Hi,

dl324, If I were to start again, I would have done that

DodgyDave, Can you clarify please, as there are only three connection points on the tip.

Mr Al, I did a bit of light reading. You circuit appears to drive the iron with a linear voltage, looking at this circuit board (see attachment #1) it seems to have Fets, so I imagine it is driven by PWM. I know it switches, using a magnet (external I think) from 24V to 12V when in the holder.

C.

 

I was looking at the pdf in post#1 you uploaded, it shows the pinout of the soldering iron plug, 5 pins, Or is it not the same iron, most weller irons are 24V ac, triac controlled, but dc will work just as good.

 

Ok, then...

The 'cold' readings suggest that each 'device' (i.e. heater and sensor) are common to ground -- Hence R(tip to ring) = 1.9Ω+1.1Ω=3Ω However the 'Hot' readings are inconsistent with this in that we would expect a tip to ring resistance of 6.3Ω+0Ω=6.3Ω ≠5.6Ω) -- A discrepancy of 700mΩ (~11%) is not insignificant!

FWIW I suspect that the discrepancy owes to insufficient test temperature regulation - and (owing to the apparently negative temp coefficient) that the sensor is between tip and ground) -- that said - please don't act upon my latter 'hunch' at this time!

Please double check the 'hot' resistances. -- Additionally, please verify that the resistance readings are independent of polarity (i.e. test them 'each direction')


Best regards and please keep us posted
HP

HP,

See attached video: The video is two halves, GND to large contact, left reading RING, right reading TIP. 1st half positive connections, 2nd half negative connections.

UNABLE TO LOAD VIDEO BEAR WITH ME

C

 

HP,

See attached video: The video is two halves, GND to large contact, left reading RING, right reading TIP. 1st half positive connections, 2nd half negative connections.

UNABLE TO LOAD VIDEO BEAR WITH ME

Please be advised that there's no need for a video --- A table showing the readings with the conditions under which they were taken (i.e. polarity and connections) would be perfectly acceptable/welcome

Best regards
HP

 

Please be advised that there's no need for a video --- A table showing the readings with the conditions under which they were taken (i.e. polarity and connections) would be perfectly acceptable/welcome

Best regards
HP

Please be advised that there's no need for a video --- A table showing the readings with the conditions under which they were taken (i.e. polarity and connections) would be perfectly acceptable/welcome

Best regards
HP

HP,

(Fail to upload a Video possibly a Firefox problem?)

The video is two halves, GND to large contact, left reading RING, right reading TIP. 1st half positive connections, 2nd half negative connections.

Try this:

C.

 

@camerart --- The video isn't working...

Following 15 minutes heat-up -- please record the measurements as follows:

Where "xxx" represents the reading field (any number of digits)

Tip-Com-xxx |i.e. Positive to Tip / Negative To Common|
Com-Tip-xxx |i.e. Positive to Common/ Negative to Tip|

Com-Ring-xxx ......................."Ditto"
Ring-Com-xxx ......................."Ditto"

Tip Ring-xxx ........................."Ditto"
Ring-Tip-xxx ........................."Ditto"

Best regards
HP

 

I was looking at the pdf in post#1 you uploaded, it shows the pinout of the soldering iron plug, 5 pins, Or is it not the same iron, most weller irons are 24V ac, triac controlled, but dc will work just as good.

DD,

The 'soldering pencil' plugs into those connections, and terminates in a 3connection 'jack socket' if you look at the PDF I posted you will see these tips, with a 3connection 'jack plug'

C.

 

Then there must be a Ground common terminal, one will be the heater, the other the thermocouple.

 

Then there must be a Ground common terminal, one will be the heater, the other the thermocouple.

Hi DD,

Agreed, but which one? They both show similarities. HP is analysing the different readings, once I get the info posted.

Can you see the video?

C.

 

Looks like the tip is the heater, the ring must be the thermocouple.

 

Looks like the tip is the heater, the ring must be the thermocouple.

Can you see the video?

C.

 

Yes video clearly..

 

@camerart --- Do you, perchance, possess or have access to an LCR indicator or reactance bridge operational anywhere in the low kHz range (i.e. 1 kHz to 10 kHz)? --- The heater is certain to exhibit greater inductance than the thermistor/thermocouple... (FWIW the upper limit of 10kHz is dictated by the 'raging' parasitic capacitance inherent to such arrangements).

Otherwise - RE: the resistance measurements:

...They both show similarities. HP is analysing the different readings, once I get the info posted.

To that end - please verify that the values have stabilized (within reason) prior to recording them -- While 15 minute's heating should be sufficient, it is generally advisable to take nothing for granted

Best regards
HP

 

Yes video clearly..

Good, now know I can do it ok, ta.

C

 

Good, now know I can do it ok, ta.

C

FWIW -- My difficulty presents as endless 'buffering' --- May be my lousy DSL connection.... again!

Best regards
HP

 

HP[/QUOTE]

@camerart --- Do you, perchance, possess or have access to an LCR indicator or reactance bridge operational anywhere in the low kHz range (i.e. 1 kHz to 10 kHz)? --- The heater is certain to exhibit greater inductance than the thermistor/thermocouple... (FWIW the upper limit of 10kHz is dictated by the 'raging' parasitic capacitance inherent to such arrangements).

Otherwise - RE: the resistance measurements:

To that end - please verify that the values have stabilized (within reason) prior to recording them -- While 15 minute's heating should be sufficient, it is generally advisable to take nothing for granted

Best regards
HP

HP,

I could probably find someone with an LCR indicator or reactance bridge, if absolutely necessary.

Are you able to see the video yet? You should be able to! I was hoping this would show you what you need to know, with a simple set-up. It shows ne connection going negative, then positive as the tip is heated, while the other is the same pos or neg.

C

 

FWIW -- My difficulty presents as endless 'buffering' --- May be my lousy DSL connection.... again!

Best regards
HP

HP,

Ah, I see! I use a program called downloadhelper, where you can download it before watching. (Firefox add on) I also have a slow connection

C.

 

Why dont you put your dvm's on both common and each termial, and stick it in a flame and see which one gives out the millivolts, that will tell you which is the thermocouple.

 

Why dont you put your dvm's on both common and each termial, and stick it in a flame and see which one gives out the millivolts, that will tell you which is the thermocouple.

Hp eliminated thermocouple see #16.

C.

 

Hi,

From your comments and my thoughts, I doubted my readings, so I repeated them. Oooops! Sorry

I tried the thermocouple my test again, and found it does give off mV.

Hot after 15 mins.
GND to RING 4.4mV
GND to TIP o.6mV
Reversed.
GND to RING 4.4mV
GND to TIP 0.6mV

RING to TIP 5.0mV
TIP to RING 5.0mV

Cold
All around zero.

C.