Something Heat dun death Ray

[David Banner]

Long Story short... my Makita 6500 heat gun that's had bugger all use was loaned to a mate who used it to melt a candle. Don't even ask. I've been told he held the nozzle of the heat gun into an upside down glass container to melt the candle, and then after letting the wax partly cool he started the process again. I've been told at some point there quick escape of wax from the glass and the heat gun cut out. The motor runs on both speed settings, but the element and gun display are notworking. I've included images of the gun so you can see the model, and a video of me switching the gun on and off. I understand it could be anything but the element ir maybe some other part. I can take it apart and I have a multimeter, but I wouldn't have a clue where to start with testing this for repair. I can't afford to buy another unit, so if I can't repair this one I've lost the use of that tool, and no my ex mate isn't coming to the table to replace the heat gun. At least not yet. I will be very grateful for any help wisdom or magic anybody can offer that'd see the heat gun fixed. I can dissasemble it and take photos if required. Thanks

 

[Les Jones]

If you are lucky it may have a thermal fuse that has failed. If it is not that then it is probably the heating element. You will have to take it appart to find out.
Les.

 

[Nigel Goodwin]

If you are lucky it may have a thermal fuse that has failed. If it is not that then it is probably the heating element. You will have to take it appart to find out.
Les.

Yes, presumably he's blocked the air flow causing it to over heat, and probably blown a thermal fuse - most items of this type have them for safety reasons. So as Les Jones said, lucky it's a thermal fuse, unlucky it's the element.

 

[David Banner]

OK. Here's an update of the disassembled unit. I've exposed the the thermal fuse in one of the images. Somebody said to continuity check it? - So I will do that, but more generally I've inspected the element and it kind of looks OK. Like I said before the fan motor is working on both settings, so the swicth is working - at least to power the fan motor, would there be something powering the rest of the unit from the on switch? - All advice is welcome. The advice thhat helps me fox this is really welcome. Thanks folks for you patince and help with this. The images are in no particular order, and I can take more images if you need a close up or something from a different angle.

 

[Nigel Goodwin]

The thermal fuse is the little silver thing in picture 20241219_205912.jpg, you need to test it on low ohms using a multimeter, if OK it should read zero ohms, or very close. Most likely it's O/C and will read high or infinity.

 

[David Banner]

I tested across the fuse and it is not blown, using the continutity setting on a multimeter. I've done a visual inspection on the element and I can't see any damage, no breaks that I can see. I checked the continuity between the top of the element hook, that on my unit clips onto a ceramic clip at the nozzle end of the gun, and the red wire on the PCB, which is where I traced it back to, and it's continuous. The top side of that connection on the PCB looks gammy, but I think that's just how it might be, like a sealant of sorts. When I check continiuty for the red conenction I also check it off the black one, and I am getting continuity on this connection also, should that be the case? - If there is a PCB test that I can do I'd be grateful for a heads up. With the Display not working, how can I check the board for a short? - with limited tools?

 

[David Banner]

The thermal fuse is the little silver thing in picture 20241219_205912.jpg, you need to test it on low ohms using a multimeter, if OK it should read zero ohms, or very close. Most likely it's O/C and will read high or infinity.

Thanks Nigel. 0.4 ohms on the multimeter.

 

[Nigel Goodwin]

Thanks Nigel. 0.4 ohms on the multimeter.

That's OK then.

 

[Les Jones]

How many settings are there on the slide switch and what are the markings on each position ?
Does the LCD display show anything and do the up and down tempartaure setting buttons change the display? ( I could not fined a manual on line but some reviews seem to indicate that this is how the temperature is controlled.)
I think picture 205201.jpg is the temperature controller board.
Did any of the wax get inside the heat gun. (I was thinking that maybe it got between the contacts on the switch.
How many wires connect to the element assembly ?
Les.

