TDK 517 component - can anyone identify picture

[pnb]

Hi all,

I have a burnt component with small blob of metal in my uncles Fluke (the AC circuit is dead).

Opening it up there is this obvious burnt component with a marking TDK 517 down near the input terminals.

Google turns up nothing. Can anyone tell me what it is and what component I can use to replace it?
The circuit on this board is very fine, so I suspect high voltage, not high current.

Board marking is RT1.

[cheapie]

Re: TDK 517 component - can anyone identify picture

All I can tell is that it appears to be a thermistor of some sort made by TDK or EPCOS. It's most likely a PTC for protection.

[pnb]

Re: TDK 517 component - can anyone identify picture

I cant find any Fluke parts that look like this. I cannot find any Fluke schematics/circuit diagrams. I cant find any reference to a TDK 517 on the web.

Seems hard to believe but it look like this is irreparable short of taking it back to Fluke for an outrageously expensive board replacement.

PS Fluke model is an 865, similar to 863 or 867b

PS - found a service manual for models 863/867b and this suggests it could be a:
Thermistor: POS, 1.1K, +-20% 25c

Going to try that. Cant get any worse than it is.

Thanks, all.

[ben7]

Re: TDK 517 component - can anyone identify picture

Is there any text on the other side of the component?

It might be an NTC from the Epcos (TDK) B57164K series, though, there is no mention of a 1.1K value.

[Calchaqui]

Re: TDK 517 component - can anyone identify picture

I dont think that it's a fundamental component, something else must be wrong.

[ben7]

Re: TDK 517 component - can anyone identify picture

Do you have a schematic for the meter?

[retiredcaps]

Re: TDK 517 component - can anyone identify picture

PS - found a service manual for models 863/867b and this suggests it could be a:
Thermistor: POS, 1.1K, +-20% 25c

It is definitely a PTC (not NTC). It, obviously, should read about 1.1K ohms if it is working.

As a simple test, you can replace it with a 1K ohm resistor and see if the AC function works. If it does, then you can go about getting the correct part.

The only one that I found that was 1.1K, but only goes up to 500V was

http://ca.mouser.com/Circuit-Protect...mistor&FS=True

[redwire]

Re: TDK 517 component - can anyone identify picture

Hey I notice that part also used in the Fluke 10-12, 863, 867 series multimeters, and the original part number is listed in the 10 service manual:
Fluke p/n 867192; TDK p/n 911P67E112MW07

It always has power resistors in series with it, I would check those too. It's a safety-related part.

[cyberhack]

Re: TDK 517 component - can anyone identify picture



page 47

[pnb]

Re: TDK 517 component - can anyone identify picture

Uodate.

Didnt have a service manual but found a manual for a fluke similar looking/numbered fluke (867 instead of 865) (865 has a board numbered 867 in it) and that circuit point was identified as a :

Thermistor, POS,1.1k, 20% 25c.

Got one from local electronics shop and it looked nothing like that part (much slimmer, different colour [colour probably - wrong voltage? ) soldered it in and.... no change, so yes, not a fundamental part causing the problem even though it is burnt.

Looks to me like the parts that were supposed to provide protection: fuse, thermistor, did not.
I guess it is probably one of the many IC's so it will have to stay as it is.
Not worth the cost of an official service/board replacement.

[retiredcaps]

Re: TDK 517 component - can anyone identify picture

Got one from local electronics shop and it looked nothing like that part (much slimmer, different colour [colour probably - wrong voltage? ) soldered it in and.... no change, so yes, not a fundamental part causing the problem even though it is burnt.

Questions.

Does the new part measure 1.1K ohms?

Does DCV and ohms measure/work properly?

Not worth the cost of an official service/board replacement.

If you have no interest in fixing it, I would be happy to take this broken meter off your hands. PM me.

[pnb]

Re: TDK 517 component - can anyone identify picture

yes, it did measure around 1.1k ohm and all other functions worked.
However the meter doesn't belong to me, it belongs to my uncle and I was just trying to fix it up for him. He still uses it for the other functions.

[modemhead]

Re: TDK 517 component - can anyone identify picture

The red rectangular component looks like it could be the AC coupling capacitor. I am unfamiliar with 86x meters, but often this cap is designated "C1" in many Fluke meters. The photo is a little fuzzy, but it also looks like there could have been an arc from an over-voltage event between the thermistor and the cap. The cap could be damaged which would affect all AC functions.

Take it out and test it if you have the means. You can TEMPORARILY tack in a 0.01uF to 0.1uF capacitor you may have laying about and try measuring a low-voltage AC source, like a small 12Vac power transformer or a signal generator. If that restores the AC functions, then remove the temporary cap and order a proper replacement. This part is usually rated for 1000V.

[pnb]

Re: TDK 517 component - can anyone identify picture

Thanks I did de-solder that safety cap and it tested according to spec. Pretty sure the problem is way down the line closer to logic IC's so I put it all back together and gave it back to the owner.

[Calchaqui]

Re: TDK 517 component - can anyone identify picture

Thanks I did de-solder that safety cap and it tested according to spec. Pretty sure the problem is way down the line closer to logic IC's so I put it all back together and gave it back to the owner.

did u earn some money?

[pnb]

Re: TDK 517 component - can anyone identify picture

Didnt do it for any remuneration. Family.

[glicos]

Re: TDK 517 component - can anyone identify picture

What is the symptom of your uncle's fluke dmm? The component you mention is PTC and YES that's for input protection of your meter.

[pnb]

Re: TDK 517 component - can anyone identify picture

That circuit - AC (only) is non-operational. Blank screen. It looks like the component(s) that were supposed to provide AC input protection, did not.
This project is not going to be revisited.

[glicos]

Re: TDK 517 component - can anyone identify picture

Ok pnb. I'm very much interested in revisiting the project. A partial glimpse on the schematic of 867B (same board used on 865) suggest there's more problem other than RT1 on the AC input circuitry that prevents the ASIC from starting normally in AC mode. RV1-RV3 (varistors) should be checked also. 80% chances that the ASIC (RIC2) is ok since other function of the GMM is working normally, only the AC mode side is acting strange.

Additionally, try also to clean the contacts of the rotary switch and ensure proper contacts. I encountered this problem on my GMM 867B (No display on when switching on component test, Resistance test just a blank screen)...

Hope when you have time you can revisit it again...

[ashim]

Re: TDK 517 component - can anyone identify picture

it is NTC or PTC