#ZD-917 and clone Power Supplies - Main part of SMP Supply

[pickit2]

This is the main part of the power supply for the Soldering & Desoldering Work Stations
It is a Module marked as 18V power supply.

It is used in models # ZD-917 # 915 # ZD-916 &  maybe other numbers
Also used in D00674 a clone by Duratool.

The main chip seems to blow without damage to other components.
This happened on 4 units in a workshop that have 10 work stations.

[solutions]

You have me curious

Thermal failure or surges?

Any idea?

What do they use for a heatsink?

You may be able to send them into Fairchild for FA

[an007_rld]

Fill the values in "FPS Design Assistant for AN4146" and check if the maximum drain reflected voltage exceed 650V.
Could be the reason why the main IC fail...

[solutions]

aka "no snubber"

[pickit2]

I was not involved in the repair of the units, I just took a copy of the schematic diagram, as I have the same model in my workshop.

I think it has to do with not having a snubber, as in AN-4137 or the problem is in the sync control.
The build quality is very bad, they use silicon heat pads & thermal paste for heatsink which part of the power supply case.

They made the power supply & Iron control on the same pcb, I think it should have been two pcbs.

If I was to try and fix the units to what I would be happy with, I would replace the power supply and make the Iron control as a separate pcb.

snubber

[Elmer]

I read a teardown review of the unit on eevblog discussion, and the guy didn't seem overly enthusiastic about the build quality of these things. So many issues it becomes hard to point out which one to focus on.

[myheadhurts]

I must have an older design Duratool zd-917 .

Mine has a single 50hz transformer for both sides , powered by two opto coupled boards ,each one using a mosfet behind a bridge rectifier to control the ac power to the element. Controlled by two boards with a silabs 8051 for the logic and a holtek driving the display.

It looks like two d000673s in one box.

Nippon - zhongdi make the Duratool models ..they seem aimed/designed to be more hobbyist that professional.

[OrciBorg]

What is the current power source? If it is low power, no need snubber.

[pickit2]

I must have an older design Duratool zd-917 .

Mine has a single 50hz transformer for both sides , powered by two opto coupled boards ,each one using a mosfet behind a bridge rectifier to control the ac power to the element. Controlled by two boards with a silabs 8051 for the logic and a holtek driving the display.

It looks like two d000673s in one box.
Nippon - zhongdi make the Duratool models ..they seem aimed/designed to be more hobbyist that professional.

Yes they replaced the transformer with two SMP modules 240vc to 18v @ 20A (bit optimistic I think) and added the Mosfet circuit to the same pcb.

The front panel and the 8052 control & display are the same.

In use they are very good and take less space than my old Weller DS900 and I use the ZD-917 as its easier to keep clean (maybe I will put the Weller on e-bay) just seen one sell for £82

lol
My old boss just phoned he must be following this topic, and has said I can have 3 of the old 917 units, they only repaired one, plus 5 soldier stations using the same modules.
Bet he don't give me the gun & iron to go with them.