What is DC Resistance of Hakko FX888D Handle Thermistor at Room Temp, Please! - Page 1
Forum section: electronics / beginners

author: SuzyC
author_rank: Frequent Contributor
timestamp: April 13, 2018, 10:42:44 pm
content: Have bought two different economy clone Hakko 8801 model handles for the FX888D soldering station, and they differ very much with room temp. thermistor resistance.One of the them is faker than the other. Both work perfectly and solder very nicely using my microprocessor controller I designed, but the temperature calibrations are way different.They both should be plug-and-play. If you've seen one, you've seen them all, that is all that are genuine originals from Hakko.Specimen number one measures 52-ohm and specimen two measures about 40 ohms at room temp(23 deg-C.).What does your's measure?Would any of you Hakko 888D users be so kind as to measure resistance between pins 4 and 5 (cw counting connector front view, looking at the pins of the male plug) and tell me? You just unplug the handle connector and use any DMM to measure the DC resistance.Also, how long does it take your Hakko to reach 60/40 soldering temperature from room temp. start?Thanks in advance!

author: KL27x
author_rank: Super Contributor
timestamp: April 14, 2018, 12:10:22 am
content: I have 3, but one I just used. So I have a sample of two for you.@76F1. 46.4R2. 47.4R - brand new, unused handpieceUsing a 3mm bevel tip, I have recorded ~17 seconds from a completely cold start to soldering stuff, in the past. The 888 is powered from an AC transformer. I have recorded the peak to peak at 88.8V with essentially no sag under load (I think it's black magic). That comes out to about 26V RMS, if I'm saying that right. Minus w/e is lost in the TRIAC.

author: SuzyC
author_rank: Frequent Contributor
timestamp: April 14, 2018, 12:22:57 am
content: I have no resistance to thank you much, Kl27x, these measurements closely match both of my handles.Only problem, you've measured the heating element resistance, I need the thermistor reading on pins 4-5!

author: KL27x
author_rank: Super Contributor
timestamp: April 14, 2018, 12:28:14 am
content: Hrmm? I though you said it was pins 4 and 5 in your OP. Besides this, I'm pretty sure the heater is between pins 1 and 2, and I'm measuring something like 3.5R. If the heater was 47R, the 888 would only be a 14W station (when cold... maybe 7W station when hot, lol).

author: SuzyC
author_rank: Frequent Contributor
timestamp: April 14, 2018, 12:31:22 am
content: Sorry for my improper measurement pins at first, I've corrected my mistake (I was looking at the back of the connector, solder side of the pins, at first.)Could you try pins 4-5, please! I think the center pin is numbered pin#6 and earth ground and not of any interest to this scientific study.

author: KL27x
author_rank: Super Contributor
timestamp: April 14, 2018, 12:40:36 am
content: My measurements are what they are.47R is between your two samples of 40R and 52R. Why you doubt me?

author: SuzyC
author_rank: Frequent Contributor
timestamp: April 14, 2018, 12:46:14 am
content: No doubt!I was just looking at your posted results and misread them!My mind was expecting to see you write the results something like:1) 47-ohm2) 50-ohm......But, at first glance I thought I saw heater element resistance readings:1.46.4-ohm (~1.5-ohm)2.47.4 -ohm(~2.5-ohm)The one I have that measures about 40-ohms was the much cheaper of the Chinese twins bought. The first one, that matches closely your readings cost about $22(touted as Hi-Quality by the seller), the second out of spec resistance one, only cost me $8, both with free shipping from China.

author: KL27x
author_rank: Super Contributor
timestamp: April 14, 2018, 12:54:59 am
content: Well, glad we cleared that up.But if your heaters are measuring 1.5R, I think your knockoff is a few coils short on the heater.(I have heard genuine Hakko heating elements use a film resistance heater rather than wire coils. When I burn one out, I'll find out if that's true.)

