Soldering iron standards

[akis]

A year ago I bought this soldering station from Maplin (in the UK) http://www.maplin.co.uk/p/60w-professional-lcd-solder-station-with-esd-protection-a55kj

I noticed the soldering iron connects to the base by means of a 5-pin BNC plug. I assumed there is a "soldering iron standard" and bought two replacement irons on ebay with same plug, one third of the price that Maplin sell their replacement iron.

Many months later, I tried to use one of these but the station rejects them, I get some error or something on the digital display.

So is there a "standard" or have I been fooled?

[KJDS]

There is no standard that I am aware of.

[tautech]

Had a similar problem a couple of years ago, might be a simple fix.
The pinouts were different and be sure to check the temperature control.

[Wh1sper]

Beside  of standard layout , even there is no standard for measurement the temperature.
It could be using the heating device itself as thermocouple or a separate thermocouple or may be other variants.
 

[akis]

Next question:

Applying a temperature meter on the conical tip, I measure highest temperature in the bottom or middle of the cone, and about 100C difference to the tiny tip. This became way more pronounced when I switched to lead free solder that melts at much higher temperatures, it would only melt in the middle not at the tip, and further more, when soldering the melted lead blob would be "pulled" upwards to the middle of the tip where it was hotter. The tip size is about 20mm length (the height of the cone) with about 8mm being the "business" end where solder can melt. It seems the highest temperature is near the base of the cone than the tip.

I also think there is a large delay and difference between tip temperature and element temperature .

Any ideas ?

[akis]

I opened them up and took two pictures. The original Maplin one only uses 3 wires out of the 5 possible. I presume it is earth, and V+ and V- for the heater element *including* temperature reading. Somehow. The replacement seems to use all 5 wires and does have what appears to be a thermocouple on the extra two wires. So in my opinion the cheap replacement iron is better than the much more expensive Maplin one.

[KJDS]

There's been a lot of discussion on here over the years about soldering irons, and the conclusion always is that if you can afford it, then JBC, Metcal, Ersa or Pace are worth the money. Hakko in the US is a good value halfway house and everything else is a compromise to far for any complex soldering.

[saturation]

There is no standard for how the stations are made, e.g. plug compatibility or tips, but there are specification standards.  The IPC sets them internationally but compliance is not mandatory.

 http://www.ipc.org/ContentPage.aspx?pageid=J-STD-001

https://www.eevblog.com/forum/reviews/developing-a-quantitative-approach-to-evaluating-soldering-stations/msg63012/#msg63012

[sleemanj]

If it's a typical 900 series (936) handle, then it will have one of 2 ceramic elements which you can get on ebay, "A1322" or "A1321".

You can tell them apart by measuring the resistances...

A1321 thermocouple resistance: ~60 Ohms
A1322 thermocouple resistance: ~4 Ohms

A1321 heater resistance: ~8 Ohms
A1322 heater resistance: ~18 Ohms

Physically they are the same from memory and either should fit into any of the knock-off handles. 

[akis]

MY soldering station, it seems, is not compatible with irons that contain a separate thermocouple - it expects to read the temperature off of the heating element, somehow.

[amyk]

That looks like a rebranded Atten AT938D; look for replacement parts using that model number.

[dannyf]

have I been fooled?

You haven't been fooled. You mis-assumed.

[dannyf]

It seems the highest temperature is near the base of the cone than the tip.

Disassemble the tip and you will see why.

[akis]

The heating element fits into the tip and yes the pointy bit is the farthest from the heating element so I presume this is the problem. We are only talking about a few mm, but it makes a difference when you try to solder and you see the solder defying gravity and flowing upwards and away from the PCB onto the middle section of the tip.