 

[David Banner]

How many settings are there on the slide switch and what are the markings on each position ?
Does the LCD display show anything and do the up and down tempartaure setting buttons change the display? ( I could not fined a manual on line but some reviews seem to indicate that this is how the temperature is controlled.)
I think picture 205201.jpg is the temperature controller board.
Did any of the wax get inside the heat gun. (I was thinking that maybe it got between the contacts on the switch.
How many wires connect to the element assembly ?
Les.

The Slide switch has a 1 and 2 and 0 setting, and both work to power the fan.
No display, and the buttons don't change the temp, it blows cold on both speed settings.
202412 is the temp controller board
Yes wax got inside the gun but specs, it's be hard to impossible to find it.
4 wires to teh element assembly.
If you need better pics of any of this just ask.

 

[David Banner]

Here is a closer images of the temp controller board, and the other board between the swicth and temp board and also connects to the element, and lastly that black circle that's wrapped in something, dunno what it is, bu I doubt it's failed because it's wrapped, which is why it's probably the broken part. All help appreciated.

 

[Lightium]

Tell your "friend" next time to use his own microwave oven to melt wax.

 

[David Banner]

Tell your "friend" next time to use his own microwave oven to melt wax.

One Solution.

 

[Les Jones]

Can you post a picture of the etch side of the board that the slide switch is mounted on. Also can you post a second copy showing the colours of all the wires going to this board and if possible where the other ends of these wires connect to. If you know how to can you trace out the schematic of the temperature control board and tell us the part number of the TO220 device mounted on the heat sink. (I suspect it will be an SCR or triac.)
Les.

 

[David Banner]

Can you post a picture of the etch side of the board that the slide switch is mounted on. Also can you post a second copy showing the colours of all the wires going to this board and if possible where the other ends of these wires connect to. If you know how to can you trace out the schematic of the temperature control board and tell us the part number of the TO220 device mounted on the heat sink. (I suspect it will be an SCR or triac.)
Les.

Les, You're a gent, and I owe you a better effort than to do what I am about to do, which is pull the plug. I feel the help here's been geneuine and my repair skills are limited. I reassembled the gun and fired it up and it was blowing, hot but I beleive the display is blown, not is may be repairable, but that repair was always going to be beyond me. I was hoping a fuse or something similar would have revealed itself and I coud have repaired or replaced it. I will be getting the unit fixed, though god knows where because people seem to want to stay clear of these types of heat guns. I don' throw stuff out if I feel tehre even a slim chance of repair.

Thanks again to you and everybody else who made a positive contribution.

 

[Les Jones]

I'm pleased that you have got it partly working. Until I started to look for information on your hot air gun I thought it was just simple one. (I have never seen one with proper temperature control.) With no display on the LCD I thought that there was no DC supply to the electronics on the temperature control board. This would have meant that there would be no trigger pulses to the SCR/Triac which controls the power to the elements. While I was looking for information on your heat gun I found a site that had many spare parts for your heat gun but I did not make a not of the URL for the site. If you google "Makita 6500 heat gun spares" you may find it. Even though the display does not work does the temperature control work ?

Les.

 

[David Banner]

I'm pleased that you have got it partly working. Until I started to look for information on your hot air gun I thought it was just simple one. (I have never seen one with proper temperature control.) With no display on the LCD I thought that there was no DC supply to the electronics on the temperature control board. This would have meant that there would be no trigger pulses to the SCR/Triac which controls the power to the elements. While I was looking for information on your heat gun I found a site that had many spare parts for your heat gun but I did not make a not of the URL for the site. If you google "Makita 6500 heat gun spares" you may find it. Even though the display does not work does the temperature control work ?

Les.

I don't think the temperature control worked. I understand the difference in what your asking, and I did push the up and down temp buttons while it was running, but i was a bit distracted because I was in 'putting it away' mode. I'll read up about what you've said about the scr/triac and if I identify it easily, hopefully I can test it. I did look for chematics for the boards, and there are board numbers, so I intended to search for them today to see if htere's any info out there on them. I will come back to this thread, whether I manage to fix it with advice, or whatever the outcome. Thanks again Les.

 

[Lightium]

Are there any MOSFET's on the board to test?