author: SuzyC
author_rank: Frequent Contributor
timestamp: April 14, 2018, 12:58:14 am
content: I have fried more than two now. when you break the white ceramic element cylinder heating element anywhere near the top you will see no wires at all. They are for sure, ceramic film.From the plug pins, I measure about 2.3 to 3.2-ohms on both. The heating elements are consistent in resistance with each other and Hakko originals as I also see about 17-secs from room to full operational soldering temperature with both of them.

author: KL27x
author_rank: Super Contributor
timestamp: April 14, 2018, 01:00:10 am
content: Hmm, interesting that you broke two.I'm 9 years going without any issue. Did you break two genuine Hakko's, or 2 knockoffs?I was under the impression that the sensor is at the top. Maybe that's what you saw.

author: SuzyC
author_rank: Frequent Contributor
timestamp: April 14, 2018, 01:03:36 am
content: I am afraid to say that I've knocked off the knock-off's. Never tried the originals. I like making my own circuits and wanted to make my own Hakko clone soldering station, as cheap as possible, and I've done that and it works great! I used salvaged parts except for the handle resting holder, cleaning sponge and the new Hakko clone handles.One PIC MCU using only two lines of C-code makes a very accurate thermal control for the handle.The first heating element one died due to a mistake while I was first developing my controller circuit. Got white hot and passed on to the nether world of fire and lead.The second one lasted for about two years and I used up a pound or two of solder.

author: KL27x
author_rank: Super Contributor
timestamp: April 14, 2018, 01:19:10 am
content: I made my own station, once upon a time. Worked great, but it was using a cheap Velleman style handpiece and I got tired of fixing and replacing broken handpieces and heaters and worn out tips. The tip selection was also terrible. You definitely chose a better platform.IME, the cheap Hakko clone heaters last somewhere between 1-3 years. I expect them to fail. If not the handpiece breaking at the collar, first. And they are usually coiled nichrome wire.FWIW, you can buy genuine heater/sensor elements from Tequipment for like $22.* Too bad the genuine handpiece costs over 70. I bought two of my 888's at 79.00 each, lol.*OTOH, if you are powering the heater from DC, I would guess that a film element will perhaps be more susceptible to adverse effects and death from electrolytic migration, if, indeed, the genuine elements are film.

author: SuzyC
author_rank: Frequent Contributor
timestamp: April 14, 2018, 01:36:52 am
content: Never ever seen any of the clone heating elements made of nichrome wire, all were genuine ceramic elements. I attribute the short life of the second handle due to it idling at soldering temperature for hundreds of hours. Never had any mechanical problem with even the cheapest handle I bought.From the first time I used the clone Hakko handles with my controller, I was truly pleased with the fast heating up, having high enough power to easily unsolder just about anything, and the lightweight design and especially how easy it was to make a circuit to achieve very stable and precise temperature control with just a TRIAC controlled by a MCU and just a few other small components.I have been always using an approx. 30V RMS CT at 3A transformer salvaged from an old solid-state 60W audio amp.What is so great is that I can swap tips by just swapping the whole handle, something that cannot be done with the OEM without buying several expensive original replacement handles.As far as tips go, it uses genuine Hakko or Hakko clone tips, so no problem there.

author: KL27x
author_rank: Super Contributor
timestamp: April 14, 2018, 01:55:10 am
content: The cloners must be stepping up their game. I have seen many pictures of wound nichrome 936 heating elements.But...QuoteI can't even guess how many hours I have. But there was a long stretch early on where it was used more days than not. For the last 3-4 years I have done less prototyping and breadboarding, and more CAD design and production SMD soldering. I maybe solder 2x a week, but when I turn it on, it is on. When I break, when I eat, when I decide I'm going to watch TV for a few hours. I have made a preset for standby, but I stopped using it, because nothing breaks or wears out anyway. I wanna say I bought my first analog 888 in 2008; it was almost immediately after seeing Dave's review back in the day and my current iron had broken 3 times, by then. And I have used the same handpiece as my primary, ever since.When I took on assembly, and when I figured out how much time and effort I saved by having the right tips, I immediately freaked and bought backups. All my old irons were essentially useless in that moment. By then, the analog was history. At one point I had four 888's. But eventually I started to figure that I might not live long enough to wear out the first one, and I gave one away! So I have one for home, one for travel, and my analog is preserved for posterity/backup.Over 9 years, I have replaced one thing. My CSF25 tip broke. The inner iron sleeve detached from the tip through heat cycling. It maybe had a bad braze to begin with. Even then, it worked fine until a replacement arrived.

