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T912 F782


Mitchel Rought
 

I recently went to use my T912 scope and no trace, found a component defective, it is labeled as F782, 1.5A 125V fast blo but has resistor color codes, not sure if it's a pico fuse or fusable resistor
it is located on the low voltage power supply board along with F742 and F743 all three look identical
these parts are not listed in the parts manual
Tectronix was no help at all, any help would be greatly appreciated
thank you

Mitchel Rought
644 Main Street
Chemung,New York 14825
607-742-5426
mjrought@...
@binford


Michael W. Lynch
 

Mitchel,

I have a "parts only" T922 I will look on that board and see if I can identify the location and identity of those fuses. I do not see any of those fuses on the schematic that I am looking at.

--
Michael Lynch
Dardanelle, AR


Mitchel Rought
 

Michael
these fuses are not on my prints or parts list either
F782 is in the circuit for the flood gun heaters using U784 and is in front of CR783 located on the low voltage power supply board
thanks


tekscopegroup@...
 

Not sure if I might be wrong, and I am not at all familiar with the T912, but did you mean that you see a small (like 1/4W) resistor and a spring inside a regular glass fuse? (like in a 3AG, etc). If so I have seen these before, and the resistor I assume is part of the fuse to help it open quicker by generating heat that helps to melt the bond so the spring will retract the fuse link and open the circuit. If so, I would just replace the fuse with regular fast blow of the same specs that you indicated earlier (125V 1.5A). Not sure these fuses with the resistor and spring inside are still being manufactured. Anyway just an idea.


Michael W. Lynch
 

Mitchel,

I did not think about this when I spoke earlier. I have a T922 (non-storage) so it is likely very different inside. I will take a look and see if there are any such fuses inside the T922.

--
Michael Lynch
Dardanelle, AR


Mitchel Rought
 

I believe it is a pico fuse, it's approx. the size of a 1/4 resistor with four bands, red,green,red,red and the last band is twice the width of the other bands
I'm not used to pico fuses being rated this way, used to them listed by amp rating
the bands equal 1500 which might mean 1500Ma. or 1.5A?
I put a picture in the photo album if you want to look at it
thanks


tekscopegroup@...
 

On Fri, Oct 2, 2020 at 08:16 AM, Mitchel Rought wrote:
I put a picture in the photo album if you want to look at it
thanks
Can you please post a link to the album?


Glydeck
 

T912 F782 — picture of unlisted fuse - 1 photos · Updated Oct 2

https://groups.io/g/TekScopes/photo/254490/0?p=Created,,,20,2,0,0

On Oct 3, 2020, at 8:37 AM, tekscopegroup@... wrote:

On Fri, Oct 2, 2020 at 08:16 AM, Mitchel Rought wrote:
I put a picture in the photo album if you want to look at it
thanks
Can you please post a link to the album?