: Unknown
timestamp: July 05, 2020, 07:45:34 am
content: Quote from: chevybeef on July 04, 2020, 05:22:04 pmHow does it struggle to connect? Does it crash or signal is poor?

author: chevybeef
author_rank: Contributor
timestamp: July 05, 2020, 09:47:05 am
content: Using the external antenna makes no difference.So to summarise, won't reliably connect to wifi or send data when:using onboard antenna and connected to USBusing external antenna and connected to USBusing onboard antenna and external 3.3V supplyusing external antenna and external 3.3V supplyusing external antenna and external 5V supplyWhat can I learn from this:Keep the packaging from Banggood, they'll ask for photos of itPossibly take a video of opening the packageBanggood will make it hard to get the RMA, requiring photos, videos, numbers off packaging, detailed descriptionEven if you get an RMA they'll make you return the item to China, possibly with short deadline making it infeasibleDon't think payPay will protect you, they seem to let the supplier dictate the termsVerify theories found online, could have saved time just testing with an external 3.3V supplyHaving a scope could have been useful in verifying the 3.3V tooThe people in these forums are amazingly helpfulAt the end of the day it's still a defective item and I'm out of pocket but the knowledge gained was worth it.I am concerned about how I'm going to overcome my suspicion of Chinese goods because I want to buy some lab equipment and all made in China it seems. It's made worse by recent purchases of simple things like 2 batches of resistors not in spec, the XR2206 debacle, and Seon's PnP drama.

author: exe
author_rank: Unknown
timestamp: July 05, 2020, 10:46:35 am
content: How far are you from the access point? In my experience esp devices have very poor range (using internal pcb antenna).

author: chevybeef
author_rank: Contributor
timestamp: July 05, 2020, 10:55:24 am
content: Quote from: exe on July 05, 2020, 10:46:35 amLess than 10m but my genuine D1 mini's all work fine from my desk and I even have one outside in the car which is at least 15-20m away and it connects every 5 minutes in around 4.3s.

author: Peabody
author_rank: Super Contributor
timestamp: July 05, 2020, 02:24:18 pm
content: Quote from: chevybeef on July 05, 2020, 09:47:05 amSince shipping to and from China has become essentially unworkable, I've resorted to buying from Ebay sellers in the US. And I've found the prices to be reasonably close to the delivered prices from Banggood, etc., now that they're all charging for shipping from China. I've actually had pretty good luck with Chinese products over the years, but if there's a problem with something from a local seller, returning it is feasible, and in many cases the seller will pay the return shipping. And you have the threat of negative feedback, which you don't have with Banggood and AliExpress. Unfortunately, Banggood is the only source I know of for a genuine DSO150 at a low price.I think you should leave a bad review at Banggood, including about being unable to get a refund. That's about all you can do.And I would not be buying any expensive test equipment from a Chinese seller. You don't have a choice that the gear is made there, but you should buy it from a local source where you have recourse if something goes wrong.XR2206? PnP? I guess I need to read up on those now.

author: Peabody
author_rank: Super Contributor
timestamp: July 06, 2020, 02:17:17 pm
content: Just to clarify about the DSO150 scope from Banggood. I have a contact at JYETech who tells me the kit comes with the alligator clip probe, but the assembled unit comes with a regular scope probe inside the box. I think it's a P6020, which is ok for this scope. The comments on the Assembled listing seem to confirm that it comes with a real probe, despite what the picture shows. At the moment there's only about US$9 difference between the kit and the assembled version, which is just a bit more than the cost of a real probe. So it seems to me the assembled version is the way to go, since soldering the kit is not without risks. But you may have to get it from the China warehouse, which may take a long time. The assembled version pictures also show a 9V power supply, but I wouldn't count on that being included unless you specifically ask about it and get confirmation that it's included, and whether US or EU plug.https://usa.banggood.com/Original-JYETech-Assembled-DSO-SHELL-DSO150-Digital-Oscilloscope-Module-9V-p-1211151.html

author: chevybeef
author_rank: Contributor
timestamp: July 07, 2020, 10:21:38 am
content: Quote from: Peabody on July 06, 2020, 02:17:17 pmQuote from: exeQuote from: DrGI've added this to my cart thanks. Once this claim is settled I'll make a decision on buying. The latest email from Banggood says they are going to escalate my case. That was 2 days ago so I don't hold out much hope.I did another test WITHOUT an antenna at all and guess what, same results: struggles to connect but connects regularly when close (2m) to the AP. There's only one capacitor (5.6p on the D1 mini schematic) between the chip and zero ohm for the antenna. I could try a bit of flux is that area and heating the chip pins and the cap and see what comes of that? Changing the cap is a possibility but I don't have one handy at the moment. Not sure what else to do.