author: floobydust
author_rank: Super Contributor
timestamp: April 14, 2018, 02:08:32 am
content: FX-888 wand at room temp 22°C:Heating Element 3.41R (pins 4,5)Sensor 46.7R (pins 1,2) and 0uV likely not a thermocouple

author: amyk
author_rank: Super Contributor
timestamp: April 14, 2018, 03:42:43 am
content: Look at page 11 ofthe manual."a. Between pins 4 & 5 (Heating Element) 2.5 - 3.5? (at time of room temperature)b. Between pins 1 & 2 (sensor) 43 - 58?c. Between pin 3 & Tip 2? or less"Pinout is shown.Also worth reading this very detailed thread:https://www.eevblog.com/forum/reviews/genuine-vs-fake-hakko-936-ceramic-heater-a1321/Note that some clones, while almost identical in appearance, use thermocouples instead of thermistors/PTCs.

author: KL27x
author_rank: Super Contributor
timestamp: April 14, 2018, 07:58:51 am
content: I remember the first couple pages of that thread. I didn't remember the last two, thankfully.So it seems like you can buy potentially excellent clone heater/thermistor units for dirty cheap, if you know where to buy them. And that only the worst of the bunch are wire wound.

author: SuzyC
author_rank: Frequent Contributor
timestamp: April 14, 2018, 11:53:51 am
content: Thanks floobydust, that's the info I was seeking.Amyk, It would be impossible to get away with selling a 888D handle with a thermocouple,it just wouldn't work at allin the Hakko station and anyone trying to sell one would be getting so many complaints to drive their business off Ebay. I don't even think physically there is room for a nichrome wire heating element due to the 3-4mm diam of the integrated sensor/heater element. With this small diam of only a few mm, there is just no space for it!As far as 936 heaters go, I wouldn't even bother playing with clones using a 936 design, when the 888D handle is newer, lighter, more powerful, so overall much better in performance.When you compare 936 to 888 you are comparing lemons to Mandarin oranges.I am beginning to suspect there is excessive exaggeration of the quality and reliability of Chinese sold components. In most situations, it is too expensive considering time and labor and especially reputation, to sell crap.It is so just much too easier to make the customer happy with good products at bargain prices. I am pretty sure that most of the volume of purchases are on Ebay and their use of posting customer feedback ratings keeps most crooks at bay.

author: SuzyC
author_rank: Frequent Contributor
timestamp: April 14, 2018, 12:04:05 pm
content: Thanks Amyk, but the excessive tolerance of the thermistor reading shown in the manual(43-ohms OK!) make this spec unusable for comparison. The real value ofresistance measured needs to be tightly controlled and handles manufactured must actually conform to a much tighter spec. in order to sell replacement handles that are completely interchangeable with the original, and the few readings reported here are showing readings between 47-52-ohms, and these values are likely diverging because of differences in room temp.Hakko must be trying to express a resistance spec that fits the range of room temps of those soldering in Northeren Siberia with those techies working in Tripoli.

author: amyk
author_rank: Super Contributor
timestamp: April 14, 2018, 04:44:11 pm
content: There is this thing called calibration...

