Hot air rework station overheating

[AlenZGB]

Here is pictures, i rework it a bit, was no connection duo to fried contacts.
anyhow still not working, now its only blowing cold air,
heater have 82ohms, i think thats ok i guess.

when i plug the AC plug his blowing cold air even if i turn it off, its like it is on
cooling before shuting down.

Any suggestion ?

 

[(*steve*)]

Can you show us what's on the other side?

If you're lucky there's a simple component failure.

Do you know why it failed in the first place?

 

[AlenZGB]

Can you show us what's on the other side?

If you're lucky there's a simple component failure.

Do you know why it failed in the first place?

Nope i dont know,if id know this enigma would be much more easyer to solve.

i post pictures on 2nd page of this thread but ill post it again just to be at the same place.

dont seems anything burning or overheating just looks like i turn it off and its on
shuting down stage when cooling heater action is preforming.

EDIT:
and constantly blowing air on max speed to cool heater element before shut down.
Im sure its some minor problem but cant figure it out

 

[(*steve*)]

Nope i dont know,if id know this enigma would be much more easyer to solve.

i post pictures on 2nd page of this thread but ill post it again just to be at the same place.

Sorry about that. I missed that this was page 3 of a thread. I'm going to try to blame my advancing years, but they're not *that* advanced yet.

I'm also going to assume I asked you if you could read the part numbers on the schematic. I'll go looking back through the thread for that before I ask you

edit: Yeah, I did ask you, but I can't see a response. Can you make out any part numbers on the two 8-legged ICs, the three 3-legged transistors. I'm pretty sure there's markings on mos of them. You may have to get the light just right to photograph them. No need for a photo if you can read them

 

[AlenZGB]

Sorry about that. I missed that this was page 3 of a thread. I'm going to try to blame my advancing years, but they're not *that* advanced yet.

I'm also going to assume I asked you if you could read the part numbers on the schematic. I'll go looking back through the thread for that before I ask you

edit: Yeah, I did ask you, but I can't see a response. Can you make out any part numbers on the two 8-legged ICs, the three 3-legged transistors. I'm pretty sure there's markings on mos of them. You may have to get the light just right to photograph them. No need for a photo if you can read them

Sorry
now im gonna blame my advanced years

Part number of the board is only JH-02 i googled but didnt find anything.

8 lagged ICs are HA17555 above that is 4VL but im not sure i think HA17555 is enough.
both ICs are the same number H17555

3 laged transistor is BT136-600D
I change tham both.

 

[AlenZGB]

I found one more transistor on board, visually dont seem to be bad.
it is MCR100-6.
how can i test it?

 

[(*steve*)]

Hahaha, would you believe that those ICs are 555s!

(Now where is that person who said you'd never find one in a commercial product?)

Here are the specs.

The BT136-600 is a 600V 4A triac (As I'm sure you're aware). There's 2 of these?

The MCR100-6 is a 400V 0.8A sensitive gate SCR.

It also looks like you've cleaned up the board around the inductor. Do you think the dark stiff was there originally? Did you check the inductor for missing or damaged enamel insulation?

It's great the parts are so simple and easily available. You could just go ahead and replace the two 555s and the SCR on spec. It may take longer to test them.

But I'd probably take a reading of the voltage on the power pins for the 555s first. Does this device have a transformer or is this board live?

 

[AlenZGB]

I doubt the dark stiff was originally but i cant tell for sure.
Im just going to buy 2 555s to replace tham, it has 2 of tham
And MCR100-6 also i wanna replace.

As far as transformer goes it has matsushita ha1-dc24v, guessing this is
some kind of transformer.

looks like this
Internet image

EDIT:
is it possible that when other few resistors blown, that damage MCR100-6 and 555s ?
so they now wont work as they should ?

Did you check the inductor for missing or damaged enamel insulation?

You mean that toroid or something else ?
i chack it clean as much i the copper wire insulation may get off, that could be that black thing.
what resistance should i get when measuring ?

 

[AlenZGB]

In my store they didint have HA17555 instead he give me NE555 said thats the same thing,
also give me MCR22-8 instead of MCR100-6

What you think of that ?

