Cheap Desoldering station upgrade, now sucks even Harder! No really! - Page 1
Forum section: electronics / projects

author: djos
author_rank: Unknown
timestamp: December 18, 2018, 12:05:28 am
content: G'day all, I've always been mostly happy with my cheap ZD-917 desoldering station, (there's a heap of other companies selling the same product in a standalone unit too - desoldering guts are the same), but always thought it could be even better ...... and it can!Today I finished upgrading mine - there's 2 parts to this upgrade, forcing the pump to always run and adding a tiny electronic air valve inside the handle. Here's some pics I took during the upgrade:The vacuum tubes aren't a tight fit so i added some silicone and then zip tied the tubes on - they are very airtight now!I added some silicone to hold the valve in place and prevent it from jumping around inside the casing under load.yes, it all fits (after breaking out a plastic tab and removing some unneeded rubber jacket from the wiring)and fully reassembled!after cutting the wires to the motor, I used a terminal block to wire the motor to always on and wired the gun-switch in parallel so it could steal 12v for the air valve.NOTE: the motor is wired opposite to how it's marked (-/+ are swapped).I added some yellow electrical tape to the metal frame as the edges on it are a little sharp and I didn't want the wiring etc getting damaged in the long run.Just finished testing!and a bloody good result! this 62 pin header came out out with very little effort! I'd tried to recycle a bunch of these previously (the header is the wrong spec) and ended up destroying the pcb's!and back in her home ready for more action!The parts I used are as follows:12v normally closed air valveterminal block2 extra pieces of wireheat shrink tubeSo this cost me about $5 AUD I reckon and the performance is dramatically better, Im really blown away by how much better it is, and I was expecting an improvement!

author: aargee
author_rank: Frequent Contributor
timestamp: December 18, 2018, 01:52:09 am
content: Great mod!So what happens is the pump pulls full pressure, and opening the valve produces a pulse of full vacuum at the tip, increasing the effectiveness of solder removal?This as opposed to the ramp-up vacuum normally produced when you hit the trigger..Do you think the vacuum pump will hold up to continuous operation?

author: djos
author_rank: Unknown
timestamp: December 18, 2018, 02:50:44 am
content: Quote from: aargee on December 18, 2018, 01:52:09 amThanks mate.So basically the pump runs all the time and creates a pretty strong vacuum in the length of the hose - when you pull the trigger, voltage is applied to the normally closed valve opening it. This creates a virtually instant and strong suction force at the tip and pulls the solder out cleanly.Previously the suction force took time to build up and the solder joints didnt get cleaned out as effectively as they do now.I'm not concerned about the longevity of the pump - in general use I've never left it running when not in use as there's no half-power sleep mode on it.

author: djos
author_rank: Unknown
timestamp: December 18, 2018, 03:05:22 am
content: Btw, the guts of Dave's desoldering station and the gun itself are close enough to the desoldering station half of my unit - so the mod should work just fine on his model.https://youtu.be/Ft50m8UU5WQ

author: texaspyro
author_rank: Super Contributor
timestamp: December 18, 2018, 03:52:12 am
content: The Pace desoldering tools use a technique they call "SnapVac". When you pull the trigger they first drive the motor with (24V?). Then they back off to the normal motor voltage. This works very well.

author: djos
author_rank: Unknown
timestamp: December 18, 2018, 03:58:24 am
content: Quote from: texaspyro on December 18, 2018, 03:52:12 amInteresting idea - i've heard some of the expensive units have spring loaded valves so once pressure builds up enough, the valve opens producing a nice strong instant vacuum. I did toy with the idea of building a relay circuit with a delay that turns on the motor and then 1/2 a second or so later opens the valve ..... TBH I might still do this.

author: beanflying
author_rank: Super Contributor
timestamp: December 18, 2018, 04:09:28 am
content: Interesting idea.It should be able to be added to my Aoyue/Hanba/(insert your clone here) even if the solenoid won't fit in the gun it could sit outside on the hose with a bit of support.Maybe add a pump toggle switch on the base station to prolong the diaphragm life but still allow the tip to preheat and enhance the serenity between sucking? A Delay would drive me nuts doing a run of desoldering.

