Best BST-863 hot air station

[dreamcat4]

I might be looking at this wrong but if the resistors on your ESC are the same as mine that little transistor "T7" will never turn on because R20 which is in series is 100k (+ the resistance of R7, R8 or R9) and R19 which is a pull down immediatley after is 10k

Ah yes, sorry for not being clear enough earlier. I seem to have all of the same silkscreen markings (component names) over here. For which resistors, capacitor etc.

But the value of R20 i measure is not same as yours (not 100k):

R19 = 8.9k
R20 = 25.1k
R7 = 8.9k

I do not believe the other 2 hall sensors, R8 and R9 matters for A1. Because they do not connect to R20. Instead they connect to +5v (pulled up HIGH), which is for the bldc controller IC only.

But those are similar:

R8 = 9.7k
R9 = 9.7k

So maybe that can help you to get yours working.

I think they messed this up in the design.

Yes, or it could maybe be a component error in manufacture. My board is dated: BST-2019.4.23. Perhaps the issue was specific to earlier models only. Or to a bad batch.

Did you try do disconnect A1 only and check if the blower works that way?

Thanks for explaining this part. What i did was to moved the A1 pin to GND, on next header. Because it seems active LOW (pull up otherwise).

* The blower does not work, however I did see some PWM signal squished. This means it's almost 0v. But you can still see a very small increase (few mV) bumps, when the PWM is high.

* So I think that is my next area to focus on.

What I have also done is to rule out the blower bldc FAN itself. This is not anything about the handle. This is only the FAN:

* Removed the fan housing and inspected the fan blades
* They are all fine. So the fan did not explode
* Checked all 3 motor coils - all coils are about 12 ohm. They connect circular in a loop to each other
* Checked all 3 hall sensors [HA HB HC], (for shaft position) all the position sensors are working

The hall sensors inside the motor become active during rotation. And the closed magnet reads about 12 ohm (same value as the coil resistance). And off is high impedence.

* Problem is somewhere else on esc board
* I cleaned the board with IPA, to remove tin whiskers
* Found they did put some white paint between the MOSFET legs
* It looks just like the other silkscreen, white lines. However it not!
* It is an extra layer of paint after above the silkscreen

They did on the top side the mosfets. But not on the bottom side, where the motor connector is. They missed that

My next focus is to look for why the PWM signal is killed, and drained to almost nothing. That is not normal operation, is it?

So maybe there is a bad (shorted) capacitor? Or other active component like small transistor? Maybe that is worth to investigate

[tatel]

Thanks for the feedback. This is the github repository for the code but I still have to organize some things before I post it, soon. https://github.com/RandomHacks-Git/Best-Improvement

Well, code can't be called free until effectively released...

As for the knobs I did order them ages ago but they never arrived and that is why they aren't included. I will order some more on july 1st as hopefully aliexress/ebay will start to collect vat at checkout because I don't feel like paying a service fee to the post now with the new customs rules.

These new VAT rules are going to be a circus, I'm afraid. I'll be abstaining from buying anything from outside EU until the way these rules work -and sellers react- is clear.

[thm_w]

Anyway, here is photos of the tin whiskers. This was after breaking them off (not realizing before). So there was more than 1 whiskers per solder joint. And clearly the whiskers a plenty long enough to bridge and reach the next contact. Before I messed them up sorry!

So they aren't fibers from something, they are conductive?
wild

[wraper]

Anyway, here is photos of the tin whiskers. This was after breaking them off (not realizing before). So there was more than 1 whiskers per solder joint. And clearly the whiskers a plenty long enough to bridge and reach the next contact. Before I messed them up sorry!

So they aren't fibers from something, they are conductive?
wild

Zero chance those are tin whiskers. Just some fibers stuck to PCB. Tin whiskers grow from solder joint, they cannot just lie on a solder joint, with middle touching it and both ends being free.

[dreamcat4]

they are only sitting in those moved about position because i already broke them off and tried cleaning them off partially. before first realizing what they actually were. and before taking any of the photos.

fibres have some curved shape. these are not that because 0% are curved. they also are made from metal when handling them they have a grey metallic sheen and they break / crack into pieces very easily. fibres do not behave in that way. also there still stubs of where the lines starts eminating from the roots actually embed from the body of the round solder joints itself. before getting to the length when they become delivate and broken off. and those begingins of the roots which were not fully cracked off are still in fact present on the solder joings.

it is in fact tin whiskers. i am 100% sure

[wraper]

They are also too thick for being tin whiskers. And I ho no idea why you think that fibers must be curved.

