Old resistors with thermal insulation?

[Doomguy42]

Hi can anyone tell me what type of resistors these are? There are used elsewhere and split in pairs in the circuit so x2 at half value. The leads are mighty. I guess the application for them to minimise heat getting back into the board?

I was looking at replacing them all like for like or a better resistor for the job if there's anything modern or newer?

Thanks

 

[rjenkinsgb]

They just look like normal wire-wound resistors. I'd not bother replacing them unless the coating has cracked off or they have some other defects.

I suspect the long leads are to maximise airflow around them, rather than it being restricted by proximity to the PCB.

If you do replace them, you can just leave the new ones stood off at around the same height. I can't recommend specific parts without knowing the dimensions and values.

The rigid lead ones in use would just be quicker to assemble in mass production.

 

[Nigel Goodwin]

Hi can anyone tell me what type of resistors these are? There are used elsewhere and split in pairs in the circuit so x2 at half value. The leads are mighty. I guess the application for them to minimise heat getting back into the board?

I was looking at replacing them all like for like or a better resistor for the job if there's anything modern or newer?

Thanks

Why on earth would you be looking at replacing them?, they look like perfectly fine, high quality, wire wound resistors - they almost certainly won't be faulty - and anything you replaced them with would most likely be inferior.

It's also not thermal 'insulation', it's something like cement (because it won't melt or burn) to keep the windings in place.

As already said, the length of the wires is to keep the resistors spaces off the board, to allow better air flow, and to help protect the board from heat damage.

 

[crutschow]

Here we have an apparent example of "part shaming".
He wants to replace them because he thinks they look old and bad.

 

[Doomguy42]

Haha thanks gents. I'm smarter than that. The board I'm working on has conventional resistors fitted but raised up... these have nasty corrosion underneath which looks like flux damage.

I have to take these off anyway. To clean up the board. The area I have removed these are corroded too see picture.

The types more common to these board look much better, more robust, better heat disapation through the big leads. I was asking on the type of resistor I'd much rather use this type.

 

[Doomguy42]

This is one pulled from the bare area... can you see why I'm not happy with them

 

[Doomguy42]

This type is used 99% of the time on the boards ive seen.. I've never needed to buy any so genuinely was just asking what type of resistors they are? I would much rather use these if possible rather than the usually resistors and jack them up high.

If it's a stupid question I don't know why so someone will have to explain?

 

[Doomguy42]

Here we have an apparent example of "part shaming".
He wants to replace them because he thinks they look old and bad.

Here's a better picture for you to decide

 

[rjenkinsgb]

They are generally similar in appearance to TE FC series - but you have still not given the dimensions or values etc., so it's still total guesswork!

https://www.te.com/commerce/DocumentDelivery/DDEController?Action=srchrtrv&DocNm=1773215&DocType=DS&DocLang=English

 

[Doomguy42]

Superb thank you very much

 

[Externet]

From the added pictures of 'other style resistors' like post #6, I would say they look in the same or better condition, and the comment of 'corrosion' is not correct.
It is just not modern components you may have not seen often perhaps by your young age. Their removal may have jeopardized the integrity of solder pads and traces.
I would carefully put them back consciously. They appear from times things were made much, much better; should be far more reliable than modern cheap or chinese components.

 

[Doomguy42]

Yeah in post 6 that resistor isn't corroded. It's a reference picture of a component I've pulled from one another dead board to show want I want to use.

The other pictures do show resistors from boards with clear corrosion, I'm working with corroded boards which needs repairing.

Try to understand this...I'm experienced enough to know if and why I want Replace and repair corroded area of a board. My soldering is great...no I'm not going to damage anything pulling corrode components off.

Honestly I think telling people to leave corroded 27 year old components Alone is AWFUL advice.

The question I was asking is what type of resistors they are?

 

[Nigel Goodwin]

Yeah in post 6 that resistor isn't corroded. It's a reference picture of a component I've pulled from one another dead board to show want I want to use.

The other pictures do show resistors from boards with clear corrosion, I'm working with corroded boards which needs repairing.

Try to understand this...I'm experienced enough to know if and why I want Replace and repair corroded area of a board. My soldering is great...no I'm not going to damage anything pulling corrode components off.

Honestly I think telling people to leave corroded 27 year old components Alone is AWFUL advice.

A perfectly undamaged wirewound resistor, with minor corrosion to the leads, just requires the leads cleaning - unless the leads have corroded away massively (and are much thinner) they should be perfectly OK - often just a gentle scrape to remove the copper oxide is all that's required. But obviously it should be considered on a case by case basis - the different one in post #6 looks fairly decent.

Again, the resistors in your original picture look to be fine.

The question I was asking is what type of resistors they are?

As we've endlessly explained, they are wirewound resistors - depending which ones you're referring to? - certainly the original picture was wirewound resistors.

As someone who's repaired many thousands of items over decades, we always replaced any resistors of that type which had failed (after usually repairing what had caused then to fail) with conventional wire ended wirewound resistors of a suitable wattage, spaced off the board. This was simply both because we had no source to purchase such resistors, and they would only be applicable to a particular unit - conventional wire ended ones could be fitted anywhere.

 

[Doomguy42]

Yeah I totally agree. In my original post I said I want to replace them like for like or modern versions of the old resistor. I dont understand why that has ruffled feathers?

I made the post because I want to use as close to the originals as I can.

The reason I have made the post is because I want to use new uncorroded versions of the same resistor. In my experience working on battery damaged and corroded boards I'm not leaving ANY corrosion at all... so many components end up falling to pieces, I've all ready said there is corrosion underneath the resistors too. I have to attend to that anyway. If i'm taking the time to repair a board trace by trace I'm not going to ignore corrosion anywhere.

I don't get the logic of you guys saying you must replace your old corroded components with the same old corroded components? Where in do they teach that? What is the point in cleaning up 30-40 27 year old resistors when I can just replace with new versions of the originals? What makes the best job?

 

[Nigel Goodwin]

Yeah I totally agree. In my original post I said I want to replace them like for like or modern versions of the old resistor. I dont understand why that has ruffled feathers?

I made the post because I want to use as close to the originals as I can.

The reason I have made the post is because I want to use new uncorroded versions of the same resistor. In my experience working on battery damaged and corroded boards I'm not leaving ANY corrosion at all... so many components end up falling to pieces, I've all ready said there is corrosion underneath the resistors too. I have to attend to that anyway. If i'm taking the time to repair a board trace by trace I'm not going to ignore corrosion anywhere.

I don't get the logic of you guys saying you must replace your old corroded components with the same old corroded components? Where in do they teach that? What is the point in cleaning up 30-40 27 year old resistors when I can just replace with new versions of the originals? What makes the best job?

Either - if the components are damaged, fair enough - but in your original photo there appeared to be no meaningful damage to the resistors whatsoever?, if the resistors are substantially damaged, then replace them. Those resistors don't actually have 'wires' so are far less susceptible to corrosion damage from leaky batteries.