Author Topic: Stahl Soldering Station  (Read 21716 times)

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Offline picandmix

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Re: Stahl Soldering Station
« Reply #25 on: February 19, 2015, 10:21:17 am »
Values added, let me know if anything is wrong.
Did spot an error on R1 and R2 labeling , was R2 and R13.

Have specified all 1% resistors as those types are so cheap its not worth getting both 5% and 1%.

edit
Since posting the above, now just looked at your resistor values and what I can see from your original pictures.
Not easy to be sure so of some of the resistor colour bands  eg , red or orange, but I read 3 different from the values you give.
Have you measured in circuit or read off the colour codes  or both ?

R5 I read as 1.2k you say 13k
R8                1.2k  you  say 1.3k
R19              1k    you say  10k
« Last Edit: February 19, 2015, 05:09:24 pm by picandmix »
 

Offline jobogTopic starter

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Re: Stahl Soldering Station
« Reply #26 on: February 20, 2015, 03:01:32 am »
Your latest has R1 and R2 reversed.  R1 is 52 ohm and is connected from the diode D1 to pin 4 of the 555.  R2 is 300 ohm and is connected from pin 2 of the connector to diode D2.

R5 is 1.2K
R8 is 1.2K
R19 is Brown, Black, Orange and measures 10K
 

Offline picandmix

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Re: Stahl Soldering Station
« Reply #27 on: February 20, 2015, 10:06:25 am »
These should be right then... ;D
Did you see your PM inbox ?
 

Offline jobogTopic starter

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Re: Stahl Soldering Station
« Reply #28 on: February 21, 2015, 12:01:05 am »
Still one minor problem.  R1 is the large 3W resistor.  Other than that it looks right.

I spent $1.50, replaced the 4 electrolytics and the zener and this thing is now working.  Still don't know how it works but, Hurrah!!!
 

Offline picandmix

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Re: Stahl Soldering Station
« Reply #29 on: February 21, 2015, 10:12:11 am »
Should be right   :)

 

Offline paiusgeorge

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Re: Stahl Soldering Station
« Reply #30 on: November 22, 2015, 04:44:34 pm »
Hello guys. Please...can you help me ? Can you write what part did you change exactly ? Because i read 10 times the conversation but i did't understand in the final which part did you change... i changed the zener,the r3,the r20...but r20 keeps burning. Thank you very much.
 

Offline Deathwish

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Re: Stahl Soldering Station
« Reply #31 on: November 22, 2015, 05:13:40 pm »
Hello guys. Please...can you help me ? Can you write what part did you change exactly ? Because i read 10 times the conversation but i did't understand in the final which part did you change... i changed the zener,the r3,the r20...but r20 keeps burning. Thank you very much.

the 4 electrolytic capacitors
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Offline jobogTopic starter

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Re: Stahl Soldering Station
« Reply #32 on: November 23, 2015, 03:09:49 am »
Yes, the 4 electrolytics and the zener.  Replaced the 2 burnt resistors.
 

Offline paiusgeorge

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Re: Stahl Soldering Station
« Reply #33 on: November 24, 2015, 03:23:19 pm »
hello dear friends. My english is not that good, and i'm a beginner in electronics,and i think that i changed the wrong parts ( r3,r20,zener and bt136),and it still not work...the r20 is burning .
 Can you please make me a list with the 4 electrolytics that you changed ( for example R1 , R3, R20 etc ) what zener and what you put in that place for replacement( what value has new parts) , because i think that you put a bigger electrolytics for example on r3 i put 33 ohm with 5 w, instead of 33 ohm and 3w.
thank you so much.
 

