Author Topic: Looking for Yihua 936 clone a1321 mods  (Read 429 times)

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Offline xnotx

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Looking for Yihua 936 clone a1321 mods
« on: January 01, 2018, 10:07:16 am »
Has anyone modded a Yihua 936 to work with the better ceramic a1321 heater?
 

Online xavier60

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Hioki AS100D vom, HP 54645A dso, Fluke 87V dmm, AN8008 dmm, New! Agilent U8002A psu
 

Offline xnotx

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Re: Looking for Yihua 936 clone a1321 mods
« Reply #2 on: January 02, 2018, 12:55:17 am »
I have seen those, ty. Those are a last resort lol

I "feel" like this needs to supply more current with the higher resistance on the new heater, so been reading and watching and learning.
Will then move to target differential voltage for the 2n3906/bt137, so it shuts off. (I think)

I'm not "new" new to electronics, just the inner workings of components, how they are controlled, what they do, etc etc.
So I think this will be a fun learning processes.

I don't have a specific to this model schematic, but do have two "similar" ones I've been going over.


EDIT
That board you linked for the a1321 is nearly identical, lm358 and bt137.
« Last Edit: January 02, 2018, 03:57:47 am by xnotx »
 

Offline phil from seattle

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Re: Looking for Yihua 936 clone a1321 mods
« Reply #3 on: January 02, 2018, 06:27:00 am »
Maybe you just misspoke but you can't "supply more current with the higher resistance".  Ohms law. Higher resistance means lower current. And, you don't supply current, the device draws it based on ohms law.  You can increase current by increasing voltage or reducing resistance. Again, by ohms laws.

V=IR, not just a good idea, it's the law.
« Last Edit: January 02, 2018, 06:29:29 am by phil from seattle »
 

Online xavier60

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Re: Looking for Yihua 936 clone a1321 mods
« Reply #4 on: January 02, 2018, 08:44:14 am »
Has anyone modded a Yihua 936 to work with the better ceramic a1321 heater?
To be certain, are you trying to convert from the type of heater that has the thermocouple sensor.
Hioki AS100D vom, HP 54645A dso, Fluke 87V dmm, AN8008 dmm, New! Agilent U8002A psu
 

Offline xnotx

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Re: Looking for Yihua 936 clone a1321 mods
« Reply #5 on: January 02, 2018, 09:38:29 am »
Maybe you just misspoke but you can't "supply more current with the higher resistance".  Ohms law. Higher resistance means lower current. And, you don't supply current, the device draws it based on ohms law.  You can increase current by increasing voltage or reducing resistance. Again, by ohms laws.

V=IR, not just a good idea, it's the law.
Definitely mis-spoke, rocking a nasty cold lol.
The a1321 heater element is of higher resistance.

To be certain, are you trying to convert from the type of heater that has the thermocouple sensor.
Correct.
Looking at the "a1321 compatible" board on banggood/ebay. These are pretty much identical, so I know it can be fixed to work good with the a1321, I just lack any formal training.
I need a new multimeter though, my old one is unreliable and new one does wonky stuff when I put it on AC.


With this cold, i'm wiped and don't feel like looking up resistor band markings off a picture to reverse engineer the boards from banggood/ebay.
I've watched many op amp videos but things are not sinking in, so time to put it aside until I feel better.

EDIT:
So basically what the issue is, is that the heater circuit is always on, LED is always on, tip gets warm but not hot enough.
I think the tip is getting about 1.x volt, which seems really low.(could be my multimeter)
« Last Edit: January 02, 2018, 09:40:44 am by xnotx »
 

Online xavier60

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Re: Looking for Yihua 936 clone a1321 mods
« Reply #6 on: January 02, 2018, 10:58:47 am »
I wouldn't expect the A1321 heater element to be higher resistance. The PTC thermistor is about 50\$\Omega\$ at normal ambient temperature.
« Last Edit: January 02, 2018, 02:15:43 pm by xavier60 »
Hioki AS100D vom, HP 54645A dso, Fluke 87V dmm, AN8008 dmm, New! Agilent U8002A psu
 


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