author: Peabody
author_rank: Super Contributor
timestamp: July 07, 2020, 02:28:19 pm
content: I only have the schematic for the D1 Mini, not the Mini Pro. But assuming it's the same in this area, and if you can find which cap it is, I would test for continuity between pin 2 of the 8266 and the top of the capacitor lead, and then between the top of the other lead and the jumper. If those test good, then the underlying solders should be good.

author: chevybeef
author_rank: Contributor
timestamp: July 07, 2020, 02:45:25 pm
content: Quote from: Peabody on July 07, 2020, 02:28:19 pmI've tested continuity and that the capacitor is not a dead short. I don't have a component tester. I've found a replacement on Farnell but might be a challenge without a hot-air machine.

author: Peabody
author_rank: Super Contributor
timestamp: July 07, 2020, 02:58:13 pm
content: You tested continuity across the capacitor? What I was suggesting was to test the solder connections of pin 2 and the capacitor. Anyway, as a practical matter, I don't know how you would test the cap itself. Or even replace it. And you're going to spend more trying to do that than the module is worth. The problem could be anywhere, even inside the 8266. Your chances of fixing this are not high.But I have to admit - if performance is exactly the same whether the external antenna is connected, or no antenna is connected, that suggests that the only functioning antenna is either just pin 2, or the trace between pin 2 and the cap.

author: chevybeef
author_rank: Contributor
timestamp: July 07, 2020, 03:11:14 pm
content: Quote from: Peabody on July 07, 2020, 02:58:13 pmI've tested continuity AND that the capacitor is not a dead short.I think you right about the pin or the trace to the cap being the antenna now and only a couple of cents worth of minuscule capacitor to test if that's the culprit, frustrating. Judging by how it went moving the zero ohm, I might be able to get the cap off and possibly on again. I'll leave it for now but when I buy more stuff on Farnell I'll probably buy those caps and give it a go because the thrill of getting it working will be great.

author: exe
author_rank: Unknown
timestamp: July 07, 2020, 03:15:28 pm
content: You can try soldering a new cap on top of the old cap. Although, I managed to desolder caps with just iron. Especially easy with knife-like shape when you can touch two pads simultaneusly. Otherwise heat one side first, then quickly the other (requires some practice).UP: like in this video:

author: chevybeef
author_rank: Contributor
timestamp: July 07, 2020, 03:20:44 pm
content: Quote from: exe on July 07, 2020, 03:15:28 pmThank you, the practise isn't much of an issue but my ageing eyes and the tiny scale of the cap, 1005. I have some magnifying glasses and helping hands to assist though.

author: cowana
author_rank: Frequent Contributor
timestamp: July 07, 2020, 03:21:53 pm
content: Funny timing of this thread - I had exactly this issue with a recently purchased Wemos D1 Pro board, purchased from Aliexpress. It only returned a fraction of the expected wifi stations during a scan, and really struggled to connect (either to an AP or as a STA). Using the internal or external antenna made little difference to signal strength or the number of reported access points.After a bit of investigation, I determined the error was due to the ESP8266 crystal; desoldering and replacing the 26MHz crystal with one from a donor board fixed the issue, and the board worked exactly as expected (seeing 20+ wifi stations and connecting reliably).Interestingly soldering the 'broken' crystal on the donor board didn't stop the donor board working - I suspect the issue was the value of the loading capacitors chosen, rather than the crystal being faulty itself. If I had wanted to investigate further I could have checked the output frequency of the crystal to check which way it needed pulling (to trim it back in spec); but as I've now got two working boards I didn't bother.As feeding the board from an external 3.3v supply didn't fix your board (and you have the same symptom), I'm sure your problem is the same issue (quite possibly from the same batch); I'd put money on replacing the crystal as fixing your issue too. The regulator thing is likely a non-issue; 150mA continuous should be fine for a bare module anyway, as they happily run down to 2.7v or so....just looking at your photo of your board again, the crystal looks suspiciously like it says '25 MHZ' on it. The BG photo, my module and the official schematic all use a 26MHz crystal - am I reading your photo wrong?

author: chevybeef
author_rank: Contributor
timestamp: July 07, 2020, 03:37:18 pm
content: Quote from: cowana on July 07, 2020, 03:21:53 pmIncredible coincidence, the timing. Mine did exactly the same during a scan etc.Quote from: cowana on July 07, 2020, 03:21:53 pmYou've just saved me a lot of frustration, thanks.Quote from: cowana on July 07, 2020, 03:21:53 pmI could try doing the same with another D1 mini I have.Quote from: cowana on July 07, 2020, 03:21:53 pmJust de-soldering the crystals is going to be a challenge.Quote from: cowana on July 07, 2020, 03:21:53 pmYes, the crystal says 26MHz on the board.

