Ilford 1050 RC Print Dryer not heating

[mshchem]

View attachment 325349

This is mine currently.

That's a nice one. I would wager that you have corrosion on the heater ends. Just a basic connection current flows from on end to the other ( well in layman's terms) Again unplug the thing and go buy a cheap multimeter. You don't need power to check the heaters.
Google Ilford 2150 repair in the USA, these things are still around.

 

[mshchem]

BTW, Ilford hasn't sold or serviced this stuff for 15-20 years..

 

[Philippe-Georges]

It could be the 'thermal security' switch, sorry but I don't know the exact terminology in English for that little (automatic-) switch that protects the device for overheating.
That little 'thing' is mandatory in all heat generating devices, and switches off the heating when it 'feels' when the temperature is getting (to-) high, and the thermostat isn't reacting.
It looks like the thermostat is witching but it is exactly that 'thing', it switches back on after it is cooled down, that's why it can be confusing, but is isn't mechanically that strong and fails after a few times of switching.
Perhaps a native English speaking (handy-) person can explain it, and do the repairing, better than I ever could do...

 

[koraks]

@Philippe-Georges I'm fairly handy when it comes to electronics and have a pretty decent working knowledge of what kind of components are available, but I'm really struggling to figure out what you're talking about. All I can come up with is a thermistor, which is a PTC (positive temperature coefficient resistor) or a polyfuse. Polyfuses and thermistors are more or less the same thing, but neither protects a device from overheating per se. They present increasing resistance as current goes up. Thermistors generally do so quite gradually, while polyfuses are optimized for doing this rapidly as a specified trip current is reached, making them act similarly to a fuse - with the benefit that as they cool down, they revert back to a conductive/low resistance state. Polyfuses or thermistors are to te best of my knowledge not mandatory in any kind of equipment and have never been. I don't expect them to be used in this particular product as I don't think polyfuses with the required characteristics were available when these print dryers were engineered. In all likelihood these dyers use a regular fuse instead. It's conceivable that this dryer uses a separate fuse for the heating elements, although I'd be surprised if this were the case. It's easy enough to check as fuses are easy to recognize.

 

[Philippe-Georges]

@koraks, Sorry for my lack of knowledge of technical English...
But, I recall that the device I am talking about, could be found in TV's and radio's working with vacuum tubes, and it's in cars too where (unwanted-) heat can be generated in places like the dashboard, NOT in the engine bay.
It's in my glazing press too, near to the heating resistors, and it's not the thermostat, as it can't be tuned.
There is such a 'ting' on/near the circuit board of the microprocessor in my Colenta developing machine, it looks like a transistor, a bit larger, but it isn't one.
It's in my Multiblitz flash generators to, but there it has to be rest manually, and its not a fuse as it doesn't gard the current (Ampère) nor the tension (Volt) but specifically the temperature.
Actually, when the thermostat fails, that 'thing' cuts the current (or sounds alarm) when the temperature is getting too high, it's a safety device.
Long time ago, it worked with a bi-metal in an airtight glass or ceramic inclosure, but now it's more like an electronic/chemical sensor I think.

But, alas, I don't know the exact name of it in English, but I have seen it several times; in Flemish we call it a "thermiek" or a "thermische onderbreker"...

 

[fgorga]

It could be the 'thermal security' switch, sorry but I don't know the exact terminology in English for that little (automatic-) switch that protects the device for overheating.
That little 'thing' is mandatory in all heat generating devices, and switches off the heating when it 'feels' when the temperature is getting (to-) high, and the thermostat isn't reacting.
It looks like the thermostat is witching but it is exactly that 'thing', it switches back on after it is cooled down, that's why it can be confusing, but is isn't mechanically that strong and fails after a few times of switching.
Perhaps a native English speaking (handy-) person can explain it, and do the repairing, better than I ever could do...

I think the part you are referring to is called a "thermal fuse" or "thermal cutoff" in English.

 

[koraks]

@Philippe-Georges sorry, I don't know what you're referring to exactly. The combination of types of equipment, the thermal protection function and the possible regulation/mandatory nature doesn't add up to anything I'm aware of.
A collection of things could partially match your description, including thyristors in more modern equipment, EMI filter caps, PTC's, fuses and a couple more.
As you said, in old equipment a bimetal-based mechanical switch could be employed. The thing you describe in your Metz flash is fundamentally different by the sounds of it.

