Calling electronic experts

[ukracer]

I have a heat press and it heats up randomly.
Sometimes it's fine.
Sometimes it fails to stop at the temp set.
Other times if it's turned off to lower the temp to below pressing temp, it fails to heat up and sits at a lower temp.

Upon speaking to the supplier they inform me it needs a new 150 quid control board and a new loom and a service.......total cost approx 450 quid plus vat and carriage.

But he let slip it's probably only a 3 quid triac but would not tell me which one.

So I stripped it down and looked for a triac.
I can only see one on possibility on the controller board.
I can see one on the other board labelled triac 2. Which suggests it might not be the only one. But do triacs have heat sinks?

 

[Alan Reynolds]

I would expect a component like a triac to either work or not work. I would take a VERY close look at the solder connections on the plugs on the pcb.

Also look at the solder joints on the components like the triacs. I've been asked to look at heat presses and they have always had dry joints on the plugs and higher current components.

 

[Rayf]

The advice re solder joints, is worth dealing with before you start replacing parts.
I suggest you get a good quality soldering iron and some good old 60/40 lead solder, and reflow all of the joints, could be a cheap fix.
Avoid the lead free solder, it's the work of the devil.

 

[ukracer]

I would expect a component like a triac to either work or not work. I would take a VERY close look at the solder connections on the plugs on the pcb.

Also look at the solder joints on the components like the triacs. I've been asked to look at heat presses and they have always had dry joints on the plugs and higher current components.

Why would an engineer suggest it might be a triac......when it's very like not if the work or don't.
This company was always meant to be very helpful....but I guess at 500 quid a pop for a phone diagnosis....that can't be accurate they can afford to be helpful.

 

[Alan Reynolds]

Triacs could well have a heat sink, especially feeding a heater element. I can't see that board being worth anywhere near £150 plus vat.

 

[ukracer]

The advice re solder joints, is worth dealing with before you start replacing parts.
I suggest you get a good quality soldering iron and some good old 60/40 lead solder, and reflow all of the joints, could be a cheap fix.
Avoid the lead free solder, it's the work of the devil.

I have a hot air solder station as well as irons. And I hate lead free.....but my stock from 1976 has run out now.

 

[armalites]

On a board like that you could probably reflow every joint in half an hour easily. I suspect they replace the triac but the act of resoldering is actually what fixes it. It's possible they put a higher spec one in too.

 

[snoozer]

At the price of a new Triac I'd replace any I could find, Your bound to get the right one !

 

[ukracer]

Triacs could well have a heat sink, especially feeding a heater element. I can't see that board being worth anywhere near £150 plus vat.

That was my reaction.....the only possibility I can see on the controller is this.

25z 9727 does not bring anything up in Google that fits



The one listed triac2 I could change but there is a 3 pin package on the back of the large black heat sink at the front but it's labelled What looks like LCI 98- something 4.

 

[the snooper]

As said triacs work or they don't, as the heat is all over the place I'd be looking at a faulty thermostat or thermistor

 

[ukracer]

At the price of a new Triac I'd replace any I could find, Your bound to get the right one !

Well I did think that but not sure which ones are triacs. Lol

 

[the snooper]

That was my reaction.....the only possibility I can see on the controller is this.View attachment 216116

25z 9727 does not bring anything up in Google that fits



The one listed triac2 I could change but there is a 3 pin package on the back of the large black heat sink at the front but it's labelled What looks like LCI 98- something 4.View attachment 216118

The one in your first pic is a small transistor

 

[the snooper]

Well I did think that but not sure which ones are triacs. Lol

Triacs are 3 pin and are or have the ability to mount on a heat sync

 

[ukracer]

As said triacs work or they don't, as the heat is all over the place I'd be looking at a faulty thermostat or thermistor

My thought was thermistor but that was not even suggested by Adkins.
They do provide decent documentation. (Better than most to be honest) but why not be honest when I phone and ask.
https://aadkins.com/wp-content/uploads/documentation/BETA-MAXI-MINI-MANUAL.pdf

 

[ukracer]

The one in your first pic is a small transistor

I thought that but someone suggested it may be a triac. Lol

 

[the snooper]

I thought that but someone suggested it may be a triac. Lol

I thought that but someone suggested it may be a triac. Lol

It does show a probe in the diagram, with a triac they usually fail altogether, they are used alot in lighting controllers for switching

 

[zx9]

And I hate lead free.....but my stock from 1976 has run out now.

You can still buy solder containing lead, just not for commercial use.

https://cpc.farnell.com/c/tools-maintenance/soldering/solder/prl/results?solder-alloy=60-40-sn-pb

 

[HughF]

If you want me to reflow it just send it down and cover the return postage, I'll go over it with a magnifier and check out any solder joints. If you have a test procedure and a test circuit I can probably test it for you too if I get a spare couple of hours on evening at work...

 

[anjum]

I would go with the suggestion of resoldering all joints on the boards, especially the power board and especially the contacts under the screw connectors and the power triac.
All sorts of possibilities for the problem! check the probe is connected and firmly in contact with whatever it should be measuring.

Also check the earth connections at the star point (if the exploded diagram is correct)

Triacs can be all sorts of shapes and sizes, some are even 6 pin ics to isolate low voltage from high voltage.
You may be able to trace the tracks from the main triac on the power board, two of the leads will go to the power. One, the base or trigger should go to the control board and most likely to the other triac/ diac.

 

[ukracer]

I would go with the suggestion of resoldering all joints on the boards, especially the power board and especially the contacts under the screw connectors and the power triac.
All sorts of possibilities for the problem! check the probe is connected and firmly in contact with whatever it should be measuring.

Also check the earth connections at the star point (if the exploded diagram is correct)

Triacs can be all sorts of shapes and sizes, some are even 6 pin ics to isolate low voltage from high voltage.
You may be able to trace the tracks from the main triac on the power board, two of the leads will go to the power. One, the base or trigger should go to the control board and most likely to the other triac/ diac.

That's a bit more worrying. Loads of iCs on the controller board.

If you want me to reflow it just send it down and cover the return postage, I'll go over it with a magnifier and check out any solder joints. If you have a test procedure and a test circuit I can probably test it for you too if I get a spare couple of hours on evening at work...

Could end up taking you up on this mate. I do have a hot air machine and plenty of soldering irons but I know you are damn good at what you do. As for testing I can't see that being easy as some of it is a very heavy Platten etc