Offline ross57

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Re: Stahl Soldering Station
« Reply #34 on: February 17, 2016, 11:39:08 am »
Hello to the forum mates,
I have found this thread very helpful since I'm fixing my Velleman VTSSC50N (ZD-919-2) soldering station.
Thank you all for the very useful tips and pcb.
As my contribution, here attached is the schematic received directly form the Velleman Customer Support.
My station had the R3 (0.33 Ohm) resistor and the BT 136 triac burned because was powered with the stylus NOT attached.
An unacceptable lack of protection.
It would be interesting if some expert would give directions to avoid this in the future (opto coupler?), as also to add a green led that lights when the set temperature has been reached (even though I do know that my station has NOT a real tip temperature control since the stylus has only the heater leads).

« Last Edit: February 17, 2016, 12:48:56 pm by ross57 »
 

Offline SkyMaster

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Re: Stahl Soldering Station
« Reply #35 on: February 18, 2016, 10:29:05 pm »
I have purchased a new station.  I got the Weller WES51.  Now wish I had bought the Hakko for the same money.

The Weller station works just fine but, as it turns out, I could have bought the Hakko with the digital readout for the same money.  I think I paid $119.00 for the Weller with 5 additional tips.  I'm finding the digital Hakko for around $90.00 with one tip.  The Hakko also has a ceramic heating element while the Weller is Nichrome wire.  All the reviews I'm reading now, after it's too late, prefer the Hakko.

Jobog,

I have both, so I can compare.

I have a Weller WES50 (made in USA, 2001 vintage) and a Hakko FX-888D (bought recently).

WES50:
The soldering pencil on the WES50 (looks identical to the current one) is bit thinner than the one on the Hakko.
The tips for the Weller sell for about half the price of the Hakko tip.
The analog temperature control of the Weller is nicer to use than the digital control of the Hakko FX-888D.

FX-888D
The user interface of the Hakko FX-888D, with its two buttons, is awful (disgusting would also be an appropriate word).
The power switch on the side is less convenient than the power switch on the front of the Weller.
The brass coil compartment built into the pen holder is a nice feature.

My conclusion is that you have no reason to regret buying the Weller WES51  ;)
 

Offline jobogTopic starter

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Re: Stahl Soldering Station
« Reply #36 on: February 19, 2016, 02:56:12 am »
I have purchased a new station.  I got the Weller WES51.  Now wish I had bought the Hakko for the same money.

The Weller station works just fine but, as it turns out, I could have bought the Hakko with the digital readout for the same money.  I think I paid $119.00 for the Weller with 5 additional tips.  I'm finding the digital Hakko for around $90.00 with one tip.  The Hakko also has a ceramic heating element while the Weller is Nichrome wire.  All the reviews I'm reading now, after it's too late, prefer the Hakko.

Jobog,

I have both, so I can compare.

I have a Weller WES50 (made in USA, 2001 vintage) and a Hakko FX-888D (bought recently).

WES50:
The soldering pencil on the WES50 (looks identical to the current one) is bit thinner than the one on the Hakko.
The tips for the Weller sell for about half the price of the Hakko tip.
The analog temperature control of the Weller is nicer to use than the digital control of the Hakko FX-888D.

FX-888D
The user interface of the Hakko FX-888D, with its two buttons, is awful (disgusting would also be an appropriate word).
The power switch on the side is less convenient than the power switch on the front of the Weller.
The brass coil compartment built into the pen holder is a nice feature.

My conclusion is that you have no reason to regret buying the Weller WES51  ;)

Thanks for the comparison.  After using the Weller for awhile now I really like it.  At the time I thought the digital readout might be nice but no problems with the dial on the Weller.  Thanks again.
 

Offline romdos

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Re: Stahl Soldering Station
« Reply #37 on: March 09, 2016, 05:25:56 am »
Hi,
I know this is a year later, but thankfully I found this forum and thread since I recently had the same problem as the OP, but I noticed mine also burnt up the transistor there.  Do you have a value for that?  I didn't see that one listed in your posting.  All identifying markings were destroyed from the heat, so I can't ID it.


