Calling electronic experts

[voipio]

The 25z 9727 part, 4 images back, is actually a 2.5V voltage reference, part number REF25Z.

The triac is most likely mounted on a heatsink, especially if it is controlling a heater load in excess of several hundred watts.

What are the markings on the actual body of the device mounted on the heatsink?

 

[dannyp]

i usally look for things with heatsinks but tbh with power electronics they tend to work or not work usally changing operational state with a stink or bang, id look at thermocouples probaly k type and cheep and they do go bandy

 

[ukracer]

The 25z 9727 part, 4 images back, is actually a 2.5V voltage reference, part number REF25Z.

The triac is most likely mounted on a heatsink, especially if it is controlling a heater load in excess of several hundred watts.

What are the markings on the actual body of the device mounted on the heatsink?

THat I cant tell you yet... I need to wait till everyones in bed to get soldering station out! Need to remove the heat sink to get at the markings they are between the heat sink and transformer

 

[ajlelectronics]

If all else fails, I could probably design you a new controller complete!

 

[ukracer]

i usally look for things with heatsinks but tbh with power electronics they tend to work or not work usally changing operational state with a stink or bang, id look at thermocouples probaly k type and cheep and they do go bandy

I feel that also but my real world experience is with soldering up valve amps designed by a mate and I started as an electronics technician working on the BSR Acutrac. I was really a glorified fitter...lol so I can solder but dont know much about the working of the actual parts.

I am wondering if the adkins guy got upset when I said no way am I paying 450 notes for a service and spare part when it nearly works and I can change parts at component level.
Either way if he was giving me a bum steer away from thermistor or the real likely problem its out of order as he said he was almost certain it was the controller board BUT most likely needed a loom change. Either way his MD wont be happy when I get it fixed. I dont mind if he said its not company policy to assist end users with board level components......but if he has led me astray I wont be happy!

 

[ajlelectronics]

Well as everyone else has said, a triax will either work, or dispense magic smoke. If the temperature is unstable, it points to a sensor issue. Do you know where it is? When the temperature overshoots, you could try blasting it with a hair dryer to see if it will shut down the heater.

 

[ajlelectronics]

When the temperature overshoots or comes on uncommanded, does the display show the actual temperature of the heater or somewhere nearby?

 

[dannyp]

thats typical low volume manufactuer advice, "it's the board mate" to be fair to them in a lot of manufactuer diagnostic routenes the board is the first thing you check but thats because they've got spares / one in the tool box and its an easy way to elimanate the most complex thing then you test the inputs / outputs

if you have to buy the most expensive part to confirm it's not that i go the other way round, used to get it with a lot of machenary it was allways the board only on 1 particular machene was it ever allways the board well it was allways the 12v regulator that failed that inturn killed the 5v regulator and was allwasy due to a broken down selonoid coil, my personal record to get machene back online was under 90 seconds ( there was some luck involved in that and prep of pre heated soldering iron

 

[ukracer]

View attachment 216135 View attachment 216136

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.

 

[ukracer]

When the temperature overshoots or comes on uncommanded, does the display show the actual temperature of the heater or somewhere nearby?

I wrote this on the sublimation forum.

The reply I got from another user is below.
*******************
Anyone have an Adkins Beta press badged as The magic touch. Mine seems to be playing up but its random.
Sometimes it seems fine.
Other times it heats and and does not stop at the temp that has been set.
Other times it seems to sit at the temp it was at when I turn it back on. For example I set it at 165 and it goes up to 180 so I switch it off and wait. I turn it back on and its at 155 but it stays there and does not get to 165 or go past to 180 again.


This was the reply.

I’ve got one & mines got the same issue. I rang Adkins & was told the controller boards probably on its way out. it’s approx £150 plus vat to replace. They said it’s not difficult to change. I’m going to wait until mine gets worse. Adkins advised me to turn it off & then when I turn it back on set it go a low heat & gradually build it up to the higher heat. It seems to work for me & ive not had a problem for about a month now x

So it seems like a regular fault......

 

[ukracer]

Well as everyone else has said, a triax will either work, or dispense magic smoke. If the temperature is unstable, it points to a sensor issue. Do you know where it is? When the temperature overshoots, you could try blasting it with a hair dryer to see if it will shut down the heater.

This was my thoughts. I have had to change the thermistor in 3d printers and to be fair a heat press is only an expensive 3d printer where the bed is more robust and gets hotter to be fair.

