Fluke 8846A defective due to overvoltage

[mechachris]

Hello technician,

I destroyed a Fluke8846A due to incorrect measurements.
I swapped the primary and secondary side of a 24V transformer and created an overvoltage.
I had about 900 to 1200 volts at the measuring tips
I can no longer recognize the SMD imprint on component Q41 in the SOT23 housing.
Can someone tell me what is written on component Q41?
I was able to reconstruct everything else.

Greeting,
mechachris

 

[bertus]

Hello,

It seems that the 8845 and 8846 share the same manual:
http://www.jabse.com/L0ZsdWtlLzg4NDVhX3VtLnBkZg==
There are some pictures of the 8845:
http://www.jabse.com/L0ZsdWtlLzg4NDVBL3Bob3Rv
Perhaps you can see something on those pictures.

Bertus

 

[mechachris]

Thanks Bertus for the quick answer.
But unfortunately I can't see the imprint of C41 on the pictures.

 

[mechachris]

don't know the capacitor C146 either, but there's no print on it either.
I have to estimate the value

 

[bertus]

Hello,

Here I found a site with some more info:
https://xdevs.com/fix/f8846a/
There are some clickable high resolution pictures.

Bertus

 

[mechachris]

Hello Bertus,
unfortunately there is no usable picture available.
I attached a picture for the component search

 

[bertus]

Hello,

Unfortunately, the parts are not carrying any numbers on the picture of the given site:



bertus

 

[mechachris]

Yes exactly!
On the component Q39 is written PD that means BSS84LT1G = Mosfet transistor P channel.
There are also 2 letters printed on component Q41. But the photo reflected it.
You have to moisten the component and illuminate it with a lamp, then you can see the imprint.

 

[73's de Edd]

There are also 2 letters printed on component Q41. But the photo reflected it.
You have to moisten the component and illuminate it with a lamp, then you can see the imprint.

If that was being the case then, and you WERE able to make them out, why didn't you give those two alfa /numeric symbols to us ?

Looking at the foil paths, associated with that transistor pair, they seem to be interconnected, akin to Darlington or Sziklai pairing combinations of bipolar circuitry.

Also, can you determine what Mx pin is involved in receiving that sole related trace from them, that is routed down and over to the right, and then going under the Maxxim 329 octal analog multiplexer 16 pinIC . . . . . . What pin number is it being?
Thereby confirming if they are being related to an inputting from or an outputting from that MUX chip . . .with my leaning towards their receiving an MUX output.

 

[mechachris]

the Q41 burned down on my mainboard.
There is no print. That's why I don't know which component to use.
I only know that it is a SOT23 housing.

I take a photo of my circuit board and draw the connection.

LG
mechachris

 

[mechachris]

I drew the connections.
Q39 = BSS84L I got that from a picture from the Net

 

[eugahn3]

My Fluke 8846A ohm function is blown out, can some one identify these SMD ?
Symbol SMD marking
Q41 26
Q44 39W
CR45 A7W
CR67 WV
CR68 JY