Desoldering station ZD 915 no indications, no heating

[rippergr]

Hello all,
I tried to power on my desoldering station ZD915 today and altough the LCD has power and it's on I don't have any indications on the screen and the gun is not heating at all.
I open it up and I don't see any visual fault anywhere.
Does anyone has any clue what should I check?

[stj]

Re: Desoldering station ZD 915 no indications, no heating

check the module with the display is getting or generating 5v
there's several internal variations, post foto's and i can probably give you schematics

[lotas]

Re: Desoldering station ZD 915 no indications, no heating

Here is a topic similar to your problem.
https://www.iwenzo.de/threads/zd-915...lay-tot.55914/

[sam_sam_sam]

Re: Desoldering station ZD 915 no indications, no heating

Are you saying that the back light is on but the screen is blank if this is case I personally have not run into this issue ( however I would check and see if you have 20 volts or so and you should also have a 5 volt rail as well also check that there is nothing on the controller board is that is heating up because I have seen before that the surface mount capacitors have been an issue before I have had this issue before but in my case it was a non stable gun temperature )

Here is what you need to check
Do you have a temperature on the screen that is for the gun or is it “———“ if you have this then you have an open temperature sensor wire

If you have a temperature reading what is the reading and is the “heat” on the screen ( if the “heat” is not on the screen then ) ****if not then you have an issue with the controller board which ****I have not seen this issue before

Dose your gun get hot even though you have no temperature reading

When you press the suction button does it start the pump if not then you might have a controller board issue or you have a bad wire cable or a bad switch

Or the scr or mosfet issue

You need to post a picture of the screen when powered ON and when you first turn it ON so I can see what version board you have because not all versions behave the same way

I have about 6 to 8 of these desoldering stations and I have several different versions of this device I have repaired them in the past

I hope this helps you get started with troubleshooting this issue with your desoldering station

[rippergr]

Re: Desoldering station ZD 915 no indications, no heating

Are you saying that the back light is on but the screen is blank if this is case I personally have not run into this issue ( however I would check and see if you have 20 volts or so and you should also have a 5 volt rail as well also check that there is nothing on the controller board is that is heating up because I have seen before that the surface mount capacitors have been an issue before I have had this issue before but in my case it was a non stable gun temperature )

Here is what you need to check
Do you have a temperature on the screen that is for the gun or is it “———“ if you have this then you have an open temperature sensor wire

If you have a temperature reading what is the reading and is the “heat” on the screen ( if the “heat” is not on the screen then ) ****if not then you have an issue with the controller board which ****I have not seen this issue before

Dose your gun get hot even though you have no temperature reading

When you press the suction button does it start the pump if not then you might have a controller board issue or you have a bad wire cable or a bad switch

Or the scr or mosfet issue

You need to post a picture of the screen when powered ON and when you first turn it ON so I can see what version board you have because not all versions behave the same way

I have about 6 to 8 of these desoldering stations and I have several different versions of this device I have repaired them in the past

I hope this helps you get started with troubleshooting this issue with your desoldering station

Exactly like that. The backlight is on and I have no indication. Not even when I turn it on.
The gun doesn't heat at all and when I press the button the pump is working.
As you can see in the pictures the desoldering station is as new.
I have used it about 20-30 times.

[stj]

Re: Desoldering station ZD 915 no indications, no heating

check the input and output of the 5v regulator 78L05
also there is a zener diode after the 5v to reduce it to 3v - check that too

[sam_sam_sam]

Re: Desoldering station ZD 915 no indications, no heating

Also there is a 5 volt that is in the switching power supply you need to make sure that you have this 5 volt rail and there is also a 5 volt rail that Stj mentioned in his post above

I do not remember what color wires they are but you easily spot which wires they are if you take off the metal enclosure there is a high wattage resistor and a Zener diode it is in a weird configuration just make sure that you have at least 5 volts if I remember correctly it is the -5 volt rail

Check and see if you have voltage on the micro controller ic chip ( is the one has a lot of pins ) which is on the controller board to find which one it just google it the part number one will be the display ic chip and the other one should be the micro controller ic chip

There is a remote possibility that the display it self is the issue or the display driver ic chip

[stj]

Re: Desoldering station ZD 915 no indications, no heating

if it was the display driver the iron would heat up though

[redwire]

Re: Desoldering station ZD 915 no indications, no heating

I would pull the control board and do a visual inspection.
I see rust? or slag on U5 pad. They swapped in mini-melfs for DA1, DA2 but need a huge blob of solder to reach now. It's an ancient chinese trick to use huge PCB footprints and put in way small components, but the solder doesn't always stretch. Like R2, is it soldered on the one end?
Some soldering is suspect.
Check the PSU voltages supplied to the board like 5V and not sure where the 24V heater switch (mosfet) is located.

[stj]

Re: Desoldering station ZD 915 no indications, no heating

i think the heater switching is in the psu

[sam_sam_sam]

Re: Desoldering station ZD 915 no indications, no heating

not sure where the 24V heater switch (mosfet) is located.

The location is one of two ic chips that has three pins I do not remember if the one on the left side or the one in the middle

[sam_sam_sam]

Re: Desoldering station ZD 915 no indications, no heating

i think the heater switching is in the psu

It is however it gets the turn ON signal from the microcontroller on the controller board

The question is does the vacuum pump function when the trigger switch is pushed if not then something is wrong with the switching power supply or bad wiring or bad switch

[stj]

Re: Desoldering station ZD 915 no indications, no heating

pump runs - re-read the thread

[rippergr]

Re: Desoldering station ZD 915 no indications, no heating

The voltage in 78L05 is 5v and 14,5.
In Zener Z1 is 3,3v
I have attached a more close picture of the board.

[sam_sam_sam]

Re: Desoldering station ZD 915 no indications, no heating

The voltage in 78L05 is 5v and 14,5.
In Zener Z1 is 3,3v
I have attached a more close picture of the board.

Look at the soldering joints that are circled in red

[rippergr]

Re: Desoldering station ZD 915 no indications, no heating

Look at the soldering joints that are circled in red

I resolder all the joints but nothing changed

[rippergr]

Re: Desoldering station ZD 915 no indications, no heating

I have changed the Voltage regulator 78L05 and TL431A regulator but I still have the same problem.