ST-862D 110v Shipped instead of 230v  - Page 1
Forum section: electronics / general

author: simonboydfoley
author_rank: Contributor
timestamp: August 23, 2024, 07:33:53 pm
content: Hi Guys,anybody here with better knowledge of transformers than me know if this Unit will work in the UK ?The transformer in the unit is a EI-66*28 and it clearly has an input label that states 110V/60Hz .I have managed to track down this site .... but it does not mention if there are specific models for different input voltages of it can cope with either 110V or 230V.https://www.powersupplytech.net/low-frequency-transformer_p_394.htmlIn the manual it states its supports 230V 50Hz .. then in brackets (Optional 110V 60Hz)Which I don't know if it means the 110V version is a different part to be ordered optionally or if the transformer is designed to be able to cope with 230V and can also cope with 110V.I'm googling how transformers work now :-)

author: edavid
author_rank: Super Contributor
timestamp: August 23, 2024, 07:51:14 pm
content: It won't work, and it would be dangerous to plug it in to 230V.You need to have them send you the 230V version.

author: simonboydfoley
author_rank: Contributor
timestamp: August 23, 2024, 08:31:32 pm
content: Thanks appreciated for the feedback.I assumed that most manufactures these days would fit switchable Transformers between 110V/230V so I specifically asked for the 230V Version in the order notesIronically I ordered from NorthridgeFix to try to support their channel even though it shipped all the way from CA USA to UK.You would think that they would know this basic 101 being electrical engineers with an international shop!I'm now in a dilemma ... they clearly made a mistake;1). Shipping a US 110V Unit to a UK Address.2). Not reading the order notes.I have spent $81 on shipping and $89 on import tax, for a $265 unit.Ethically I feel its environmentally wrong to ship this back to them as we all loose.As a good EEV Blogger I should man up and source and fit a replacement transformer suitable for a 230V Source supply....... #researching ....

author: simonboydfoley
author_rank: Contributor
timestamp: August 23, 2024, 09:37:59 pm
content: Hummm .... good educational SNAFU this .... trap for young players, posting so we all learn.So it seems a transformer is just a simple inductor where the input and output voltages are determined by the differential windings of a pair of coils.the ratio of windings between the input and output determines if it is a step up or step down transformer.Most transformers are step down transformers in domestic power supply's .So ... working this out in my headStep Down Transformer: The input coil has more windings than the output coil => Voltage Decreases (steps down) from the Src and current increases.Step Up Transformer: The input coil has less windings than the output coil => Voltage Increases (steps up) from the Src and current decreases.It looks like its no coincidence that US Power supplies are 110/120v which is half the rest of the world 230v/240v.So manufactures can ship the same transformer in all their products that is a 230/240v version designed to create the voltage/current needed for their PCB's.And if it happens to ship to the US ... they simply "wire in" a terminal instead of half way down the output coil that drops the output voltage by 50% on a 230V src supply .... to the full extent of the coil on a Src voltage of 110V to achieve the same effect,This is what those switches on the back of Commercial appliances do when they give the consumer the option to select either select 110V or 230V by moving a switch on the back of the unit.... they simply flip the output coils location from the middle (230v Src Voltage) on a to the end of the coil (110v Src Voltage)... while it looks like its not exactly half'ing documented output voltage or doubling the output current=> the PCB has tolerances to be able to cope with deviations in the range +/- 10V and +/- 10Hz (50Hz vs 60Hz differences between "Rest Of the world" and US Power sources respectively) as well as deviations in Current and Voltage in a countries regional power system.So .... I am thinking ,,,, until I find better data sheets of the "Ei 66*28 power transformer" it seems to be rated to 230V... which suggest that they have simply saved costs (Munced) the back of the unit by not putting a switch that flips from the units half and full coil position.All they have done is use the same transformer for both US and Rest of the world units ....US Version: Transformer Output Wire to the PCB Bridge rectifier is the full extent of the coil.Rest of the world version : Transformer Output to the PCB Bridge rectifier is only half way of the output coil.So tongue at the side of the mouth ..... technically I am wondering if all I have to do is de-solder the output wire on this US Version of transformer from full coil output terminal position to the half way position.I need to inspect the transformer in the unit to see if it has 2 out put terminals for the output coil position.It may not make economic sense to source 2 different transformers for US (10% market) and Rest of the World (90%) for their units so this has a high probability of being a successful assumption.### Now ... next problem .... Current ###If the US Transformer is using the full coil to get the desired output voltage (which I think is 9-12V AC to the PCB's Bridge rectifier) ... and then I move it to the half way output terminal.I may get the desired output voltage ..... but the current output is inversely proportional to the voltage decrease. So by using half the coil I may be doubling the current supplied to the PCB by making this change.... so I am thinking that there maybe a resister on the PCB before the bridge rectifier that also needs to be replaced to reduce the current supply... or its been hard wired into the different output terminals of the transformer to provide a consistent output voltage and current for US vs rest of the world input supplies to make it easier for the customers to implement.Wow if I am close to understanding the situation ..... its down to 5 years of watching Mr Chicken Dinner himself on you tube !#needmoredata on the Transformers specificationsUpdate: If V = IR => the resistance of the Bridge recitifer +PCB will always be the same ... if I get the same voltage to the PCB ... there will be no need to swap out any resistor as the circuit will pull as much current as it needs.While the available current may be double on a UK Power supply using the same transformer at the half way position ..... its just that "available"... wont be a problem in the UK as what is available current is always grater that what the PCB will draw as as the PCB has to be rated to draw no more than 50% the current in the rest of the world provides when it is used in the US market!