 

[ukracer]

thats typical low volume manufactuer advice, "it's the board mate" to be fair to them in a lot of manufactuer diagnostic routenes the board is the first thing you check but thats because they've got spares / one in the tool box and its an easy way to elimanate the most complex thing then you test the inputs / outputs

if you have to buy the most expensive part to confirm it's not that i go the other way round, used to get it with a lot of machenary it was allways the board only on 1 particular machene was it ever allways the board well it was allways the 12v regulator that failed that inturn killed the 5v regulator and was allwasy due to a broken down selonoid coil, my personal record to get machene back online was under 90 seconds ( there was some luck involved in that and prep of pre heated soldering iron

Yes I used to repair vinyl cutters. As the boards were all made in china I would start by putting in a known working board. Test it and if it fixed the fault I would take it back out and put a new one in.....keeping the known working one as a test. Occasionally I would put a new board in that failed........because the new ones had a 10% failure.
But the boards were only 20 quid retail. Hardly with getting a soldering iron out.....even if it were suitable. The boards were all double sided surfaced mounted.

But the two boards in the press have few components to fail. Lol

 

[ajlelectronics]

It doesn't look very sophisticated to me. One advantage you have is that it doesn't seem to use "house numbers" There are bog standard, off the shelf components on there, so even a "scattergun" approach may resolve it, as long as you can prove the temperature sensor is OK (I bet it isn't).

It may look like a lot of components, but then so does a car. Break it down by function...
Your press consists of a heating element, a thermostat and a timer which display on a 7 segment device. Therefore you can isolate the problem to a handful of components. You know for instance that the timer is OK? You know that the heating element is OK? Etc. I didn't see a custom IC on the board either which helps, unless I missed it.

 

[voipio]

The code for the controller is probably running on the device that has a label on it, the device being some sort of PIC or similar microcontroller. The LTC1025 is for thermocouple cold junction compensation, the LT1006 is a precision op-amp, so probably associated with amplifying the thermocouple signal. Most of the other parts form some sort of logic or buffering function e.g. display driving.

 

[Alan Reynolds]

This is the exact one that I always find has the dry joints on the connectors. Get a jewelers loupe X3 is a comfortable magnification and just go round and look for fine cracks around the connector pins.

 

[ajlelectronics]

The code for the controller is probably running on the device that has a label on it, the device being some sort of PIC or similar microcontroller.

Yes, right before my eyes, and didn't see it! However, it is unlikely to be faulty.

 

[ukracer]

This is the exact one that I always find has the dry joints on the connectors. Get a jewelers loupe X3 is a comfortable magnification and just go round and look for fine cracks around the connector pins.

Alan when you say exact one. Do you meant exact heat press board or exact connector?

Just had an update as I ring Atkins again. It's the triac hidden behind the larger or the two heatsinks.
When I suggested triacs usually just work or don't the response was we don't actually make or repair the boards her (which I strongly suspected).

My uneducated guess is those of you mentioning dry joints are potentially nailing it but changing a triac would also repair a dry joint on the triac pins..

 

[Hopefuldave]

Alan when you say exact one. Do you meant exact heat press board or exact connector?

Just had an update as I ring Atkins again. It's the triac hidden behind the larger or the two heatsinks.
When I suggested triacs usually just work or don't the response was we don't actually make or repair the boards her (which I strongly suspected).

My uneducated guess is those of you mentioning dry joints are potentially nailing it but changing a triac would also repair a dry joint on the triac pins..

Where the current's highest and dry joint most likely...

Dave H. (the other one)

 

[Alan Reynolds]

Alan when you say exact one. Do you meant exact heat press board or exact connector?

Just had an update as I ring Atkins again. It's the triac hidden behind the larger or the two heatsinks.
When I suggested triacs usually just work or don't the response was we don't actually make or repair the boards her (which I strongly suspected).

My uneducated guess is those of you mentioning dry joints are potentially nailing it but changing a triac would also repair a dry joint on the triac pins..

Yes, that exact one. board and all. My daughter's old boyfriend set up his own print works and would buy secondhand/faulty presses and I would repair them. They're not economical to repair when the heating plate goes but other than dry joints and turning up new bits that wear on the handle pivot they are reliable. I've even made new bars and bearings for the sliding plates as I have a suspicion they are made in India and their welding leaves a bit to be desired.

 

[ukracer]

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

Which is the best to get out if all those.
I am just about to order triacs and going to add some solder..
I used to have rolls of very thin stuff which was awesome.