Anyway, it's all barely relevant to second guess based on dim awareness of what *might* be there. There *could* be a thermal protection circuit in there that might be the problem, in addition to a dozen more things.

For these dryers (and any device on general) it would help to have a schematic and some photos of the internals. Based on these it's usually possible to pinpoint some usual suspects for defects.
Nothing beats a few measurements in the device itself.

 

[BobUK]

Hopefully you will not find my advice offensive. I have the best intentions for your safety.

I don't want to throw a bucket of cold water on your enthusiasm but, from what you have said about not knowing what to look for, or how to test a fuse, I do not think you should be working on mains powered equipment without somebody who is competent looking over your shoulder and guiding you.
We all have to start somewhere and a safe start is best.

Talk with somebody competent in electronics or house wiring / repairs.

As to my own suggestion to a possible fault, bearing in mind that I have never seen a paper dryer like this, I am thinking along the lines of a hand held hairdryer.
Some hairdryers have a thermal fuse situated between the fan and the hot element. It looks like a glass bead with a wire coming out of each end and forms part of the circuit.
When the fan becomes clogged with bits of hair and fluff it slows down or stops revolving altogether.
When the fan is blowing strongly the cold air keeps the thermal fuse cool and all works well.
When the fan stops and the flow of cool air stops, the heat from the heating element warms up and the thermal fuse blows, breaking the circuit before dangerous temperatures are reached and, the hairdryer stops working.
There could possibly be a thermal fuse in between the fan and elements that has blown.

Explain that to someone that is knowledgeable enough to recognise the components and understand the testing of the parts.


Enthusiasm is one thing but, safety is prime.

Good Luck and a Happy New Year .

 

[henryyjjames]

@mshchem it turns out that one of the heaters in my 1250 is shot. The top one works but the bottom one doesn't. So now I have two print dryers to fix .

 

[mshchem]

@mshchem it turns out that one of the heaters in my 1250 is shot. The top one works but the bottom one doesn't. So now I have two print dryers to fix .

Do you have enough good parts to make one that runs?

 

[Philippe-Georges]

@mshchem it turns out that one of the heaters in my 1250 is shot. The top one works but the bottom one doesn't. So now I have two print dryers to fix .

What a relief that you found what's wrong, now you can look out for a repair!
And how wrong I was...

 

[koraks]

And how wrong I was...

1: It takes courage to admit one has been wrong.
2: Your hypothesis that it might be related to an overheating circuit was actually a useful one. I mostly debated the nature/technical implementation of that circuit, not the possibility of one malfunctioning if it's present. I should not have sidetracked the discussion as much as I did by doing so.

What a relief that you found what's wrong, now you can look out for a repair!

And that too

 

[henryyjjames]

What a relief that you found what's wrong, now you can look out for a repair!
And how wrong I was...

You still might be right; I actually have two different dryer models (1050 and 1250). I initially started this thread to solve the problem with the 1050 model, which wasn't heating at all. Then I discovered that the 1250 model only had one out of two heaters working. I think the fix for the 1250 is just going to be a replacement heater, but the 1050 is still unsolved.

 

[henryyjjames]

Do you have enough good parts to make one that runs?

I don't think so, the 1250 dryer takes two 450W heaters, and the 1050 dryer takes two 750W heaters— this is according to their respective manuals.

Also, the manuals list two separate voltages for both models, and from how I'm reading it, that means that there are two different versions of each model. Is it possible that the 1050 isn't heating up because it's not getting the right voltage? The power supply in my house 120V in each outlet. Maybe this is a stupid idea.

 

[henryyjjames]

This is the label that is on the 1250 dryer, which means that it must be the 120V version. Unfortunately, the label on the 1050 dryer is missing... looks like it peeled off a while ago.

 

[mshchem]

I would suggest that you see about finding a good electrician/electrical repair person. If the heater (s) are bad it wouldn't take 5 minutes to diagnose once removed.
These sorts of heaters were/are used in different areas. Much smaller versions have even been used in auto-defrost refrigerators to melt ice from the evaporator, seems illogical to put a 600W heater inside a refrigerator, but especially in the US it's nearly universal. Should be called a food dehydrator, but I digress.

When you get an arc from household current metal is often melted and blasted into an unprotected person's face. Bad news.
I think these are supposed to have a switch that disconnect the power when you open the upper part