author: djos
author_rank: Unknown
timestamp: December 18, 2018, 04:58:26 am
content: Quote from: beanflying on December 18, 2018, 04:09:28 amThe mod is dead simple and will work on them all I reckon. just get the little one I linked to and it will fit inside the gun making for a nice stealth mod.Quote from: beanflying on December 18, 2018, 04:09:28 amOh that's a great Idea ... I might just add that to the front panel to turn the pump on and off as required.

author: beanflying
author_rank: Super Contributor
timestamp: December 18, 2018, 05:08:00 am
content: You could also get a gain of rapid volume by adding a reservoir to the system. Could be as simple as a loop of larger diameter hose placed on a T piece broken into the main line before the pump. It would just need to be crush/vacuum proof.

author: texaspyro
author_rank: Super Contributor
timestamp: December 18, 2018, 05:15:21 am
content: I think that running the pump continuously is a bad idea. The pump motors (and pumps) don't seem to be rated for continuous duty and tend to run hot. It looks like they are already somewhat overdriving the system.

author: djos
author_rank: Unknown
timestamp: December 18, 2018, 05:50:51 am
content: Quote from: beanflying on December 18, 2018, 04:09:28 amJust dashed out to the workshop and added a switch - it was too good an idea to ignore.

author: aargee
author_rank: Frequent Contributor
timestamp: December 18, 2018, 06:17:04 am
content: You could have a double action circuit that powers the pump for a few seconds, then triggers the solenoid then off.

author: djos
author_rank: Unknown
timestamp: December 18, 2018, 06:22:39 am
content: Quote from: beanflying on December 18, 2018, 05:08:00 amIt's not really needed, there's more than enough vacuum built up in the hose and it recovers extremely quickly - I had zero issues desoldering that 62 pin header and I consider that to be a heck of a torture test. The whole point is to get that snap suction action and my mod definitely achieves that.

author: djos
author_rank: Unknown
timestamp: December 18, 2018, 06:27:33 am
content: Quote from: texaspyro on December 18, 2018, 05:15:21 amI've added a switch so I don't have to de-power the entire desoldering station - TBH it was mainly the noise that was annoying me. I'm not concerned about reliability, the pump really isn't working that hard.

author: Ranayna
author_rank: Super Contributor
timestamp: December 18, 2018, 08:26:17 am
content: Very nice. I have a ZD-915, so just the desoldering part. Have not used it much, but already had to deal with clogging in the handle. I suspect the stronger vacuum application would help prevent clogging?Just out of curiosity, I could not see it in your pictures. Do you know if the power switch in your model switches only the hot side? My ZD-915 only switches one pole. I live in Germany, and we have unpolarized plugs. Depending on the orientation of the plug, the ZD-915 occasionally "blips" even when turned off. I assume it is related to leakage in what I assume is a switch mode supply when neutral is the switched pole.The switch in my unit even has two poles, and the other power cable is accessible, so I can't understand why they have not wired it in...

author: djos
author_rank: Unknown
timestamp: December 18, 2018, 08:42:04 am
content: Quote from: Ranayna on December 18, 2018, 08:26:17 amCheers. I find that you need to keep the trigger pressed long enough that it has enough time to pull all the solder into the glass tube, then it doesnt clog up.Quote from: Ranayna on December 18, 2018, 08:26:17 amIt is only a single pole switch so yeah it'd be the hot side only - our Aussie plugs can't be inserted incorrectly so as long as your house or workshop wiring is to code that should be good enough (imo).

author: TheNewLab
author_rank: Frequent Contributor
timestamp: December 18, 2018, 11:17:24 am
content: when I look for your ZD-917 unit for sale, I only find the gun only..Where did you get the full unit?

author: djos
author_rank: Unknown
timestamp: December 18, 2018, 07:17:40 pm
content: Quote from: TheNewLab on December 18, 2018, 11:17:24 amI've had mine for a few years now, but I bought it on ebay in Australia.Just look for desoldering station and look for anything that uses the same gun, there's really no significant difference between them all.

author: Gyro
author_rank: Super Contributor
timestamp: December 18, 2018, 07:37:46 pm
content: Quote from: beanflying on December 18, 2018, 05:08:00 amCombine that with a vacuum switch to cycle the pump as needed and you've really got something there.