 

[(*steve*)]

Im just going to buy 2 555s to replace tham

I'm not certain it will help, but they're cheap enough to just replace.

As far as transformer goes it has matsushita ha1-dc24v, guessing this is
some kind of transformer.

It's a relay. It's unlikely to be damaged.

is it possible that when other few resistors blown, that damage MCR100-6 and 555s ?
so they now wont work as they should ?

That's possible. something precipitated the fault. It may not have been any of these (in fact that's unlikely) but if any were taken out the device would fail thereafter.

You mean that toroid or something else ?
i chack it clean as much i the copper wire insulation may get off, that could be that black thing.
what resistance should i get when measuring ?

it should have a very low resistance. My concern is that the insulation has come off and that adjacent turns are electrically connected. This can't easily be measured. You would need to measure the Q of the inductor.

In my store they didint have HA17555 instead he give me NE555 said thats the same thing,

Yep, that's fine.

also give me MCR22-8 instead of MCR100-6

Yep, that's a more rugged part, but otherwise quite similar.

 

[AlenZGB]

Steve, i really appreciate help and will to help me with my hot air station but i wont be needing help anymore i fix that on a wrong way
Damn china stuff have similar connectors and i mix 2 of tham and kaboom.
Oh well we need to learn from mistakes. Problem solved hahahahaha
Not quite what i was planed

But anyways i was wondering. You said i should check voltage on power pins.
I try to do it but then something wierd happen, picture will be above this. With circles in
color, this color on 555 mean how much can i read and with what probe (red or black)

When i connect black probe on orange color wire on pin 2 i get 89V with red probe on 555.
but when i try to do it on other 555 timer i dont read anything, and when i connect red probe on black wire on pin 3 i get 89V on other 555 timer but with black probe.

Am I doing it wrong or it should be that ?

What of this is positive and what is negative ?
since it dont have any transformator to transform it from AC to DC.

 

[(*steve*)]

Steve, i really appreciate help and will to help me with my hot air station but i wont be needing help anymore i fix that on a wrong way
Damn china stuff have similar connectors and i mix 2 of tham and kaboom.

*ouch*

But anyways i was wondering. You said i should check voltage on power pins.
I try to do it but then something wierd happen, picture will be above this. With circles in
color, this color on 555 mean how much can i read and with what probe (red or black)

The correct way would be to place the black probe on the ground pin (1) of the 555 and the red probe on the Vcc pin (8).

When i connect black probe on orange color wire on pin 2 i get 89V with red probe on 555.
but when i try to do it on other 555 timer i dont read anything, and when i connect red probe on black wire on pin 3 i get 89V on other 555 timer but with black probe.

Am I doing it wrong or it should be that ?

It all depends on what you're measuring it with respect to.

What of this is positive and what is negative ?
since it dont have any transformator to transform it from AC to DC.

OK, I didn't realise there was no transformer. It's pretty dangerous working on live equipment. :-o

 

[(*steve*)]

If you're really interested, it's probably still possible to repair, but it may not be economically viable.

It's the sort of thing you do as a challenge.

 

[AlenZGB]

The correct way would be to place the black probe on the ground pin (1) of the 555 and the red probe on the Vcc pin (8).

Oh dumb me didnt think of that

OK, I didn't realise there was no transformer. It's pretty dangerous working on live equipment. :-o

I know, i use plastic gloves like a doctor

How is possible to know where is positive and where is negative poles, on AC dont they change 50 times per second or so? (50Hz, one change per second)
correct me if im wrong.

If you're really interested, it's probably still possible to repair, but it may not be economically viable.

It's the sort of thing you do as a challenge.

I think ill skip on this one.
I crap my pants when i turn it on and it make a kaboom sound.


but i need to learn from it
Today i learn how to measure it the right way and to destroy it the wrong way :rolleyes

 

[(*steve*)]

How is possible to know where is positive and where is negative poles, on AC dont they change 50 times per second or so? (50Hz, one change per second)

Yeah, 50Hz means that it goes through a single cycle of zero up to the positive maximum, then back through zero down to the negative maximum, and back up to zero again 50 times every second.

