Hakko soldering iron - UK Vintage Radio Repair and Restoration Discussion Forum

colebrooker · 28th Apr 2017, 12:23 pm

Hello, I have recently acquired an old Hakko iron, probably 1980's, model number 3?27. Initialy it worked but now the display shows eee and no heat.
There are 5 pins to the iron from the body. What I am looking for is a circuit diagram. It has a number pad to set temperatures with an R and S pads. I have only been able to use a preset at 350 c. Any ideas on this please?
David

MrBungle · 28th Apr 2017, 2:29 pm

I've had hakko irons in the distant past. Usually means the thermistor is gone. You need need to dismantle the hand piece and replace the heating element. You can check the element with a multimeter. There should be 4 wires coming out of the element. Two will be near zero ohms and two will be non zero ohms. If that isn't the case then the element is gone.

Bazz4CQJ · 28th Apr 2017, 3:54 pm

I think Hakko may also have been sold as the AOYUE brand, so if you search Google for them, you may find relevant info.

B

evingar · 28th Apr 2017, 4:17 pm

Quote:

Originally Posted by Bazz4CQJ

I think Hakko may also have been sold as the AOYUE brand, so if you search Google for them, you may find relevant info.

B

My understating is the Chinese AOYUE (no idea how the hell you pronounce it, too many vowels for my liking !!) are copying some Hakko equipment.

https://www.hakko.com/english/

http://www.aoyue.com/en/about/

Let me be clear, I don't think AOYUE are pretending their equipment is Hakko, I bought one of their (AOYUE) hot air rework stations for about £60 and it worked well enough for a year or so before it went bang big time - you get what you pay for - it served its purpose and if I could be bothered, cheap spares are available for it.

MrBungle · 28th Apr 2017, 4:39 pm

Agree. I had an Aoyue 936. Total junk. Don't go near it. Hand piece fell to bits 6 times a day.

colebrooker · 28th Apr 2017, 5:45 pm

Thanks, I do only get a reading between 2 wires, so it looks like the hand piece is to be investigated.

MrBungle · 28th Apr 2017, 6:33 pm

If this is your only soldering iron be aware you need another one to fix it...

Bazz4CQJ · 28th Apr 2017, 11:52 pm

Quote:

Originally Posted by MrBungle

Agree. I had an Aoyue 936. Total junk. Don't go near it. Hand piece fell to bits 6 times a day.

Well, that's pretty whacky because I bought an Aoyue 937 about 6 or 7 years ago and I'm totally satisfied with it. While it certainly has been built to a budget, I have had no problems with it. I bought a bag full of different bits with it and a spare element, but the latter sits unused.

Quite how your hand piece could fall apart 6 times a day may give us a pointer as to where the problem lay

.

B

MrBungle · 29th Apr 2017, 1:14 am

937 is the digital one which is far nicer. Control loop on the 936 analogue unit is dodgy.

The handle on the iron fell to bits because they shipped the wrong part with it. It took me a year to work that out. Got angry and bought a Weller TCP in the end.

hysteresis · 29th Apr 2017, 12:57 pm

Quote:

Originally Posted by colebrooker

... I have recently acquired an old Hakko iron, probably 1980's, model number 3?27...

Might the model number be "927"?

If so, then there's a brief trouble shooting guide on page 7 of the 927 Instruction Manual, which can be downloaded from here:
https://doc.hakko.com/download.php?_...n&kp=927&d=254

Bazz4CQJ · 29th Apr 2017, 1:21 pm

Quote:

Originally Posted by MrBungle

937 is the digital one which is far nicer. Control loop on the 936 analogue unit is dodgy.

When I was thinking about buying the Aoyue, I searched Google for comments. There were some adverse comments about the 936 along the lines that the two buttons for temp up and temp down often seemed to become unreliable after a while, whereas the simple pot control on the 937 appeared reliable (and easy to change if necessary). Did not see any comments on control loops.

B

MrBungle · 29th Apr 2017, 1:45 pm

The problem is there is a ridiculous amount of hysteresis on the 936 model (the analogue control one). If you want the tip at say 200, it will cruise up and down from 170 to 250 which is to be frank, stupid as half the time it won't melt the solder and the rest of the time it'll burn your parts. This is because the element is so far from the tip. Then sometimes it'll get latched up occasionally and blow up the element. That was *after* calibrating it with a thermocouple.

The digital one has a microcontroller in it which seems to have some compensation for this. I think it's probably a PID control loop rather than a comparator with a bit of hysteresis in it. The controls do wear out though; you're right.

This put me off the whole conceptual design of the irons to be honest and when it came to getting something decent, to replace the Antex XS25 that replaced that (and was far better), it was between the Hakko FX-888 and Weller WTCP51. Weller TCP it was. Just turn it on, wait for the first click which takes about 45 seconds and off you go.

Also you have to watch out for some of those clone irons (not Aoyue which are relatively reputable in the scale of things believe it or not) because they are miswired and will kill you the moment you touch the handle. Take anything cheap like that to bits.

Got to be honest, I liked the handle size better than the Weller though. It was tiny which made it easier to get into things

Bazz4CQJ · 6th May 2017, 12:22 pm

After following this thread, I thought I’d dedicate a half hour to checking out how good or bad the temperature control is on my Aoyue 937. I dug out my old Comark thermocouple thermometer (analogue) and set it up to measure tip temperature, and just for comparison, also dug out a FLIR infra red camera.