author: djos
author_rank: Unknown
timestamp: December 18, 2018, 08:00:56 pm
content: Quote from: Gyro on December 18, 2018, 07:37:46 pmI've added the switch at the suggestion from others but the reservoir is not needed as what you need, imo, is just rapid vacuum recovery before the next pin is desoldered. This is all about getting a rapid pressure change at the tip which rips the solder out in one go.

author: macboy
author_rank: Super Contributor
timestamp: December 19, 2018, 04:40:06 pm
content: I think you could achieve a similar effect by having the valve activated on a delay relative to the motor. Even less than one second would help a lot. Then you would have the motor only running when needed, and still have "snap" action vacuum.

author: glarsson
author_rank: Frequent Contributor
timestamp: December 19, 2018, 06:02:35 pm
content: Also keep the pump running for a couple of seconds and don't delay the valve if the pump is already running.

author: SeanB
author_rank: Super Contributor
timestamp: December 19, 2018, 06:12:58 pm
content: Must look into getting one of these, i can then add that vacuum booster as well, as I have all the parts needed, thanks to having taken apart a Tektronix Phasor printer, which uses a similar vacuum pump and reservoir and valve to clean the print heads.Only thing to add would be a small in line fuel filter, so the vacuum valve does not get clogged, which makes them leak, and these little ones are not terribly amenable to being taken apart to clean the internal parts. Go to auto parts store and ask for the smallest inline fuel filter they have, generally one suitable for a 1966 VW beetle will work, as they did not come with one ex works, and the little dinky inline 6mm one was a common upgrade for them. small filter before the valve, and then get a humongous 6mm Toyota Hilux fuel filter, which also makes a very good vacuum reservoir.With this probably a good addition would be a off delay timer to control the pump. Tap the switch and have the pump running for 30 seconds, so you can have good vacuum all the time, but when you stop the pump only runs for 30 seconds extra. Generally you will just wait 10 seconds after the first tap, then desolder fully.

author: james_s
author_rank: Super Contributor
timestamp: December 19, 2018, 07:36:43 pm
content: You could add a vacuum switch that runs the pump only as needed to pull a vacuum in the line. That would probably increase the lifespan of the pump, and certainly reduce the annoying noise. At that point you might want a small reservoir too, I don't really know.

author: djos
author_rank: Unknown
timestamp: December 19, 2018, 08:07:41 pm
content: Quote from: macboy on December 19, 2018, 04:40:06 pmAgreed, I am considering doing that next year when I return from holiday with the family.

author: djos
author_rank: Unknown
timestamp: December 19, 2018, 08:15:04 pm
content: Quote from: james_s on December 19, 2018, 07:36:43 pmThat's another good idea, I don't thing the reservoir is needed but a run timer is a great idea.

author: james_s
author_rank: Super Contributor
timestamp: December 20, 2018, 01:46:16 am
content: I don't even think it needs a timer, just a vacuum switch that starts the pump when the pressure rises and then shuts it off. It would then automatically respond to triggering the valve.

author: djos
author_rank: Unknown
timestamp: December 20, 2018, 03:16:26 am
content: Quote from: james_s on December 20, 2018, 01:46:16 amThat would certainly work - I must say tho, Im finding it working really well as-is, so I may not bother messing with it for a while.

author: djos
author_rank: Unknown
timestamp: December 20, 2018, 04:58:35 am
content: So one thing that is quite noticeable since the upgrade is how all the solder now forms in a cluster at the back of the tube. Previously the solder sprayed around the whole tube much more evenly. I think this shows the mods are working well.

author: Muttley Snickers
author_rank: Unknown
timestamp: December 20, 2018, 05:11:59 am
content: The solder has always gathered at the rear of the chamber on my machine which hasn't been modified other than the addition of a base plate, increasing the suction would probably cause it to gather there if it wasn't before.

author: djos
author_rank: Unknown
timestamp: December 20, 2018, 05:57:27 am
content: Here's a before shot, imo the amount of spray covers more of the glass and there's a noticeable amount of solder on the spring close to the nozzle end.