R1  52ohm, 5%, 3W
R2  300ohm 5%
R3  .33ohm 5% wirewound
R4  15K 1%
R5  13K 5%
R6  200K 1%
R7  3.3K 5%
R8  1.3K 5%
R9  51K 5%
R10  530K 1%
R11  100K 5%
R12  2K 1%
No R13
R14  130K 5%
R15  1.5K 1%
R16  5.1K 5%
No R17
R18  15K 5%
R19  10K 5%
R20  200ohm 5%
W2  75K 1%
Variable resistor  1.2K full range, linear
The 4 diodes are N4007's
The 2 small caps are .1uF
C4  47uF, 25V
C5  330uF, 25V

I think I've included everything here.  Thanks again.
Joe
[/quote]
 

Offline romdos

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Re: Stahl Soldering Station
« Reply #38 on: March 10, 2016, 02:35:44 am »
Okay, I will replace the zener as you recommend.  Thanks again for all the work you have done on this.  I can't edit your schematic or I would add the values for the components myself.  If you are up for it here are all the missing values.

The board is a ZD 919-2 which seems to be a pretty common Chinese board for cheap soldering stations.

R1  52ohm, 5%, 3W
R2  300ohm 5%
R3  .33ohm 5% wirewound
R4  15K 1%
R5  13K 5%
R6  200K 1%
R7  3.3K 5%
R8  1.3K 5%
R9  51K 5%
R10  530K 1%
R11  100K 5%
R12  2K 1%
No R13
R14  130K 5%
R15  1.5K 1%
R16  5.1K 5%
No R17
R18  15K 5%
R19  10K 5%
R20  200ohm 5%
W2  75K 1%
Variable resistor  1.2K full range, linear
The 4 diodes are N4007's
The 2 small caps are .1uF
C4  47uF, 25V
C5  330uF, 25V

I think I've included everything here.  Thanks again.
Joe
 

Offline jobogTopic starter

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Re: Stahl Soldering Station
« Reply #39 on: March 21, 2016, 12:21:12 am »
Hi,
I know this is a year later, but thankfully I found this forum and thread since I recently had the same problem as the OP, but I noticed mine also burnt up the transistor there.  Do you have a value for that?  I didn't see that one listed in your posting.  All identifying markings were destroyed from the heat, so I can't ID it.


R1  52ohm, 5%, 3W
R2  300ohm 5%
R3  .33ohm 5% wirewound
R4  15K 1%
R5  13K 5%
R6  200K 1%
R7  3.3K 5%
R8  1.3K 5%
R9  51K 5%
R10  530K 1%
R11  100K 5%
R12  2K 1%
No R13
R14  130K 5%
R15  1.5K 1%
R16  5.1K 5%
No R17
R18  15K 5%
R19  10K 5%
R20  200ohm 5%
W2  75K 1%
Variable resistor  1.2K full range, linear
The 4 diodes are N4007's
The 2 small caps are .1uF
C4  47uF, 25V
C5  330uF, 25V

I think I've included everything here.  Thanks again.
Joe
[/quote]
Sorry this is so late but I just saw your question about the transistor.  It was replaced with a C9013.
 

Offline Shredhead

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Re: Stahl Soldering Station
« Reply #40 on: June 08, 2016, 04:31:49 am »
Assume from the lack of a sensor in the iron then you have no true temperature control.

The lower form of 'controlled' stations just use what is basically a pot controlling the flow though the triac, like a light dimmer, which does produce a basic temperature control.

I have this Stahl Station and it must use some kind of feedback to sense the load.  My handle's element failed after about 2 years of moderate use so I hooked up different kinds of elements and dummy loads to the station and scoped the output of the station.  I found that it reacts much differently with each different load attached. 

Stahl is apparently a product of Parts Express and they don't sell replacement elements for it.  I can't find any element that will fit the handle anywhere online in the US.  I bought a 936 clone handle to rig up to it leaving the thermocouple wires not connected and no matter what the setting of the temp on the station, it will slowly ramp up by itself until the power is on to the element nonstop. 

