This came up on another forum and I found it interesting because there seems to be no consensus on what this "FTR" means with resistors. I may have known this in the past (haha) but it is now forgotten.

The question is, what does FTR mean when it shows a resistor in a parts list like "FTR 1.8k".
Other entries are such as "carbon 1.2k" and "metal film 3.9k" or similar, yet these are just "FTR" followed by a value.

There are a lot of guesses but nobody seems to know for sure.
Any ideas?

 

Hello,

A search gives different results:
http://www.ftrqg.com/en/product/338.html
And a bit down on this page:
https://www.ralec.com/en-global/resistance/index/fully_lead_free_halogen_free?page=2

Bertus

 

Hello,

A search gives different results:
http://www.ftrqg.com/en/product/338.html
And a bit down on this page:
https://www.ralec.com/en-global/resistance/index/fully_lead_free_halogen_free?page=2

Bertus

Hi,

Thanks, but what bothered me about assuming the manufacturer was FTR was because of the parts listing which would look like this:
carbon 1.8k (1/3 watt)
metal film 2.9k (1/3 watt)
FTR 4.7k (1/3 watt)

and those FTR resistors are all under 100 Ohms I think.

The also list come capacitors:
TF 0.22uF

don't know what TF means either.

 

It might help getting better guesses if there was some idea of what the circuit is and what role these resistors play in it. Or how old the schematic is (i.e., roughly when the circuit was designed).

My best guess, if it has to be a type of resistor, would be something like "fixed thick-film resistor".

TF might indicate a thin film, but it might also indicate a tantalum. Again, any information on how the capacitor is used in the circuit can improve the guess quality. Is it polarized? Is it surface mount? Is it used as a decoupling capacitor?

 

hi Al.
Check this out.
E

 

hi Al.
Check this out.
E

Hi Eric,

That's what I was thinking too, but they do not list the part as FTR1234 or something like that. They just list it as:
FTR 1.8k 1/3 watt

and also I do not see any 1/3 watt resistors on the pdf list. So I was still wondering.

This is related to the Luxman I-525 Audio Amplifier.

 

It might help getting better guesses if there was some idea of what the circuit is and what role these resistors play in it. Or how old the schematic is (i.e., roughly when the circuit was designed).

My best guess, if it has to be a type of resistor, would be something like "fixed thick-film resistor".

TF might indicate a thin film, but it might also indicate a tantalum. Again, any information on how the capacitor is used in the circuit can improve the guess quality. Is it polarized? Is it surface mount? Is it used as a decoupling capacitor?

Yes there are many guesses, I was looking for some absolute information.
The device here is the Luxman I-525 Audio Amplifier. There is a service manual in pdf format that can be downloaded with a quick search. It shows everything even the PC boards. If you can't find it let me know I'll try to find the link again.
Thanks.

 

Hello again,

I found some definite information on this.

I found another parts list from the same manufacturer, so we now have the first list and the second list.
On the first list it lists a resistor with a specific part number as "FTR" but on the second list it shows the same part number as "Rd" which they note is Carbon. They also show some resistors as "Rm" which is actually Flameproof, and "Rc" which is Cement. They also have "Rf" but they do not indicate what that stands for.

So it appears that "FTR" cannot mean Flameproof, and that the resistors on the first list with "FTR" can be of different compositions.
On the second list ones that are less than 1 Ohm seem to be all Cement, and the ones greater than 1 Ohm and less than 1k seem to be flameproof OR Carbon (one 560 Ohm resistor appears as a Carbon type and one appears as Flameproof), and the ones greater than 1k are all Carbon.

This would mean that to order a part we would have to have the actual part number in order to get the right part. All the part numbers are clearly given for each resistor, but unfortunately they all look like "in house" part numbers which means we would only be able to get the right part from them, without more information that is. This is a trick that was used a lot back in the day where you had to order the part from the company that you bought the device from. Some of the parts themselves would even be marked with the in-house part number so even if you got the part from them you still may not be able to identify it even if it was a common part like a TTL 7400 nand gate because it would be stamped with a seemingly obscure number, not "SN7400" or similar.