18VDC PSU has dropped to 10v - ZD-915 desoldering station

[hdtvman]

Re: 18VDC PSU has dropped to 10v - ZD-915 desoldering station

The problem look like you do not have your soldering hot enough to make good looking joints because some of them look like crap at least with the photo that you posted

Good tip! they did come pretty crappy looking to start with (those were the top pictures) - I'll crank it up and reflow again - cant hurt... They also let a lot of flux on the board which I have now cleaned up for the most part ... unfortunately it didn't help...

[hdtvman]

Re: 18VDC PSU has dropped to 10v - ZD-915 desoldering station

Not in this model it the one that has transformer that has several winding on it with a small board with a bridge rectifier and some capacitors and a triac ( but this version has it own issues )

I am wondering if you have version one when they first come it with the switching power supply version

There is a way tell which version you have the first version ( if you have this version this nothing but problems) when you power it on with the trigger button pushed does the pump start right away or does it wait until it has finished booting I had one of this version and I modified the switching power supply to work off of a battery but I will not go into in this post but I do have a post about it

If you have the revised version it wait until it is finished booting before you can run the vacuum pump

This version is a lot better and it holds up very well under heavy use

There is a solution to this type of switching power supply but have do some modified of this switching power supply board and it not easy to do but can be done

If I remember correctly the trigger on mine does not work until it finishes booting. The board says rev 3. maybe they broke something from the improved version 2 :-)

[sam_sam_sam]

Re: 18VDC PSU has dropped to 10v - ZD-915 desoldering station

[ they are not for sale ] —>

I do have some replacement controller but I do not remember what revision they are but I know that they are not the first version of it though

( unfortunately the eBay seller I bought them from dose not carry them anymore )



But the reason I mentioned it was because I have had to replace a couple of them because of controller failure that was not repairable or I could not figure out how it failed the other failure is the vacuum pump becomes weak and does not have enough power to job anymore I have been using for several years now and I have the feeling that vacuum has become weak and nearly at the end of it life

Might be time to buy another sometime in future

When you have where the soldering joints are not looking good even though you reflow them just remove the solder and reapply the solder again and should make a better joint

[sam_sam_sam]

Re: 18VDC PSU has dropped to 10v - ZD-915 desoldering station

One note

The replacement controllers that I have to do not have a version number but the model number is
“ *** YD6”

I have some that have issues YD1 and YD2

One of them does not control the temperature correctly anymore ( over shooting issues ) and it not the gun and the back light does not work anymore

The other one the back little light does not work anymore

I have two of them that the vacuum pump are very weak and not useable anymore but I keep them for if the motor on one of them quits working I have the part to fix it again

[sam_sam_sam]

Re: 18VDC PSU has dropped to 10v - ZD-915 desoldering station

The version of the controller version is number 3 ( shows when booting up )

I also have version number 2 and that one has some issues but I cannot remember exactly what the issue was with them because my replacement ones are version 3

I did confirm that the problem I was having with the vacuum not being enough was correct I replaced it with one that only has a few hours on it

So now I have three of them that have vacuum pump issues with not having enough power to suction to pull the solder from the joint it only doing it half way right but not clearing the holes

Still using the same gun and tip

[hdtvman]

Re: 18VDC PSU has dropped to 10v - ZD-915 desoldering station

wow - that quite a collection of 'em. At least thats a great collection of spare parts. I did read somewhere that these units do not clear properly and that the buildup accumulates on the suction tube internally making the performance worse gradually.
I did hear from the vendor today - just a short message saying they are sending a package and my UPS tracking number is xxxx. (not quite sure what they are sending, maybe a new replacement unit. that would be awesome...). They did not mention RMA or sending defective unit back. So I'll see in a day or so when the mystery package arrives. If they did send a new unit, then I will be quite happy, since they could have stuck it to me since I was slightly over the 30 days. But we shall see. It might still be taking a trip across the state :-)
Good tips on the solder removal and flow, there's only one catch. removal of the solder is going to be particularly difficult without the desoldering unit (actually I do have an old Velleman 30 watt manual sucker, but it's not that effective :-)
One interesting thing is I noticed that the price of the ZD915 from this vendor on Ebay, doubled since I bought my unit... not sure why... There are now a few vendors on Amazon also carrying it. (unless its the same vendor wit different business names...) which often happens wit Amazon. I had to remove a socket today with the Velleman and what PIA - I miss the ZD915 .