[dreamcat4]

They are also too thick for being tin whiskers. And I ho no idea why you think that fibers must be curved.

they are really actually very thin. sorry you don't seem to be saying anything of a value that also matches the reality

and you misquote me: i never said fibres must be curved. i said 0% of them are curved. which is a different meaning. it means: there is no positive proof of being a fibre. because something that bends or curl would prove your point. but it doesn't,

all i see here is somebody who wants not to walk back their statements. and admit they are wrong. and you never have this in front of you IRL. you are backseat driving from the beginning

what do you think, why i would not be saying this to begin with if there was not strong enough scrutiny already to close examination? i have seen before that is fibres so many times. this is not the same thing. it's also not anything else that grows in this ways from a solder joint, like a crystal. and at straight angles

my description and photos matches it here well enough. so what evidence do you have to the contrary?

nothing 

just an opinion you are unwilling to change, for looking like a bigger fool for being so wrong about it. and then not conceding the mistake

because your reputation means more to you than the truth

[thm_w]

they are really actually very thin. sorry you don't seem to be saying anything of a value that also matches the reality

Don't overthink it, just measure the conductivity of one if you have a chance and still have it around, if not forget it and don't worry about any comments. 

[tatel]

Well, I got this station delivered today, and all I can say is it doesn't work

I get the handle out of the holder and screen changes, so the reed switch seems to be working. But, fan never goes on, and heater seems to be on hollidays.

I have to say that Banggood has delivered to me wrong or faulty items in three of my last four orders. They solved all the issues quite quickly, but it looks as if their QC is with my station's fan and heater: on hollidays.

[dreamcat4]

yeah my unit was also doing a similar misbehaviour from time to time occasionally. with the display showing 000 temperature. maybe just some buggy behaviour? which it should snap out of. do not really know what else to make of it. perhaps others here know better

btw which i dont worry about anymore. since ordering the excellent new upgrade kit, will replace the mcu and firmware

but the big question is: does your fan spin during power up? because it should do that for 2 sec regardless of any other issues. to know the fan works

[tatel]

but the big question is: does your fan spin during power up? because it should do that for 2 sec regardless of any other issues. to know the fan works

No, it doesn't

[dreamcat4]

huh. maybe they updated the firmware recently then? to stop the fan spinning on startup?

otherwise if it really is DOA then that is pretty bad form

if it is indeed brand new from factory (and not any type of refurb etc), then DOA not happen with even the most basic QA. except for due to damage in shipping

and i dont really see why shipping would cause any real or serious damage. however if they have not used enough silastic on all the connectors. to stop them from being vibrated loose

so i suppose maybe you can reasonably open the case to check that all the cables are properly seated and still all connected up.

but you should also not do anything to jeopordize your position for RMA / complain, returning it, get a refund or compensation

so maybe opening the case is a bit counter to that objective. however its also the only way to check for loose connector plugs so.... idk what else. given how much hassle it is to return these things all the way back to china. unless it was sent from a reseller more local to you. like within europe etc.

[tatel]

huh. maybe they updated the firmware recently then? to stop the fan spinning on startup?

otherwise if it really is DOA then that is pretty bad form

if it is indeed brand new from factory (and not any type of refurb etc), then DOA not happen with even the most basic QA. except for due to damage in shipping

and i dont really see why shipping would cause any real or serious damage. however if they have not used enough silastic on all the connectors. to stop them from being vibrated loose

so i suppose maybe you can reasonably open the case to check that all the cables are properly seated and still all connected up.

but you should also not do anything to jeopordize your position for RMA / complain, returning it, get a refund or compensation

so maybe opening the case is a bit counter to that objective. however its also the only way to check for loose connector plugs so.... idk what else. given how much hassle it is to return these things all the way back to china. unless it was sent from a reseller more local to you. like within europe etc.

Fortunatelly they ship this thing from Spain. Otherwise, with the new EU VAT rules coming into force, I wouldn't have purchased it. So, no need to return it to China, and a couple of days are enough to get this thing delivered over some 300 miles distance. Not 3000.

I'm not going to open it indeed, althougth I would be inclined to do so. I agree this is probably an easy fix, but I'm letting those Banggood guys do their work.

Parcel was in good shape. I'm missing perhaps the protective film on the screen. But, IIRC, it could be inside the case? Anyway I'm willing to return it, and let Banggood manage this matter. They have always given satisfactory and quite fast solutions to me.

After getting a working station I'm going to change the board anyway, but first I'm going to make sure I have a good working one out of the box.

[SteveyG]

Well, I got this station delivered today, and all I can say is it doesn't work

Your last picture seems to tell the story (the moon symbol). You must make sure the handpiece is seated and activating the reed switch when the unit is first turned on otherwise it'll never allow you to use it (just in case it's sitting out of the cradle).

Can you check this? This stumped me once or twice until I realised what was going on.

If you've already done this, the something is stopping it from running as the crescent moon says it's going into sleep despite knowing the handpiece is out of the cradle.