I switched on the iron from cold and started taking readings after about 10-15 minutes, when everything seemed reasonably stable, and then continued to watch it for another 15 minutes. The Comark showed that the temperature cycling was no worse than +/- 1°C. The FLIR camera has a resolution of 1°C, but did not detect any variation in tip temperature during the same period. It seems to me that the temperature control on this Aoyue is pretty good.

B

MrBungle · 6th May 2017, 1:17 pm

You have to test the iron under load i.e. when it's heating something.

The 937 digital unit is good. The 936 analogue is not.

28th Apr 2017, 12:23 pm	#1
colebrooker Retired Dormant Member Join Date: Feb 2016 Location: Swindon, Wiltshire, UK. Posts: 51	Hakko soldering iron Hello, I have recently acquired an old Hakko iron, probably 1980's, model number 3?27. Initialy it worked but now the display shows eee and no heat. There are 5 pins to the iron from the body. What I am looking for is a circuit diagram. It has a number pad to set temperatures with an R and S pads. I have only been able to use a preset at 350 c. Any ideas on this please? David

28th Apr 2017, 2:29 pm	#2
MrBungle Dekatron Join Date: Jun 2016 Location: London, UK. Posts: 3,687	Re: Hakko soldering iron I've had hakko irons in the distant past. Usually means the thermistor is gone. You need need to dismantle the hand piece and replace the heating element. You can check the element with a multimeter. There should be 4 wires coming out of the element. Two will be near zero ohms and two will be non zero ohms. If that isn't the case then the element is gone.

28th Apr 2017, 3:54 pm	#3
Bazz4CQJ Dekatron Join Date: Apr 2009 Location: Oxfordshire, UK. Posts: 4,935	Re: Hakko soldering iron I think Hakko may also have been sold as the AOYUE brand, so if you search Google for them, you may find relevant info. B __________________ Saturn V had 6 million pounds of fuel. It would take thirty thousand strong men to lift it an inch.

28th Apr 2017, 4:39 pm	#5
MrBungle Dekatron Join Date: Jun 2016 Location: London, UK. Posts: 3,687	Re: Hakko soldering iron Agree. I had an Aoyue 936. Total junk. Don't go near it. Hand piece fell to bits 6 times a day.

28th Apr 2017, 5:45 pm	#6
colebrooker Retired Dormant Member Join Date: Feb 2016 Location: Swindon, Wiltshire, UK. Posts: 51	Re: Hakko soldering iron Thanks, I do only get a reading between 2 wires, so it looks like the hand piece is to be investigated.

28th Apr 2017, 6:33 pm	#7
MrBungle Dekatron Join Date: Jun 2016 Location: London, UK. Posts: 3,687	Re: Hakko soldering iron If this is your only soldering iron be aware you need another one to fix it...

29th Apr 2017, 1:14 am	#9
MrBungle Dekatron Join Date: Jun 2016 Location: London, UK. Posts: 3,687	Re: Hakko soldering iron 937 is the digital one which is far nicer. Control loop on the 936 analogue unit is dodgy. The handle on the iron fell to bits because they shipped the wrong part with it. It took me a year to work that out. Got angry and bought a Weller TCP in the end.

29th Apr 2017, 1:45 pm	#12
MrBungle Dekatron Join Date: Jun 2016 Location: London, UK. Posts: 3,687	Re: Hakko soldering iron The problem is there is a ridiculous amount of hysteresis on the 936 model (the analogue control one). If you want the tip at say 200, it will cruise up and down from 170 to 250 which is to be frank, stupid as half the time it won't melt the solder and the rest of the time it'll burn your parts. This is because the element is so far from the tip. Then sometimes it'll get latched up occasionally and blow up the element. That was after calibrating it with a thermocouple. The digital one has a microcontroller in it which seems to have some compensation for this. I think it's probably a PID control loop rather than a comparator with a bit of hysteresis in it. The controls do wear out though; you're right. This put me off the whole conceptual design of the irons to be honest and when it came to getting something decent, to replace the Antex XS25 that replaced that (and was far better), it was between the Hakko FX-888 and Weller WTCP51. Weller TCP it was. Just turn it on, wait for the first click which takes about 45 seconds and off you go. Also you have to watch out for some of those clone irons (not Aoyue which are relatively reputable in the scale of things believe it or not) because they are miswired and will kill you the moment you touch the handle. Take anything cheap like that to bits. Got to be honest, I liked the handle size better than the Weller though. It was tiny which made it easier to get into things Last edited by MrBungle; 29th Apr 2017 at 1:51 pm.

6th May 2017, 12:22 pm	#13
Bazz4CQJ Dekatron Join Date: Apr 2009 Location: Oxfordshire, UK. Posts: 4,935	Re: Hakko soldering iron After following this thread, I thought I’d dedicate a half hour to checking out how good or bad the temperature control is on my Aoyue 937. I dug out my old Comark thermocouple thermometer (analogue) and set it up to measure tip temperature, and just for comparison, also dug out a FLIR infra red camera. I switched on the iron from cold and started taking readings after about 10-15 minutes, when everything seemed reasonably stable, and then continued to watch it for another 15 minutes. The Comark showed that the temperature cycling was no worse than +/- 1°C. The FLIR camera has a resolution of 1°C, but did not detect any variation in tip temperature during the same period. It seems to me that the temperature control on this Aoyue is pretty good. B __________________ Saturn V had 6 million pounds of fuel. It would take thirty thousand strong men to lift it an inch.

6th May 2017, 1:17 pm	#14
MrBungle Dekatron Join Date: Jun 2016 Location: London, UK. Posts: 3,687	Re: Hakko soldering iron You have to test the iron under load i.e. when it's heating something. The 937 digital unit is good. The 936 analogue is not.