[hdtvman]

Re: 18VDC PSU has dropped to 10v - ZD-915 desoldering station

update: replacement unit has not arrived yet... but the tracking indicates the same weight package as the first unit (7.5 lbs) so it appears to be a complete replacement (keeping fingers crossed).

Ordered some FSCQ1265RT just in case...

[sam_sam_sam]

Re: 18VDC PSU has dropped to 10v - ZD-915 desoldering station

When you get the “ FSCQ1265RT ” and installed it use a incandescent light bulb in series with the with fuse remove when powering it up after installing the new part the light bulb should at least a 100 watt and should only dim once the capacitors get charged if it real bright and does not dim ( you have another issue )

( This is with out the gun not hooked up )

If the light bulb is only dim then hook up the gun and you might have to use a 200 watt bulb instead of the 100 watt for this test you should see the temperature climb if so then push the trigger button and you should hear the pump running now the light bulb might very bright which would be fine at this point ( one note if it happens to turn off and reboot use a 300 watt bulb or use 3 100 watt bulbs in parallel and do the same test again )

If everything goes well with this test then reinstall the fuse and then put power again and see if everything is ok again

Now if I were doing this repair I would replace all the capacitors except the main filtering capacitor
and should be good to go again

However if this ic chip failure happens again in a very short time period then you have some type of issue that need to be investigated further

One other note if you have the tube that the solder goes through to the collection tube and you can not clear it take a 1/16” dill bit and carefully remove the build up until you can put the cleaning wire through the the tube again

This problem happens because of to much flux sucked up the tube ( if your filter gets very dirty looking peal off the first layer of it and reuse it again this helps to keep the flux built up to a minimum )

One final note be sure to remove the shipping bolts if it has any before powering the new unit if you did not remove it from the first unit that you have you need to remove them as well if it has them

If your tip becomes uneven and you can not suck up very little solder then if you have a dermal tool with a cutoff disk take the tip and remove the part that has made it uneven and make the the tip flat again and should be good to go again this happens because using the tip to straighten the component leads which should be avoided if you do not want to resurface the tip all the time ( normally you do not use the side of cutoff disk this way however it is the easiest way to resurface the tip to make it flat again just be careful not to use to much pressure on the disk to break it let the tool do the work light pressure works best )


I find that if you set the temperature at 775* F and you do not leave the tip on the board for more than a second or so this works for me the best most of the time however if you see that the circuit traces ( or that the board is turning brown or black) are being lifted then drop the temperature 100* F for this board and once you are done with this board then set the temperature back to the 775* F
I hope this helps

[hdtvman]

Re: 18VDC PSU has dropped to 10v - ZD-915 desoldering station

Fantastic Tips!
The switching ICs haven't arrived yet but I will follow your bulb procedure to prevent it from going full heat and burning out the element.

The new unit arrived yesterday and indeed it is a complete replacement unit and it does work. I have to say that the company I ordered from on Ebay (I believe was AnestyDirect) were great to deal with. I did open up first to be sure nothing was amiss and it all is good (so far...). I turned it on to the default 160C first and let it fully warm up and then raised it to a conservative 385 (725 F) was able to use it for about 15 or 20 min with no issues just to test and recap a VIC-20 and it worked quite well and no damage to the board or traces. BTW, It is identical in revision (U3 on powerup) to the failed unit. I also tried my original gun and it worked well with it, so no issues there. I did notice that the both units by design put out 18+v to a rear fan (labeled 12v ! ) and the heater..... and there are some YouTube posts about that, at some point the fans used to be 24V and I may replace mine with 24V 50x50x15 model. Fortunately it is loud enough that I would know if they failed prematurely due to the over voltage.

Yes, great tip, I actually avoid putting any side pressure on the tip (or doing the circular motion around the pin) as I heard that this is a weakness of this unit with the black plastic behind the element breaking/deforming too easily when very hot. Generally I'll suck up the solder initially, use a small screwdriver to straighten tip and then suck up any more solder remains.

I'll post an update when the ICs come in !

