Huge Longshot! if anyone could identify the components

Ian0

Joined Aug 7, 2020
3,766
On the underneath view, the circuitry at the right is an offline power supply, using, at a guess, one of On-Semi's IC's
https://www.onsemi.com/products/pow...=fi0xMX52YWx1ZX4xflNPSUM4IE1JU1NJTkcgUElOIDN+
or something with a high-voltage supply on one pin (hence the gap)
The 0.65mm pitch IC at the left is probably a microcontroller, because it has a crystal attached.
Once you have paid your £3000 to reverse engineer the board, are you going to pay another £3000 to reverse engineer the software?
There are scores of application circuits on manufacturers' websites for small off-line switched-mode power supplies that you can use for FREE!
 

Thread Starter

Moondog67

Joined Jun 25, 2021
10
Thx for the replies!

I am definitely trying to implement the boards function rather than have it reverse engineered.

Which is why I wondered if I could submit the board and spec for fabrication for a fraction of the cost...but I obviously need to know what to order. As stated in the title, this is a huge long shot, im trying to save myself a few quid...the board is actually from my pool filter/heater/chlorinator...it set me back £1200 and is only just out of warranty!

I've spoken to the manufacturer (intex) and they don't replace the part in question...my only option is to but the main pump/heater assembly...which is £900 on its own...

It seems silly to fork out those sums of cash, when the fault is with a part that costs pennies...I just don't know enough to get this made...hence, im here being an annoying newbie.
 

Ian0

Joined Aug 7, 2020
3,766
A word about warranties: Under the Consumer Rights Act 2015, to paraphrase and simplify: Your rights lasts 6 years. For the first 6 months, the supplier has to prove you broke it, for the remaining 5½ years you have to show that there was a deign or manufacturing defect when it was supplied; and if you have done nothing other than use it as installed and it only lasted 12 months and a day, then that would imply that it wasn't designed to last. £900 for a new part makes a county court writ look cheap at £50, and the supplier would probably not want to defend it.
(But don't take legal advice from an engineer - ask https://www.citizensadvice.org.uk/)
 
Last edited:

Yaakov

Joined Jan 27, 2019
3,755
As previously mentioned, reproducing the board is relatively trivial compared to reproducing the code.

You would be as well off starting from scratch if you don't have access to the source code for the device.
 

Ian0

Joined Aug 7, 2020
3,766
What does it do? I can see mains input and a relay-switched mains output, a small switched-mode power supply, a buzzer and a couple of low-voltage inputs, one on pin-headers and one on a small Molex socket. Assuming about 50p each for the relay, microprocessor, switched mode controller, and hf transformer, put together on a cheap paper board, altogether about £4.
Could you replace it by a 6A light switch, and just turn it on when you think it needs it?
 

BobTPH

Joined Jun 5, 2013
4,051
What did the board do originally, and what is wrong with it now? Repair is not completely out if the question, a description of what is wring might suggest a simple fix.

Bob
 

Ian0

Joined Aug 7, 2020
3,766
Looks like the most cheaply made little switched-mode to me - so I bet that's what has failed. I also don't see any interference suppression, and I wonder how well it is working without its class-Y capacitor! (CY1 on the Pcb)
Usually, the IC fails and the output voltage just disappears, which protects anything on the secondary side, and it's a pretty good bet that what is on the output still works.
 

Thread Starter

Moondog67

Joined Jun 25, 2021
10
Thx again for your replies!

As mentioned this is the pcb from my pool pump. The control panel on the pump is just a simple on/off switch with a timer. There is a simple numerical lcd display.

I tested with a volt metre and its receiving the correct voltage. However the terminals that feed from the board to the motor are completely dead. You can see from the underside of the board that one of the chips is burnt out. We woke up one morning and the main rcd had tripped and this was 100% the cause. There's no way any water got in as its waterproof.

Thx for the info regarding consumer rights! This is something I will definitely look into.

Thx again
 

Ian0

Joined Aug 7, 2020
3,766
Is it the 4-pin device that has failed (bridge rectifier)? I see some soot around it.
If that failed, and the switched-mode IC (8-pin with one pin missing) didn't fail, then it can only have been because it was unable to cope with the inrush current.
However, if it was the bridge that failed, it is easily replaced. I also think that there is a fuse (f1) on the other side of the board. It would be interesting to note if that had blown.
 

Thread Starter

Moondog67

Joined Jun 25, 2021
10
What did the board do originally, and what is wrong with it now? Repair is not completely out if the question, a description of what is wring might suggest a simple fix.

Bob
Its
Is it the 4-pin device that has failed (bridge rectifier)? I see some soot around it.
If that failed, and the switched-mode IC (8-pin with one pin missing) didn't fail, then it can only have been because it was unable to cope with the inrush current.
However, if it was the bridge that failed, it is easily replaced. I also think that there is a fuse (f1) on the other side of the board. It would be interesting to note if that had blown.
Yes its definitely the bridge that has failed. I suspect something large blocked the pump intake for a short time and caused it to run dry.

You mentioned an easy repair. Are we talking soldering iron and magnifying glass and average at best soldering skills?

Thank you
 

Ian0

Joined Aug 7, 2020
3,766
Yes its definitely the bridge that has failed. I suspect something large blocked the pump intake for a short time and caused it to run dry.
Actually no, the pump current doesn’t go through the bridge. It is most likely bad design, specifying the bridge without allowing for the capacitor inrush.
There should be protection circuits to deal with an over.lad caused by a blockage, at least a fuse. It should never result in component failure.
You mentioned an easy repair. Are we talking soldering iron and magnifying glass and average at best soldering skills?
exactly
 

Thread Starter

Moondog67

Joined Jun 25, 2021
10
Actually no, the pump current doesn’t go through the bridge. It is most likely bad design, specifying the bridge without allowing for the capacitor inrush.
There should be protection circuits to deal with an over.lad caused by a blockage, at least a fuse. It should never result in component failure.

exactly
Would the power that feeds the c/panel go through the bridge? As the display is dead.

So I guess the next question is, where can I source a replacement part? And how can I be sure its the right part? As mentioned before I am a complete newbie. I really appreciate your help
 

LesJones

Joined Jan 8, 2017
3,571
I think there has been a flashover on the etch side of the board to the right of the bridge rectifier. If this is so then this was probably the original fault that caused the damage.
I have added a flipped version of the etch side to make it easier to match with the through hole component side.

250621.jpgThis is one possible replacement for the bridge rectifier. If you replace any components I suggest initially applying power to it via a old fashioned tungsten filiment lamp of about 60 watt rating to limit any fault current.

Les
 

LesJones

Joined Jan 8, 2017
3,571
Hi Ian, I am looking at the discolouring of the board to the right of the top right pin of the rectifier (Picture post #17) It may be just corrosion or a coating on the board. It looks like there is a coating on the board around the switch mode regulator IC (U2)

Les.
 

Thread Starter

Moondog67

Joined Jun 25, 2021
10
I think there has been a flashover on the etch side of the board to the right of the bridge rectifier. If this is so then this was probably the original fault that caused the damage.
I have added a flipped version of the etch side to make it easier to match with the through hole component side.

View attachment 242130This is one possible replacement for the bridge rectifier. If you replace any components I suggest initially applying power to it via a old fashioned tungsten filiment lamp of about 60 watt rating to limit any fault current.

Les
Thank you Les! I have ordered the part you provided the link for.

I noticed with the other 2 chips, there is a silicone dab protecting them. Should I do the same once I've installed the new bridge? Thinking it might insulate the area better.

Thank you very much
 
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