There is no positive or negative. But somewhere on that board that voltage will be reduced and rectified and smoothed to a DC voltage.

Because this device doesn't have a transformer, the DC is probably relative to the neutral pole of the mains. That still makes it dangerous.

I think ill skip on this one.
I crap my pants when i turn it on and it make a kaboom sound.

I don't blame you. You have just experienced a little of what it means to say that the mains is a high energy source.

It does demand respect.

but i need to learn from it
Today i learn how to measure it the right way and to destroy it the wrong way

Even if it's not going to be repaired, you may be interested in finding out how it generates an AC rail. You should be able to trace through the circuit and find out that it (a) does something unusual with a capacitor) and (b) has the rail essentially connected to the mains.

I wouldn't recommend plastic gloves as a means of protecting yourself.

The best way is:

a) don't connect or disconnect anything while the power is applied.

b) remove the power plug, don't just switch the power off

c) even in this case, assume the power is on and try to use just one hand.

d) wear rubber or plastic soled shoes.

e) have someone else nearby just in case...

f) try to keep one hand in your pocket when power is applied.

 

[AlenZGB]

Yeah, 50Hz means that it goes through a single cycle of zero up to the positive maximum, then back through zero down to the negative maximum, and back up to zero again 50 times every second.

There is no positive or negative. But somewhere on that board that voltage will be reduced and rectified and smoothed to a DC voltage.

Because this device doesn't have a transformer, the DC is probably relative to the neutral pole of the mains. That still makes it dangerous.



I don't blame you. You have just experienced a little of what it means to say that the mains is a high energy source.

It does demand respect.



Even if it's not going to be repaired, you may be interested in finding out how it generates an AC rail. You should be able to trace through the circuit and find out that it (a) does something unusual with a capacitor) and (b) has the rail essentially connected to the mains.

I wouldn't recommend plastic gloves as a means of protecting yourself.

The best way is:

a) don't connect or disconnect anything while the power is applied.

b) remove the power plug, don't just switch the power off

c) even in this case, assume the power is on and try to use just one hand.

d) wear rubber or plastic soled shoes.

e) have someone else nearby just in case...

f) try to keep one hand in your pocket when power is applied.

Thanks for the support, for now ill close it to take a rest for a while, when i`ll have
more time ill play with it. Maybe try to fix it one day to

Al far as gloves goes,i saw that from the man who was fixing car lift i our
workshop, he was using that surgeon gloves,seems like good choice
guess i was wrong ?

 

[(*steve*)]

Thin gloves are fine for keeping oil of your hands. If they tear or get a pinprick you get dirty hands.

Electrocution doesn't dirty your hands, it kills you. Also the thickness of the gloves is such that the voltage *might* jump across the gap -- the gloves are not designed to protect against that.

Whilst they might offer some protection, would you bet your life on them?

 

[AlenZGB]

Thin gloves are fine for keeping oil of your hands. If they tear or get a pinprick you get dirty hands.

Electrocution doesn't dirty your hands, it kills you. Also the thickness of the gloves is such that the voltage *might* jump across the gap -- the gloves are not designed to protect against that.

Whilst they might offer some protection, would you bet your life on them?

You are right,didnt think of that so far
Cant know everything

 

[AlenZGB]

I clean all the black stuff that happen from kaboom, and it seems that one diode
blown, for now, maybe 555 timer also black was on his pins too.

Going to buy that one diode and try to fix it once again, hope this time wont be black
spots


And i found how i can change AC to DC, with diode bridge. need to try that sometimes

When i change it ill post pictures.

 

[AlenZGB]

Going back to hot air station repair project. Star date 32100421.4, after changing 3 fried diodes, and 2 suspicious capacitors and air volume potenciometer. same thing happen, when switch is in off position just blowing to cool down
heating element, when i turn it on only blows cold air.

Then ill check other potenciometer that is on the heater side, it has 3 pins and when i test middle and left pin nothing happens, but when i test middle and right pin i get beep, like bad diode or short circuit.
Could that be the problem ?