author: KL27x
author_rank: Super Contributor
timestamp: April 14, 2018, 07:47:48 pm
content: QuoteThere are pictures in the EEV forum thread that Amyk linked. Right on the first page.QuoteIs it? I knew they went from 5 pin DIN to 6 pins in the name of progress... but I thought it was for no other reason than preventing compatibility. They improved the tips. The T18 have better performance than 900M. But they fit on the 936 same as the 888. The 888 station has more power. I always thought they used the same heater/thermocouple as the 936 handpieces.QuoteI agree, in general. China has manufacturing capabilities that take a backseat to no one.QuoteThis is patently false. The manufacturers will make the things to whatever standards they are asked and held to. There are consumers and resellers who WANT low quality stuff. Some businesses make a name out of it. Some buyers like to buy fake soldering iron tips by the dozens. Because buying stuff is fun? Because they like when their equipment goes down and they have to stop and dig around to find their lifetime worth of replacement parts that was such a good deal. That's fine, buyer and seller are both happy.But the problem is many of these products don't have a name/brand. This would require money in marketing for people to even know they can buy it. They put someone else's name on it, like Hakko. So there are multiple levels of quality among the clones, perhaps including some that are very bad. And even the good ones, how good are they? The real deal can last and perform for over a decade. If you broke two clones, already, that's a pretty bad start.The world, in general, is in the addiction of newness. People like wearing things out, throwing them away, and buying new ones. But the heater on a genuine Hakko is not necessarily something I would even consider a consumable/maintenance item.QuoteYes, true. But this is not the only thing. The way the heater is manufactured can change how it works. Does the heat go into the tip, or does it go into the handle. I have used a clone (I think it's called a 939 on eBay) where the handle gets uncomfortably hot just idling in the stand at set temp.* There are clone handpieces that even have added circuitry to monitor handpiece temp and automatically throttle back the set temp to prevent the handpiece from melting itself. This is the one big improvement of cartridge tips, IMO, is that they can output more power in a higher duty cycle, high heat sink application without heating up the handpiece as much. This is the main drawback of the older style irons, IMO. But among the different handpieces and heaters of these classic irons, some of the clones are much worse than the real deal.*I can't even tell if my 888 is on or off by picking up the handpiece. It can idle indefinitely at 320C. It only heats up if doing high duty cycle, high heatsinking production soldering.

author: amyk
author_rank: Super Contributor
timestamp: April 15, 2018, 04:34:32 am
content: My comment about calibration was in response to the assertion that the tolerance should actually be tighter; no it doesn't, because the difference can be calibrated out, and if you replace the heater/thermistor assembly you will need to recalibrate. They even recommend recalibrating when switching tips, since the thermal characteristics will have changed.

author: SuzyC
author_rank: Frequent Contributor
timestamp: April 16, 2018, 03:50:25 am
content: [KL27x: i]"If you broke two clones, already, that's a pretty bad start.The world, in general, is in the addiction of newness. People like wearing things out, throwing them away, and buying new ones. But the heater on a genuine Hakko is not necessarily something I would even consider a consumable/maintenance item. "Here's a tip for you:There is a great convenience and ergonomic advantage to be able to switch handles quickly to best adapt to a soldering task.The early failure was most likely my fault. I had been experimenting using thin shims between the heating element and the tip, since there is some small play, and the shim made took considerable force to insert the heating element and that's how I broke the first heating element, and that's how the second one also likely failed with time. The shim created a great compressive force on the heating element as it reached soldering temperature. Now I that think this shim idea was a bad idea, and likely caused a fail prematurely.I like playing around with "improvements.""I always thought they used the same heater/thermocouple as the 936 handpieces."If you think about it, you likely are confusing a thermocouple with a (47-ohm room temp ptc) thermistor, a bi-metallic thermocouple is a twist of dissimilar metals, this creates is a very low resistance element that generates some few mV prop. to heat.Having only bought four handles so far, and the two working are my soldering tag team.I've never seen any nichrome wound heaters except on some old cheap soldering stations, all the clone Hakko handles I purchased, regardless of price, were made with good quality film heating elements.