author: edavid
author_rank: Super Contributor
timestamp: August 23, 2024, 10:15:26 pm
content: I don't understand what you are saying. A dual voltage transformer has 2 identical primary windings, which are put in series for 230V, or parallel for 110V. If you post a photo of the transformer in your unit, we can tell you if it's dual voltage (unlikely).Please note that even if you deal with the transformer, the heating element will probably also be for the wrong voltage. (Maybe other parts too.)I don't know why you would make it your problem when the seller obviously messed up. They should ship the correct unit at no cost to you, and deal with the return shipping if they want the 110V unit back.Otherwise I hope you paid with a credit card, so you can do a chargeback.

author: thm_w
author_rank: Super Contributor
timestamp: August 24, 2024, 12:05:21 am
content: A hot air station will not work with the wrong voltage unless the transformer and heater coil are replaced. As edavid says.Both parts can be bought, total cost is about $60:https://www.aliexpress.us/item/3256803260089068.htmlAsk them if they want it shipped back, at their cost, or maybe can give you a $80 refund or something.IMO just send it back and get a full refund and buy the right thing from somewhere else. ~$175 with free shipping if you use coupons:https://www.aliexpress.us/item/3256805996293243.htmlIn the future if you like a youtube channel just donate to them directly.

author: simonboydfoley
author_rank: Contributor
timestamp: August 25, 2024, 03:14:14 pm
content: Yes Apologies I massively miss understood how the power circuitry would be implemented in these units.I assumed that if you have a primary coil and a secondary coil set for a step down transformer to the required voltageI thought all you would need to do to be able to cope with 110v & 230v input voltage would be to have a terminal midway off the secondary coil and one terminal at the end of the coil (effectively 2 coil in series).Input Voltage = 110V Secondary Coil => Use the end terminal (2 coils in series) and you would get the desired output voltage.Input Voltage = 230V Secondary Coil => Use the midway terminal (1st Coil Only) and you would get the same desired output voltage as the secondary coil has double the input voltage of the src but half the coil, ergo same output voltage.Turns out this is much a more complex power set up and design .... but my understanding of the principle seems correct...... see attached photos.In essence the Transformer has multiple input and output coils generating different output voltages ... and they are *all* needed by the PCB.## My uneducated understanding of the layout ###1). AC to front ON/OFF switch then to what looks like an AC Input voltage is taken through a filter (The separate PCB with a large choke? not sure yet).2). From the filter it then goes to the PCB and and then straight back out again to the transformerI assume its just passthrough but there must be a reason they did not simply wire directly to the transformer.3). On the Transformer it seems there are 2 input Coils and 3 Output coils.Input Coil 1: 7v/200mA Output Coil: 1 x 24v ( I don't quite understand the 2nd Input Coil yet (7v/299mA) I need to do some more research)Input Coil 2: 110v/50Hz 1st Output Coil: 1 x 9v2nd Output Coil: 1 x 18vAs all the output coils are in use .... I have no options.I also assumed that the PCB and heater elements would be the same on all US and Non US Models .... but that could be wrong as well.This unit looks useless outside of the US and I cant fix it.

author: simonboydfoley
author_rank: Contributor
timestamp: August 25, 2024, 05:29:11 pm
content: Now I am getting a little confused.1). I asked for a 230V version in the order notes.2). I checked a PDF Version of the manual and it said it was optional 230v/110v.3). When I double checked NorthRidgeFix's listing again ... they also said 110v/230vBut when you look on the back of the unit ... and the transformer ... It all states input voltage to be 110v 50HzMaybea). it was switchable input voltages at one point ... then Atten changed it to save some money and NortRidgeFix didnt pick up the changeorb). NortridgeFix simply screwed up and sent a 110v version when they have 230v versions in stock.orc). The unit is switchable 110v / 230v and that PCB I thought was a filter is an autodetect stepdown transformer that drops the voltage to 110v AC if it detects 230v.In which case why would the label on the back of the unit not indicate its "110v / 230v" and not just "110v" ?!?! Nahh those are deffo High Power capacitors and its a inductor filter/choke so it looks like its there to smooth any noise in the power input before hitting the Transformer.

author: simonboydfoley
author_rank: Contributor
timestamp: August 25, 2024, 06:01:36 pm
content: Yup ,..... I double checked Atten's website and even for the US Landing Page ... they all show the same image .... The Non US version with the a 230v label... there is no switchable unit.Its a different product version for 110V and 230vThis is clearly a NorthridgeFix f*** Up.There is no other way I can remedy this problem cheaply .... its an 1000w unit .... cheapish UK/US transformers are only rated 45w - 100w.Shame for all that carbon shipping waste and extra import tax just to try to support a youtube channel :-(I have had to order a 230V version from a local supplier as I have a project to complete and I cant wait any longer.I'll try to get my money back off NorthRidgeFix and get them to pay for shipping as it was their screwup.Thanks for everybody's help.

author: simonboydfoley
author_rank: Contributor
timestamp: August 28, 2024, 08:41:49 pm
content: Update: For teh recordMy New unit turned up today ..... you can clearly see the different Step Down transformer Transformer from the US version.