Harbor Freight Tools Heat Gun Item 96289 JSRF-601C Repair

[captainKKK]

Re: Harbor Freight Tools Heat Gun Item 96289 JSRF-601C Repair

UPDATE: Originally, I ordered 1N5408 from aliexpress and since that was taking too long, I paid twice the price for half the quantity from a USA seller on eBay, for delivery in a week. In the pics herein, you can see the eBay sellers product is on the RIGHT and the Chinese seller on Aliexpress is on the left. If SIZE MATTERS, then the Chinese Aliexpress product is superior. Also note, not only is the chinese diode itself large in diameter and length, the diameter of the cathode and anode wires on the chinese product is larger. Remember, herein the USA sold eBay product blew out 3 times before I placed the heatsink. Just FYI. Opinions?

[petehall347]

Re: Harbor Freight Tools Heat Gun Item 96289 JSRF-601C Repair

lots of good stuff is produced in china under licence . and lots are produced on the cheap that anyone can sell on .
one on the left looks better markings to me .

[eccerr0r]

Re: Harbor Freight Tools Heat Gun Item 96289 JSRF-601C Repair

The 1N5408 must be bigger than the typical 1N4007s I hope people have seen before... Need a scale to really tell how big they are, but yes they should be larger to dissipate more heat and hence support more amperes.

Some diodes, from left to right:

(15 amp stud rectifier)
1N1614 (1969)

(6 amps plastic)
P600M

(3 amps)
MR851 Motorola (1983)
SMR750

(1 amp)
1N4007 Motorola (1981)
1N4007 (??)

1N1379 240A

[stj]

Re: Harbor Freight Tools Heat Gun Item 96289 JSRF-601C Repair

UPDATE: Originally, I ordered 1N5408 from aliexpress and since that was taking too long, I paid twice the price for half the quantity from a USA seller on eBay, for delivery in a week. In the pics herein, you can see the eBay sellers product is on the RIGHT and the Chinese seller on Aliexpress is on the left. If SIZE MATTERS, then the Chinese Aliexpress product is superior. Also note, not only is the chinese diode itself large in diameter and length, the diameter of the cathode and anode wires on the chinese product is larger. Remember, herein the USA sold eBay product blew out 3 times before I placed the heatsink. Just FYI. Opinions?

the one on the left is new and has lead-free solder coated wires, the one on the right looks very old.

[eccerr0r]

Re: Harbor Freight Tools Heat Gun Item 96289 JSRF-601C Repair

I could have sworn I had a 1N5408 somewhere, and I finally found it... same size as the MR851/SMR750. And yeah I've noticed a lot of my old diodes have "shitty paint jobs" that scratch off very easily. However the size difference of the two you have is probably inconsequential, though if they are both the size of a "tiny" 1N4007, that's a problem...

And it could very well that the "USA seller" bought a boatload (literally) of counterfeit 1N5408's to resell...

[stj]

Re: Harbor Freight Tools Heat Gun Item 96289 JSRF-601C Repair

those p600's bring back memories!

i used to fix boards that had an early type on them, the package had pads with soldered on leads.
when the voltage regulator shorted they used to get so hot they desolderd themselves and fell into the casing, leaving the wires on the board!!!

[eccerr0r]

Re: Harbor Freight Tools Heat Gun Item 96289 JSRF-601C Repair

Yeah I've heard a bunch of horror stories about the P600's as well. Though rated for 6A, that thing must get HOT, how could plastic deal with that much heat!!! IIRC the P600's seem to be readily available and probably the highest current plastic tubular diodes available and people readily use it reverse voltage protection, including things that require many more than 6A.

I'd imagine at that much current, one needs to look into heat sinking, and should be using TO-220 diodes instead... or some other solution...

[stj]

Re: Harbor Freight Tools Heat Gun Item 96289 JSRF-601C Repair

it used to be common to loop the leads before going on the pcb so the heat would disipate before it reached the board!

[eccerr0r]

Re: Harbor Freight Tools Heat Gun Item 96289 JSRF-601C Repair

And now they keep leads short to use foil as heat sinking

[jim x 3]

Re: Harbor Freight Tools Heat Gun Item 96289 JSRF-601C Repair

There must be several (multiple) versions of item 96289. My manual indicates revision 11a. There are no diodes present in my heat gun. The wiring diagram for my heat gun is attached.
--Jim x 3

[jim x 3]

Re: Harbor Freight Tools Heat Gun Item 96289 JSRF-601C Repair

There must be several (multiple) versions of item 96289. My manual indicates revision 11a. There are no diodes present in my heat gun. The wiring diagram for my heat gun is attached. Resistance values may not be accurate given the condition of my heating coils.
--Jim x 3

[sam_sam_sam]

Re: Harbor Freight Tools Heat Gun Item 96289 JSRF-601C Repair

There must be several (multiple) versions of item 96289. My manual indicates revision 11a. There are no diodes present in my heat gun. The wiring diagram for my heat gun is attached. Resistance values may not be accurate given the condition of my heating coils.
--Jim x 3

Then it might be using a ac type motor

[jim x 3]

Re: Harbor Freight Tools Heat Gun Item 96289 JSRF-601C Repair

@sam x 3

Well I mis-spoke. There is no diode in my heat gun at the switch that provides 2 power settings.

However (as you can see from my diagram) there is a 4 diode bridge providing DC to the motor.