author: Southerner
author_rank: Regular Contributor
timestamp: February 23, 2019, 06:48:12 am
content: Do the S993 stand alone desoldering guns work the same way or are they running 110/220vac rather than 12v? I bought a Aoyou 701A++ thinking it would be a great tool but the thing is always plugged and very hard to unplug. I even put in a Hakko chamber but that did not help. When I saw your mod I thought it might be a great addition and replacement for the desoldering gun of the Aoyou 701.Thank you.

author: djos
author_rank: Unknown
timestamp: February 23, 2019, 07:12:12 am
content: Quote from: Southerner on February 23, 2019, 06:48:12 amThe S993 is mains voltage so I wouldnt be keen on modding them myself.

author: Southerner
author_rank: Regular Contributor
timestamp: March 09, 2019, 09:05:16 pm
content: I could not find a ZD917 so I bought a ZD915 that arrived today. Can you tell me if the chamber is the same as a Hakko solder chamber so that the Hakko chamber could be substituted for the stock chamber? Also, will Hakko desoldering tips work in this gun? There is another thread on here for an Aoyou 701A++ and it was recommended that a Hakko chamber be used instead and also the standard (Aoyou) tip had to be machined to accept a Hakko tube. These tips look like they might take the Hakko tube. The reason for doing that was because the Aoyou tips were horrible, at least initially but the Hakko tips were first class.I am waiting for the vacuum switch. I also looked for a 24v version but all of the ebay sellers seemed to only have the 12v version and the 6v and 24v were no longer in stock.

author: Gyro
author_rank: Super Contributor
timestamp: March 09, 2019, 10:00:35 pm
content: I'm really sorry that this probably isn't going to help you, Southerner (although you could try Farnell/Element 14 in the US), but CPC in the UK are selling ZD915 parts really cheaply these days, including glass chambers. I'm not sure if they're trying to clear stock...https://cpc.farnell.com/search?st=zd552Also, filters...https://cpc.farnell.com/duratool/d00759/filter-for-zd-915-pk-5/dp/SD01419?MER=sy-me-pd-mi-acce&st=D00672

author: Southerner
author_rank: Regular Contributor
timestamp: March 09, 2019, 10:41:19 pm
content: Quote from: Gyro on March 09, 2019, 10:00:35 pmElement14 is just a forum here in the USA. Newark shows nothing for a ZD915, ZD917, or the ZD552 that you linked at Farnel UK.Thank you.

author: Southerner
author_rank: Regular Contributor
timestamp: March 15, 2019, 07:12:02 pm
content: Quote from: djos on December 18, 2018, 12:05:28 amIf the gun/station is running at 24 volts why did you use a 12 volt air valve? In checking the current ebay sellers I see none that actually have a 24v valve available to purchase but it seems a bit odd to use a 12v valve in a 24 volt system. What am I missing? Thank you.

author: Gyro
author_rank: Super Contributor
timestamp: March 15, 2019, 08:23:49 pm
content: This thread may suggest caution in pushing the vacuum pump too hard. Just a thought...https://www.eevblog.com/forum/repair/thinking-of-buying-a-zd985-desoldering-station-vacuum-pump-diaphragm-fail/msg2223978/#msg2223978

author: Southerner
author_rank: Regular Contributor
timestamp: March 15, 2019, 08:51:12 pm
content: Quote from: Gyro on March 15, 2019, 08:23:49 pmThe voltage to/for the air valve has nothing to do with how hard the vacuum pump is being pushed. My point is that if there is 24 volts going to that 12 volt valve it might not like it so my question was, why is a 12 volt vacuum switch being used on 24 volts. Most electronics do not take well to over voltage situations and this appears to be such a situation. That is why I am asking why it is being done that way, or am I missing something?

author: Gyro
author_rank: Super Contributor
timestamp: March 15, 2019, 09:02:08 pm
content: Yes, I know that - I was just commenting on whole the idea of pulling too hard a vacuum on the closed line before opening a valve. Those pump diaphragms may be a bit fragile.Sorry, I don't know about the OP's choice of a 12V solenoid.

author: djos
author_rank: Unknown
timestamp: March 15, 2019, 09:28:29 pm
content: Quote from: Southerner on March 15, 2019, 07:12:02 pmIt doesn't, it uses 12v for the pump system (I measured it), the iron side might be 24v but the pump definitely is 12v.