[sam_sam_sam]

Re: 18VDC PSU has dropped to 10v - ZD-915 desoldering station

There is no problem going in a circular motion as long as you do not put a lot of side pressure in fact it works better if you use a circular motion it clear the soldering joints better when doing it than not doing

One note use the right size tip for the components that you are trying to remove from the board sometimes it is more important if the soldering joint pads are very small to being with do not put a lot down pressure on the board when you have very small soldering join pads or you lift the pad off of the board

One other note if you have to this unit with the temperature at maximum setting do not leave it at this for long periods of time because it shortens the life of the gun

One final note if you have soldering ground plain pad holes you will find it work very do doing soldering in component when doing switching power supply I do this quite often

[stj]

Re: 18VDC PSU has dropped to 10v - ZD-915 desoldering station

it isnt 18v to the fan, because it goes through a couple of wirewound resistors.
the fan is shit though.

i replaced mine with a sunon maglev fan and a 9v buck convertor

[hdtvman]

Re: 18VDC PSU has dropped to 10v - ZD-915 desoldering station

Great tips!
Still waiting for the CQ1265RTs - got about 5 of them just in case they will be needed :-)

[hdtvman]

Re: 18VDC PSU has dropped to 10v - ZD-915 desoldering station

it isnt 18v to the fan, because it goes through a couple of wirewound resistors.
the fan is shit though.

i replaced mine with a sunon maglev fan and a 9v buck convertor

This model number a good choice ?

ME50152V1-000C-A99

[stj]

Re: 18VDC PSU has dropped to 10v - ZD-915 desoldering station

i will try to find what i used.

[sam_sam_sam]

Re: 18VDC PSU has dropped to 10v - ZD-915 desoldering station

the other failure is the vacuum pump becomes weak and does not have enough power to job anymore I have been using for several years now and I have the feeling that vacuum has become weak and nearly at the end of it life

Might be time to buy another sometime in future

I had time and nothing else better to do so I took the vacuum pump apart and this what I found

I have found what the problem with the vacuum pumps are they are as follows

One
these are serviceable to some existence but you have to look closely for cracking on the pump rubber parts

Two

Carefully take the pump housing apart

( has two screws that hold the valve body to pump frame and one screw that hold the pump valve assembly valve port together )

and look at the

( die frame rubber looks very similar to a steal reed valve ) there was this crusty yellow material on the valve also vacuum cup that hook to valve body has a metal flat washer that was rust on the side that push’s on the rubber cup to the connecting rod

After cleaning these parts and flipping the washer on the shiny side ( down in stead of being up ) I have a lot more vacuum and I only have done one side so far

[hdtvman]

Re: 18VDC PSU has dropped to 10v - ZD-915 desoldering station

I want to give a big shout out to this forum and especially to sam_sam_sam for all the great advice! I am happy to announce that the bad ZD-915 is now fixed. Wound up checking the caps - they were OK then I replaced the CQ1265RT and she came back to life! Doesn't overrun the temperature set and appears to be working well. I have it back on the bench and will give it a work out this week to see how it goes. There was no evidence of cracking or burning on the original CQ1265RT. I guess it just failed internally.

[sam_sam_sam]

Re: 18VDC PSU has dropped to 10v - ZD-915 desoldering station

I am glad you got it back up and running again
I would recommend that for a while I would not leave the room that you have it and leave it running by it self

Just in case it decides to take a shit again I personally have had this happen to one of the them before

[stj]

Re: 18VDC PSU has dropped to 10v - ZD-915 desoldering station

now another tip.
dont spend money on filter discs

but an A4 size sheet 0f 3mm ceramic wool gasket.
like this: https://www.ebay.co.uk/itm/223837165275

and a leather punch.
like this: https://www.aliexpress.com/item/32826370605.html

[hdtvman]

Re: 18VDC PSU has dropped to 10v - ZD-915 desoldering station

I am glad you got it back up and running again
I would recommend that for a while I would not leave the room that you have it and leave it running by it self

Just in case it decides to take a shit again I personally have had this happen to one of the them before

Definitely, I have my suspicious eye on this one... :-)

[hdtvman]

Re: 18VDC PSU has dropped to 10v - ZD-915 desoldering station

now another tip.
dont spend money on filter discs

but an A4 size sheet 0f 3mm ceramic wool gasket.
like this: https://www.ebay.co.uk/itm/223837165275

and a leather punch.
like this: https://www.aliexpress.com/item/32826370605.html

Great idea.