author: DrG
author_rank: Super Contributor
timestamp: July 07, 2020, 03:40:33 pm
content: I have seen this kind of setup before. The board is setup for the internal antenna. You can't simply connect the external antenna and expect it to work. This is why you see no change at all with the external antenna.I believe that you need to move the 0 ohm resistor in order to use the external antenna. See pic - hopefully you can see the traces and how moving the resistor to a position 90 degrees counter clockwise puts it into the external antenna position.[ Attachment Invalid Or Does Not Exist ]N/M you already did that from your pic posted - sorry.

author: chevybeef
author_rank: Contributor
timestamp: July 07, 2020, 03:47:50 pm
content: Quote from: exe on July 07, 2020, 03:15:28 pmVery useful video thank you.

author: Bassman59
author_rank: Super Contributor
timestamp: July 07, 2020, 10:59:08 pm
content: Quote from: chevybeef on July 04, 2020, 11:15:24 amCan you start a credit-card chargeback? Here in the US, if you purchase something with a credit card and the product is not to your satisfaction (doesn't work, isn't what was advertised) and the seller is non-responsive, all you need to do is call the credit card issuer and start a credit dispute. Many cards/banks allow you to do this online, too. The credit card issuer will generally give you an immediate credit of the amount, pending their investigation/processing, and soon enough you'll hear back that they've dealt with the vendor in your favor.Here's the best part. If a vendor gets enough chargebacks, the credit issuers simply won't allow them to process credit transactions. That is the best way to kill bad vendors. Sure, they're Chinese and will simply rename themselves and start fresh, but you've got your money back.

author: cowana
author_rank: Frequent Contributor
timestamp: July 17, 2020, 07:55:28 pm
content: I recently received another Wemos D1 Pro board with similar symptoms (fewer than the expected number of WiFi hotspots seen, instability with connection), so I did a bit more investigation.On my original faulty module (which started working when I replaced the 26MHz crystal), the crystal's loading capacitors measured as 20pF each.On the second faulty module (bought from a different seller a month later), the crystal's loading capacitors also measured as 20pF each.On a schematic I found online (no idea to the accuracy), the capacitors are marked as 10pF each.On a working Wemos D1 Pro board (purchased from another seller months ago), the capacitors measure as 8.2pF each.I replaced all the 20pF capacitors on my two dodgy boards with 8.2pF caps, and they both immediately sprung into life - reporting the full list of WiFi hotspots in range, and working reliably. I'm confident the incorrect capacitors being fitted (20pF not 8.2pF) was the fault all along, and my previous corrective action of replacing the crystal just happened to make it work due to reduced internal capacitance in the crystal.Hopefully this information might be useful to other people with the same symptoms - would appear there's been a recent batch of D1 Pros with the wrong value parts!

author: chevybeef
author_rank: Contributor
timestamp: July 20, 2020, 12:28:59 pm
content: Quote from: cowana on July 17, 2020, 07:55:28 pmI'm happy to report that I did the same and got the board working so thank you very much for the information.Definitely wasn't easy with my eyes and the equipment available.Seems Geekcreit need to be treated with caution:

author: exe
author_rank: Unknown
timestamp: July 20, 2020, 02:05:19 pm
content: Quote from: chevybeef on July 20, 2020, 12:28:59 pmI would say it's not something specific to Geekcreit or any other "brand", but in general cheap Chinese goods are often worse than they try to appear. In this case I'd say they just sell 5% resistors as 1% for the price of dirt. I'd say it's a good deal if one has realistic expectations. Many users (including myself) are disappointed by fake specs of Chinese parts, but that's the reality. I still use these parts in non-critical parts of circuits (such as digital logic).In my opinion it makes little sense to buy any precision parts from China unless one wants to gamble and has means and will to verify the actual performance.

author: robca
author_rank: Frequent Contributor
timestamp: July 28, 2020, 09:27:49 pm
content: Quote from: ledtester on July 04, 2020, 02:25:42 pmJumping on this late. In the past, Banggood reviews were mostly reliable.In the last 3 years or so, Banggood only publishes 5 and 4 star reviews, rarely 3 stars. Nothing lower. If you write a 1 or 2 stars review, it's simply never published. Unsurprisingly, no product on Banggood has fewer than 4 stars (well, there might be one or two from the past).Some people even resorted to writing "negative" 5 star reviews. The rating is 5 stars, but if you read the review it's highly negativeAlso, Banggood keeps changing providers for the same SKU. So you buy something once and it's ok, next time it's different and not ok.I still use Banggood, but I rely less and less on it

author: exe
author_rank: Unknown
timestamp: July 29, 2020, 08:05:00 am
content: That's sad as I was looking for an alternative to aliexpress...

