old fisher 1266XB need help

[piero]

I need help for my old fisher 1266XB (year 1994); after a coil replacement and 1hr of good work the component No.Q508 (4 pins) labelled as:
IRFD
S41 RF3
9210
broken, compromising also a red component labelled as:
WIMA
0,1
63-N
E3


I do not find the broken component on the schematics and the electronic components retailer doesn't understand what it is; in the next post I will attach a photo;

someone knows the specifications/characteristics of the two components or an indication for an equivalent one?

may be there is a relation with the new coil however it is specified as “suitable for X series mod. 1225, 1270, 1236 e 1266”?

thankyou for your time and cooperation
regards
Piero

[Qiaozhi]

I need help for my old fisher 1266XB (year 1994); after a coil replacement and 1hr of good work the component No.Q508 (4 pins) labelled as:
IRFD
S41 RF3
9210
broken, compromising also a red component labelled as:
WIMA
0,1
63-N
E3


I do not find the broken component on the schematics and the electronic components retailer doesn't understand what it is; in the next post I will attach a photo;

someone knows the specifications/characteristics of the two components or an indication for an equivalent one?

may be there is a relation with the new coil however it is specified as “suitable for X series mod. 1225, 1270, 1236 e 1266”?

thankyou for your time and cooperation
regards
Piero

After your first post you can add attachments. The Wima component is a capacitor (100nF), but we will probably need to see a photo in order to identify the other one.

[piero]

thanks for the answer; I've attached a photo composition of the components;

regards
Piero

[ivconic]

It's IRFD9210, fet.
http://www.irf.com/product-info/data...rfd9210pbf.pdf
Nothing special with that component. You can obtain it at local supplier, i suppose...

[piero]

thankyou;
have you any idea of the reason of failure? may be related with the coil - even if I'm quite sure in regard to the compatibility - or is a "physiological" behaviour considering the age of the device?

Piero

[ivconic]

thankyou;
have you any idea of the reason of failure? may be related with the coil - even if I'm quite sure in regard to the compatibility - or is a "physiological" behaviour considering the age of the device?

Piero

Good question. Not sure.
I am not having exact 1266 schematic.
All what i have is 1265 schematic which is very simillar to 1266 but not the same.
Such fet can be used in power supply stage.
In that case than failure happens because of something wrong related to battery.
Have you changed something around battery?
Also such fet can be used in TX too, similar as at CZ5 detector.
In that case failure is most probably related to coil, cable or something at TX.
First check and be sure about fet's role there. At what stage it is?
I can't tell for sure because i am not having schematic.

[ivconic]

Most probably is fet used in power supply stage.
Than must be something wrong with battery there? Connections? Overvoltage?
Pay attetnion on those two resistors, maybe they are "touching" each other and form occasional "short" there?
Estrange them to prevent touching.

[piero]

thanks ivconic; I've just found a schematic on this site in a 2010 message:

http://www.sendspace.com/file/poce13
Fisher 1266-X Schematic 10-5-1993 (Rev. I) 300dpi scan

but I'm not able to interpret it...
I didn't touch anything on batteries or connections but I'll verify whether it happened accidentally along my internal cleaning after the coil replacement;
good idea also the short between the resistors; I'm going to verify this evening

regards
Piero

[ivconic]

I have to disappoint you; it is schematic of old 1266 version, not the one you have there.
Seems you are having one of the latest 1266 revision...

[ivconic]

Damn i am getting blind!

Yes that schematic will do just fine!
And i had it already but i never really analyzed it up to now!

Yes it is fet used in power supply stage.
In case you haven't previously changed nothing there; than must be about those touching resistors!
If you previously opened it and by accident moved one resistor towards another; than it is very possible that you made a occasional "short" between them....
Along with fet; do check and change those tantalums also!
Cheers!

[piero]

you were right ivconic: I verified a short between resistors.....
I called 9 big retailers close to Milan: nobody has a IRFD9210; on alltransistors.com seems that there is an equivalent in IRFD9220, this found in two specimens
Result (Equivalent transistors)


Polarity
Struct
Pd
Uds
Udg
Ugs
Id
Tj
Fr
Cd
Rds
Mnf
Caps
1.
IRFD9210
P-Channel
MOSFET
1.3W
200V

10V
0.4A
150°C


3
IRF
HEXDIP
2.
IRFD9220
P-Channel
MOSFET
1.3W
200V

10V
0.56A
150°C


1.5
IRF
HEXDIP


can I try with the equivalent one or is an highly hazardous venture?

thanks again
Piero

[piero]

sorry, table is unreadable

[ivconic]

....

can I try with the equivalent one or is an highly hazardous venture?

thanks again
Piero

Yes you can, no problem.
Just to remind you: check and replace tantalum capacitor too.
Cheers!

[ivconic]

Before you switch it ON and check detector:
we must be sure about those resistors, as i see those are R502 and R503.
If those made "short" and caused fet to burn; THAN we must know for sure which sides of those resistors actually made "short"?
Because there is a chance that Q602 burned also (not likely; but worth to be checked).
That depends on which side of R502 resistor touched which side of R503.
So before you switch it on; make sure that Q602 is ok.
As i see it; most probably 30k (R503) resistor is shorted and that caused fet to burn.
Cheers!

[piero]

just to inform you that, after a long test period, repairing works
thanks again ivconic

piero