This Stahl TCSS station is a disposable pile of dung.  Everyone out there should avoid it. 
 

Offline Feliciano

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Re: Stahl Soldering Station
« Reply #41 on: October 09, 2018, 02:25:29 am »
Been a long time reader, now I want to give back a little.

If somebody's still insterested in this piece of cheap hardware as I do, I can tell in fact it's cheap, and hence it's electronics it's also cheap, with several corners cutted.

I studied the schematics (which has a few errors like a diode reversed, a couple of missing components, and two capacitors interchanged, and I've also seen others with other Q's). Besides that, it can be reinforced adding a snubber to the triac and optionally other protection to the transformer, to avoid the transients, like a possible connection/disconnection of the handle during operation (not recommended), an eventual burnout of it, etc. I'll do those modifications myself one of these days.

On the other hand it's feedback is rather minimal/indirect, sensing the voltage over R3, which is influenced by the presence of the handle, and up to some extent, its temperature.
« Last Edit: October 18, 2018, 01:11:29 am by Feliciano »
 

Offline Feliciano

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Re: Stahl Soldering Station
« Reply #42 on: January 05, 2019, 04:38:36 am »
I designed/added the snubbers, an additional filter for V+ and started to use it.

For my dissapointment, after half an hour of continous use at low temp, R3 burnt out, taking the transistor with it (at least my modifications seems to salvaged the triac and ICs). So I replaced the damaged components with more resiliant ones, improved the heat disipation, and used my oscilloscope to find out the Q of the main components. I confirmed what my simulations showed, that this design seems clever in principle, but it's too sensitive to component's values.

I'll use it again, and update this post if find something relevant to add.
« Last Edit: February 03, 2019, 09:07:19 pm by Feliciano »
 

Offline NGY

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Re: Stahl Soldering Station
« Reply #43 on: July 17, 2022, 10:09:23 am »
I understand this is a VERY old topic. Nevertheless, may I post my finding here, as I feel it relevant, and documenting the technical side here could probably be interesting for future readers too. These soldering stations are still being manufactured and sold.

I recently bought a disfunctional Fahrenheit 28003 soldering station (with the same ZD-919-2 board shown above), with its belonging iron, told as the defective part. The station looked neat and clean, inside out. The iron indeed shown an open circuit. Before purchasing a new heater, I wanted to understand how this control circuit worked - this is how I got here.

I opened the faulty heater element to get an idea, what is going on with this simple two-wire iron, that has to do with some kind of reasonable temperature control. Then I found the "trick": the iron's heater element consists of the actual heater coil, and a sort of thermocouple, in series with the coil (see my photos below).

So then yes, there is a kind of temperature control: the control circuit is watching the current flowing through the heater element, via the voltage across the 0R33 resistor amplified by opamp-1, then opamp-2 compares it to the voltage set by the pot for the required iron temperature, and triggers the triac via the 555 timer. Simple as it gets.

In my case, this thermocouple was broken. I redid the thermocouple joint - just a makeshift thing to get the iron working for the time of some quick experiments. Based on my very rough measurements, the resistance of the heater element (coil+thermocouple) varied like this: at room temperature (25 °C) ~3 Ohms, then at 100/200/300/400 °C approx. 20/27/35/42 Ohms respectively - in this practical range looked actually fairly linear.

Regarding the burnt 0R33 resistor (seen this issue also on other forums): I guess it happens when that "hidden" thermocouple fails and the control circuit keeps triggering the triac.

I truly can't believe that this resistor could burn when the soldering station is switched on without the iron attached. More important though is to use it with its own iron exclusively (with this special heater element), to keep the control circuit working in its appropriate range.

(One last commment: to improve the stability of the temperature control, I added a zener diode in the positive voltage rail circuit too, by simply soldering it in parallel to the elco's leads.)
 


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