author: robca
author_rank: Frequent Contributor
timestamp: July 29, 2020, 04:17:44 pm
content: Quote from: exe on July 29, 2020, 08:05:00 amAs long as you don't rely on the reviews (or take the time to read everything and spot the "5 star negative reviews"), Banggood is still one of the cheapest and most reliable Chinese sources. Keyword being "Chinese", so problems can always be expectedA classic case is the Blue Pill STM32F103 board. Until a year ago or so, most had a real STM32F103 on board, these days pretty much all those boards have chinese clones of the STM32. Very few sellers changed the pictures, so you might see the old Blue Pill but receive the one with the cloned processor (some work ok, some not as much)In my experience, it's always possible to get a refund from Banggood in case of problems. It takes longer than in did in the past, and the standard process is:me: there is a problem, here is the video and pictures that show the problem, Also a photo of the shipping envelope (for some reason, they ask for it... I suspect because most people throw it away so they have an excuse not to refund)banggood: can you send us x (usually something I already sent)me: I did, here it is againBG: sorry for that, would you accept 200-500 points as a solutionme: no, I have too many points already, and you can't use them for most products anyway. I want a refundBG: will get back to you, please waitme, after 3 days: any news?BG: we are sorry, would you accept 200-500 points?me: no, i will not, I want a refund, if not I will escalate to PaypalBG: we have processed your refund, you will receive it in a few days(money arrives)sometimes I ask for a partial refund if the problem is minor. I'd say that only 1 order in 30-50 has problems, and all considered (prices, inventory), I have good experiences with Banggood. Clearly not Amazon, but still one of the most reliable Chinese sellers

author: Peabody
author_rank: Super Contributor
timestamp: July 29, 2020, 10:26:40 pm
content: I recently bought two batches of Arduino Pro Mini clones from U.S. Ebay sellers (to avoid multi-month shipping delays from China). I remove the voltage regulator and power-on LED and use them for battery-powered projects that spend a lot of time in sleep mode. Modified that way, they sleep at 1uA or less. But all these new Minis sleep at 150uA. In another thread here, I'm working on figuring out whether the Atmega328P-AU chips are counterfeit or genuine. But if they are counterfeit, then I'll be faced with the problem of finding a source of Pro Mini clones which use genuine 328Ps. I had thought to try Banggood, but from what everybody here says, that may not be good option. Is there a better option (other than Sparkfun at a much higher price)? I've actually had good luck with Arduino clones in the past - Nanos and such. This is the first problem I've had.

author: robca
author_rank: Frequent Contributor
timestamp: July 30, 2020, 12:08:26 am
content: I saw your other thread. If those are fakes, it would be the first time ever that a 328p is reported as fake. There have been a lot of reports in the past, but none proved to be correct (either people received completely fake chips, not working as a 328p, or they mistakenly thought one was fake). Not saying it's not possible, just a firstOutside of Sparkfun, Adafruit or the Arduino store itself, the only other safe alternative would be to replace the Atmega with one bought from Digikey or Mouser (if you are in the USA). If there really are fake 328p around, pretty much all Chinese sources will have that chip now or very soon. And the majority of Chinese sellers have no idea what they are selling, they simply pass along what they get from their suppliers (just try looking at all the other items any of the eBay sellers also sells in their store, it's a mishmash of everything)

author: Peabody
author_rank: Super Contributor
timestamp: July 30, 2020, 02:41:36 am
content: Well, replacing a 32TQFP chip on a Pro Mini is easier said than done. But I understand what you're saying about fakes being unlikely, and when the second batch arrived, with different markings, but also not sleeping properly, my first reaction was that the chips are genuine. But if true, that means Atmel/Microchip has screwed the pooch on the 328P, which would be truly unfortunate. The only solution for that would be new old stock - 2018 or earlier - and I don't know how you would find a source for that.

author: Monkeh
author_rank: Super Contributor
timestamp: July 30, 2020, 03:29:09 am
content: Quote from: Peabody on July 30, 2020, 02:41:36 amNo, it really isn't. It's a very simple soldering task.

author: robca
author_rank: Frequent Contributor
timestamp: July 30, 2020, 03:39:04 pm
content: Yes, that chip is pretty easy to remove and replace. The safest way to replace it is to cut the pins on the existing chip and then remove the remaining pin pieces from the pads. Then soldering the new chip can be done easily with any decent temperature controlled soldering iron and drag soldering. Clearly the removed 328p in that case is then completely ruinedOr remove the chip with an hot air station and replace itQuad Flat Pack is one of the easiest SMD chip to remove/replace. Might be worth doing on one just to rule out everything else

author: daygp
author_rank: Newbie
timestamp: December 05, 2020, 10:37:22 pm
content: Peabody nailed the wifi problem on the first page of this trail. "However, I'm using the external antenna with the zero-ohm jumper moved over."Its also explained in this video:https://www.youtube.com/watch?v=3lHoG1mu7hY&feature=youtu.be&ab_channel=AlexEamesYou just need very good eye sight.GD