[tatel]

Your last picture seems to tell the story (the moon symbol). You must make sure the handpiece is seated and activating the reed switch when the unit is first turned on otherwise it'll never allow you to use it (just in case it's sitting out of the cradle).

It has an sticker on top saying it. Please see attachment. I'm doing so, handle is always on the cradle when station is turned on.

Can you check this? This stumped me once or twice until I realised what was going on.

When turning on, maybe a second after the initial big "beeeeep!", moon symbol appears.

By pressing any of the CH* buttons, it's gone; some five seconds later, it's there again.

Getting the handle out of the cradle has no influence over the moon symbol, it just remains there.

If you've already done this, the something is stopping it from running as the crescent moon says it's going into sleep despite knowing the handpiece is out of the cradle.

Yeah, bad luck, I guess.

[grantb5]

Apologies if this has been posted before, just saw this today. I don't own a hot air unit, but I am shopping for one:

https://www.tindie.com/products/randomhacks/best-bst-863-improved-control-board/

[pgo]

Hi,

A persistent problem with the unit I have is that the reed switch in the handle 'sticks'.
Tapping the handle will open it but it is not a good idea as the heater would be a bit vulnerable.
This is another thing to check.

I will get around to looking at trying to fix it eventually.

bye

[dreamcat4]

so then it would be nice to know the part number for a higher  quality replacement to order. that will also fit and be compatible (same sort of activation force). but perhaps with a higher durability etc.

so we can order and replace it. actually i already have to order some other parts from digikey soon

another good question is if we can install a 2nd reed switch and wire them up together for redundancy. if that is any possibility

[tatel]

so then it would be nice to know the part number for a higher  quality replacement to order. that will also fit and be compatible (same sort of activation force). but perhaps with a higher durability etc.

so we can order and replace it. actually i already have to order some other parts from digikey soon

Mine came with a spare one. 13 mm long, 2 mm diameter

[tatel]

FWIW, this is banggood's answer to my ticket:

Would you mind sending back the product for a replacement? Would you like to consider this solution? Here is return address： ATTN:EWORLDHOME LIMITED ADD: Dongguan Chuanjing electric machinery factory, No.20 Qinglong Road, Huangjiang Town, Dongguan City, Guangdong Province,China 523750 Mobile:15914368548 Could you contact your local post office to ask for the cheapest standard air register with tracking number? (please not send the items by DHL , UPS or EMS, it is expensive and easy to lead tax issue ) If the price is reasonable, we will send you another email with the return information.

The infamous return to China, even if it has been shipped from Spain. No way. I'm asking for a complete refund instead.

[dreamcat4]

This is why I use Paypal for payment method (or you can use a Credit Card too). In case there is need for using a chargeback. In fact there may also be a chargeback form supplied by your local bank for Debit Card payment too. But it's a longer process (more form filling)

[tatel]

I did use PayPal, but I'm not familiar with that chargeback thing. Could you please give me a link?

Anyway, I'm going to take it easy. 

[dreamcat4]

Paypal has it's own dispute resolution process which is effectively similar, their own equivalent of a chargeback.

Perhaps one way to start the process by logging into your paypal user account, then finding the transaction that corresponds to the sale. And there will be a link on the transaction summary to start the dispute.

Perhaps the other way to get there might be to first go into help / support, then find the resolution center. And then it should ask you to find the transaction from a list of recent transactions.

There are limitations to the Paypal system. Like maybe can only use it within a specific number of days time window. Like 45 days or something. Otherwise if you purchased an item thru ebay, then you cannot use the Paypal resolution centre for the transaction, and will have to use the ebay's own system instead. I really cannot remember now.

Anyhow you upload your message, with a description of the problem. Why they fell short. And usually a photo or 2 is also generally expected. (Which you already have taken). And wait some number of days for the dispute to go through.

Clearly the critical thing here is the unit is clearly faulty. As I questioned you about the fan at boot time. If it does not spin that's a definate fault. + the other symptoms too (basically it's never worked). So you read the manual, consulted with other more knowledgable users of the same device. And nothing worked / device never worked.

 

[DavidAlfa]

If there's no warranty sticker, I would have a look into the wiring and the board.
These kind of failures are usually simple things like solder short.

[tatel]

Well they are offering a full refund now. Well done, Banggood. I'm going to ask for some more details about it. Item has to be returned to China. Hopefully they will take return expenses. And I will probably ask for a working unit instead of any refund. We'll see.

No "warranty void" sticker. However, in my experience, DOA things are usually jinxed. I mean they are often faulty in more than one way. Maybe the workers had a very bad monday, or were drunk, or something. I do value my time, so I'm not willing to fight with microscopic solder craks, ESD damaged components, whatever. I paid what they asked for an item supposed to be good out of the box. So I want an item that works fine out of the box, even if I'm going to void the warranty immediately by changing the MCU board... even more so, because, should the mod go south, then I will know it's me who goofed it.