Jim Jim Jim

[JakeBlanton]

Re: Harbor Freight Tools Heat Gun Item 96289 JSRF-601C Repair

UPDATE: Originally, I ordered 1N5408 from aliexpress and since that was taking too long, I paid twice the price for half the quantity from a USA seller on eBay, for delivery in a week. In the pics herein, you can see the eBay sellers product is on the RIGHT and the Chinese seller on Aliexpress is on the left. If SIZE MATTERS, then the Chinese Aliexpress product is superior. Also note, not only is the chinese diode itself large in diameter and length, the diameter of the cathode and anode wires on the chinese product is larger. Remember, herein the USA sold eBay product blew out 3 times before I placed the heatsink. Just FYI. Opinions?

Just because it is a US seller, it doesn't mean that the product is made in the US, especially if you are buying it off of eBay... Not that there is anything necessarily wrong with stuff made overseas -- it's a matter of quality control and whether the company that is subcontracting the Chinese manufacturers is diligent on quality control and ensuring that the Chinese manufacturers meet the requirements of the product... If they just tell the Chinese that they want a certain product for a certain price, then the Chinese will do whatever is necessary to increase their profit margin, even if it affects durability... You need to keep on top of your subcontractors to ensure they meet your requirements...

There are also sellers on eBay that are listed as "US sellers", but they are nothing more than a front for a foreign seller. If you buy something from them, there's still a good chance that it will be shipped from China. Part of the reason for this is that due to certain international postal agreements, it is cheaper for them to ship from China to the US than to ship internal in the US.

[JakeBlanton]

Re: Harbor Freight Tools Heat Gun Item 96289 JSRF-601C Repair

I have a problem with this heat gun also. Not too long after I bought it, plastic shroud that covers the metal shroud over the heating element fell off, but since it still worked, I just kept using it. Not too long after that, the low temperature side quit working, but since I mainly needed the high temperature side, I didn't think it was worth returning to the store. The other day, the high temperature side quit working, but it's well past the warranty period (besides, I don't have the original receipt after this length of time), so there's no returning it.

So, I decided to open it up and see if I could determine what went wrong or maybe salvage some parts for use in other future projects. Upon opening it up and tracing the wiring, I noticed what looked like some strange electrodes that went across the outer connectors on the switch. I initially thought it must be some sort of heat protection mechanism that expands when it gets too hot, thus the gap between the electrode pads. Examining it further and a bit of research on the web allowed me to determine that it was instead a diode. As it turned out, the diode had split longitudinally, giving a nice cross-sectional view of how it was constructed.

From my examination of the circuit, it appeared that the diode was only being used when the switch was in the low power setting, so it's possible that when it blew, it was the cause of my losing the low power feature initially, but it doesn't explain the loss of the high power feature at present. Symptoms are that neither the fan spins nor the element heats up. When plugged into the wall, 120V is on the outer terminals of the switch as appropriate for whatever position I have the switch in, thus the switch is good. I've also removed it completely from the circuit and tested the resistance on it and everything is normal. I have tested the motor by putting 4VDC and 8VDC on the input to the rectifier board that is on the back of the motor. As can be expected, the motor turns faster with 8VDC than with 4VDC, but it is noticeably slower than the normal speed of the motor since from what I've gathered, it is rated for 12-24VDC.

I suspect that the next thing to check will be to disassemble the heating element assembly.

[sam_sam_sam]

Re: Harbor Freight Tools Heat Gun Item 96289 JSRF-601C Repair

One thing to check is the wires to the heating element crimps because these have been issues from what I seen

Because I have one of heat guns and that what happened to mine so I bought another new one because they are not worth repairing them just slavish the good parts

[JakeBlanton]

Re: Harbor Freight Tools Heat Gun Item 96289 JSRF-601C Repair

One thing to check is the wires to the heating element crimps because these have been issues from what I seen

Because I have one of heat guns and that what happened to mine so I bought another new one because they are not worth repairing them just slavish the good parts

Looking through my spare parts box, I notice that I have a 1N5402 diode (probably salvaged from a hair dryer that broke after being dropped or something). I don't remember how it was installed in the hair dryer, but I would not be surprised if it was used for the same thing as the 1N5408 diode is used in the HF heat gun. The motor in the hair dryer seems slightly larger / heavier and it also has a rectifier board mounted to the back of it, albeit one that uses discrete components instead of surface mount ones. That's probably an indication of how old it is and how long it lasted -- lasted my wife since I keep what little hair I have remaining so short that there is nothing to dry...

Looks like the 1N5402 might be a bit undersized as a replacement for a 1N5408 (assuming that they are using the full specifications of the 1N5408)...

https://cdn.badcaps-static.com/pdfs/...85f39a3daa.pdf

[eccerr0r]

Re: Harbor Freight Tools Heat Gun Item 96289 JSRF-601C Repair

Scratch that. No, don't use the 1N5402 for the single diode, thought it was being used for the bridge where 1N5402s would work fine. The other lone diode needs to be 1N5408 (1N5406 or 1N5407 would do in a pinch, or use a P600J/P600K/P600M).

[clearchris]

Re: Harbor Freight Tools Heat Gun Item 96289 JSRF-601C Repair

Any of these new ones have GFCI cords? If hair dryers have them... these should be even cheaper to make....

I think I have the same one. Bought it years ago for possibly $6, definitiley not more than $10. Not sure there's room in the BOM for a GFCI cord.

[momaka]

Re: Harbor Freight Tools Heat Gun Item 96289 JSRF-601C Repair

^ Agreed.
Also, I don't see what would be the point of a GFCI plug in a heatgun. For a hair dryer, it matters, because its anticipated most people would use them in the bathroom, where it's humid and the user may be grounded and thus at much higher risk of electrocution. Same goes for most electric power washers I've seen... obviously because water + electricity may not be a good mix for the end user. But heat guns... meh, not really needed.