author: djos
author_rank: Unknown
timestamp: March 15, 2019, 09:32:21 pm
content: Quote from: Gyro on March 15, 2019, 08:23:49 pmThat's one of the reasons I added a toggle switch to turn the pump on and off as needed.

author: Southerner
author_rank: Regular Contributor
timestamp: March 15, 2019, 09:33:03 pm
content: Quote from: Gyro on March 15, 2019, 08:23:49 pmI could not find a ZD985 but did just get a ZD915. I am wondering if there is a vacuum pump that is a better replacement for the one in them if the stock pump is not up to the challenge. I did not see anything in the linked thread that had a solution to that. I know that there have been several web pages outlining a DIY vacuum pickup tool for smt parts that used aquarium pumps but I doubt any of those would fit in the ZD985/ZD915 enclosure in place of the stock pump.

author: djos
author_rank: Unknown
timestamp: March 15, 2019, 09:42:20 pm
content: Quote from: Southerner on March 15, 2019, 09:33:03 pmI think the pump is perfectly fine for the job, I've had my station for several years now and it's been very reliable.

author: Gyro
author_rank: Super Contributor
timestamp: March 15, 2019, 09:44:19 pm
content: Quote from: djos on March 15, 2019, 09:32:21 pmI don't want to over dramatise it, it's just a thread that came up after yours that seemed worth linking. It may have been a one-off of course. I'm a cautious soul.

author: Southerner
author_rank: Regular Contributor
timestamp: March 15, 2019, 09:47:11 pm
content: Quote from: djos on March 15, 2019, 09:42:20 pmHow would it hold up to continuous service (continuously on)? I think that is what was being cautioned. If the mod was done to have the pump on all the time then would the pump survive that kind of service. Now it is only on when you pull the trigger. This mod makes it on all the time and a vacuum valve added to open the line when you pull the trigger.

author: djos
author_rank: Unknown
timestamp: March 15, 2019, 09:54:52 pm
content: Quote from: Southerner on March 15, 2019, 09:47:11 pmIn my case it's only continuously on when im using it, otherwise I switch the pump off manually.TBH, I think continually on is actually better for it, stop/start tends to cause more wear and tear to mechanical parts than continuously running them - think of Taxi's, they are always running and can manage 1 Million Kilometers before being replaced but your average private car gets crushed after 250,000 km's.

author: mzzj
author_rank: Super Contributor
timestamp: March 15, 2019, 10:05:40 pm
content: Quote from: beanflying on December 18, 2018, 05:08:00 amI have old fridge compressor as a vacuum pump in my homebrew soldering system (from era before these cheap chinese units, like 20 years ago)Enough internal volume that I can desolder DIP-16 or similar even after I have turned off the vacuum pump. Even tough it probably would run for hours non-stop but it spits some oil out of te exhaust port.OP: great work, I just can't stand those brrrrrrrrrrrrrrrrrrrrrr-brrrrr-brrrrrr-suck-a-little-suck-slowly desoldering stations.that small solenoid valve is nice... I used one that is 10 times the size.

author: Southerner
author_rank: Regular Contributor
timestamp: March 15, 2019, 11:53:59 pm
content: Quote from: mzzj on March 15, 2019, 10:05:40 pmI also have a vacuum pump from a refrigerator but it will not fit in the ZD985 so I would not even consider using it. I am not familiar with smaller vacuum pumps other than aquarium air pumps that can be converted to small vacuum pumps.

author: Southerner
author_rank: Regular Contributor
timestamp: June 01, 2021, 07:30:22 am
content: Does anyone know of a decent replacement for the vacuum pump in the Aoyue 701A++? The one I have is a dismal failure. I ruin more boards trying to desolder a part. My ZD915 is better but it still seems to lack enough vacuum to actually clean out solder around a lead. I am hesitant to buy the Aoyue vacuum pump for the 701 since it does such a poor job now. Does anyone know of a better (more suck) vacuum pump that will fit in these? I tried calling Hakko about the vacuum pump in their 701 (which is what I think the Aoyue 701A++ was cloned from) and the price was something like $300 but not available anyway.Thank you.