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Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

Surface mount diode identification



 
 
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  #1  
Old August 29th 09, 07:53 PM posted to sci.electronics.repair
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Posts: 257
Default Surface mount diode identification

I have an alarm board with two shorted surface mount diodes. These are
about the size of a quarter watt carbon resistor only just a slight
bit fatter. They are marked: MX6AA and MX50AA. Can anyone please
identify these for me? Thanks, Lenny.
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  #2  
Old August 30th 09, 08:28 AM posted to sci.electronics.repair
external usenet poster
 
Posts: 420
Default Surface mount diode identification

On Sat, 29 Aug 2009 11:53:54 -0700 (PDT), "
wrote:

:I have an alarm board with two shorted surface mount diodes. These are
:about the size of a quarter watt carbon resistor only just a slight
:bit fatter. They are marked: MX6AA and MX50AA. Can anyone please
:identify these for me? Thanks, Lenny.


Are they glass MELF style or moulded plastic similar to either of these photos?
http://img.alibaba.com/photo/1078070...001_LL4007.jpg
http://product-image.tradeindia.com/...SMD-Diodes.jpg

My first guess would be 1W zeners so perhaps you can check to see if they have
6V and 50V ratings respectively (assuming they are not dead).
  #3  
Old August 31st 09, 01:18 PM posted to sci.electronics.repair
external usenet poster
 
Posts: 40
Default Surface mount diode identification

On Aug 30, 3:28*am, Ross Herbert wrote:
On Sat, 29 Aug 2009 11:53:54 -0700 (PDT), "

wrote:

:I have an alarm board with two shorted surface mount diodes. These are
:about the size of a quarter watt carbon resistor only just a slight
:bit fatter. They are marked: MX6AA and MX50AA. Can anyone please
:identify these for me? Thanks, Lenny.

Are they glass MELF style or moulded plastic similar to either of these photos?http://img.alibaba.com/photo/1078070...SMD-Diodes.jpg

My first guess would be 1W zeners so perhaps you can check to see if they have
6V and 50V ratings respectively (assuming they are not dead).

They are not round more like flat and they are definitly shorted.
Lenny
  #4  
Old September 2nd 09, 10:19 AM posted to sci.electronics.repair
external usenet poster
 
Posts: 420
Default Surface mount diode identification

On Mon, 31 Aug 2009 05:18:42 -0700 (PDT), wrote:

:On Aug 30, 3:28*am, Ross Herbert wrote:
: On Sat, 29 Aug 2009 11:53:54 -0700 (PDT), "
:
: wrote:
:
: :I have an alarm board with two shorted surface mount diodes. These are
: :about the size of a quarter watt carbon resistor only just a slight
: :bit fatter. They are marked: MX6AA and MX50AA. Can anyone please
: :identify these for me? Thanks, Lenny.
:
: Are they glass MELF style or moulded plastic similar to either of these
photos?
http://img.alibaba.com/photo/1078070...SMD-Diodes.jpg
:
: My first guess would be 1W zeners so perhaps you can check to see if they
have
: 6V and 50V ratings respectively (assuming they are not dead).
:They are not round more like flat and they are definitly shorted.
:Lenny

'Fraid you are stuffed then.. Other than figuring out the function by tracing
out the circuit around those devices and then making some intelligent
deductions...

No manufacturer ident (on the board or the system) you can approach?
  #5  
Old September 3rd 09, 07:21 AM posted to sci.electronics.repair
external usenet poster
 
Posts: 40
Default Surface mount diode identification

On Sep 2, 5:19*am, Ross Herbert wrote:
On Mon, 31 Aug 2009 05:18:42 -0700 (PDT), wrote:

:On Aug 30, 3:28*am, Ross Herbert wrote:
: On Sat, 29 Aug 2009 11:53:54 -0700 (PDT), "
:: wrote:

:
: :I have an alarm board with two shorted surface mount diodes. These are
: :about the size of a quarter watt carbon resistor only just a slight
: :bit fatter. They are marked: MX6AA and MX50AA. Can anyone please
: :identify these for me? Thanks, Lenny.
:
: Are they glass MELF style or moulded plastic similar to either of these
photos?http://img.alibaba.com/photo/1078070...LL4007.jpghttp...
:
: My first guess would be 1W zeners so perhaps you can check to see if they
have
: 6V and 50V ratings respectively (assuming they are not dead).
:They are not round more like flat and they are definitly shorted.
:Lenny

'Fraid you are stuffed then.. Other than figuring out the function by tracing
out the circuit around those devices and then making some intelligent
deductions...

No manufacturer ident (on the board or the system) you can approach?


The board is a fire alarm main board and is manufactured by GE
Security probably off shore. These diodes could be anyones I guess.
The thing is, this exact failure, that is these two diodes shorting
out has happened many times before on this security installation. It
usually occurrs after a bad lightning storm. For the time being GE has
repaired these units under warranty but the warranty period is coming
to an end. These boards are no longer in production so it also
involves sending the board out for repair and so the premises are not
protected during that period. I would have to guess that at least one
of these diodes is accross the input reversed biased to ground because
when it shorts out the unit displays "Ground fault" and the zone is
knocked out of commission. Would you think that this is probably a
zener or perhaps just a standard run of the mill diode? Lenny
  #6  
Old September 3rd 09, 03:20 PM posted to sci.electronics.repair
external usenet poster
 
Posts: 12,207
Default Surface mount diode identification


wrote:

The board is a fire alarm main board and is manufactured by GE
Security probably off shore. These diodes could be anyones I guess.
The thing is, this exact failure, that is these two diodes shorting
out has happened many times before on this security installation. It
usually occurrs after a bad lightning storm. For the time being GE has
repaired these units under warranty but the warranty period is coming
to an end. These boards are no longer in production so it also
involves sending the board out for repair and so the premises are not
protected during that period. I would have to guess that at least one
of these diodes is accross the input reversed biased to ground because
when it shorts out the unit displays "Ground fault" and the zone is
knocked out of commission. Would you think that this is probably a
zener or perhaps just a standard run of the mill diode? Lenny



Lenny, you should check the liability of repairing fire alarm
hardware without the OEM's blessings. You may end up assuming all
liability if something goes wrong. If the laws haven't been changed,
any repair other than replacing a failed board with anything other than
a factory built or repaired assembly makes you liable for future
losses. When I investigated this years ago I was told that I needed the
original OEM service data, and a minimum of 10 million dollars in
liability insurance. I'm sure it has gone up, over the years.


--
You can't have a sense of humor, if you have no sense!
  #7  
Old September 4th 09, 07:28 AM posted to sci.electronics.repair
external usenet poster
 
Posts: 40
Default Surface mount diode identification

On Sep 3, 10:20*am, "Michael A. Terrell"
wrote:
wrote:

The board is a fire alarm main board and is manufactured by GE
Security probably off shore. These diodes could be anyones I guess.
The thing is, this exact failure, that is these two diodes shorting
out has happened many times before on this security installation. It
usually occurrs after a bad lightning storm. For the time being GE has
repaired these units under warranty but the warranty period is coming
to an end. These boards are no longer in production so it also
involves sending the board out for repair and so the premises are not
protected during that period. I would have to guess that at least one
of these diodes is accross the input reversed biased to ground because
when it shorts out the unit displays "Ground fault" and the zone is
knocked out of commission. Would you think that this is probably a
zener *or perhaps just a standard run of the mill diode? Lenny


* *Lenny, you should check the liability of repairing fire alarm
hardware without the OEM's blessings. *You may end up assuming all
liability if something goes wrong. *If the laws haven't been changed,
any repair other than replacing a failed board with anything other than
a factory built or repaired assembly makes you liable for future
losses. *When I investigated this years ago I was told that I needed the
original OEM service data, and a minimum of 10 million dollars in
liability insurance. *I'm sure it has gone up, over the years.

--
You can't have a sense of humor, if you have no sense!


I know it seems theres always a lawyer where ever you look these
days.Lenny
  #8  
Old September 4th 09, 09:00 AM posted to sci.electronics.repair
external usenet poster
 
Posts: 1,569
Default Surface mount diode identification

On Wed, 2 Sep 2009 23:21:30 -0700 (PDT),
put finger to keyboard and composed:

On Sep 2, 5:19*am, Ross Herbert wrote:
On Mon, 31 Aug 2009 05:18:42 -0700 (PDT), wrote:

:On Aug 30, 3:28*am, Ross Herbert wrote:
: On Sat, 29 Aug 2009 11:53:54 -0700 (PDT), "
:: wrote:

:
: :I have an alarm board with two shorted surface mount diodes. These are
: :about the size of a quarter watt carbon resistor only just a slight
: :bit fatter. They are marked: MX6AA and MX50AA. Can anyone please
: :identify these for me? Thanks, Lenny.
:
: Are they glass MELF style or moulded plastic similar to either of these
photos?
http://img.alibaba.com/photo/1078070...LL4007.jpghttp...
:
: My first guess would be 1W zeners so perhaps you can check to see if they
have
: 6V and 50V ratings respectively (assuming they are not dead).
:They are not round more like flat and they are definitly shorted.
:Lenny

'Fraid you are stuffed then.. Other than figuring out the function by tracing
out the circuit around those devices and then making some intelligent
deductions...

No manufacturer ident (on the board or the system) you can approach?


The board is a fire alarm main board and is manufactured by GE
Security probably off shore. These diodes could be anyones I guess.
The thing is, this exact failure, that is these two diodes shorting
out has happened many times before on this security installation. It
usually occurrs after a bad lightning storm. For the time being GE has
repaired these units under warranty but the warranty period is coming
to an end. These boards are no longer in production so it also
involves sending the board out for repair and so the premises are not
protected during that period. I would have to guess that at least one
of these diodes is accross the input reversed biased to ground because
when it shorts out the unit displays "Ground fault" and the zone is
knocked out of commission. Would you think that this is probably a
zener or perhaps just a standard run of the mill diode? Lenny


Could they be transient voltage suppression (TVS) diodes? Transorbs?
Mosorbs?

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.
  #9  
Old September 7th 09, 03:38 AM posted to sci.electronics.repair
external usenet poster
 
Posts: 420
Default Surface mount diode identification

On Wed, 2 Sep 2009 23:21:30 -0700 (PDT), wrote:

:On Sep 2, 5:19*am, Ross Herbert wrote:
: On Mon, 31 Aug 2009 05:18:42 -0700 (PDT), wrote:
:
: :On Aug 30, 3:28*am, Ross Herbert wrote:
: : On Sat, 29 Aug 2009 11:53:54 -0700 (PDT), "
: :: wrote:
:
: :
: : :I have an alarm board with two shorted surface mount diodes. These are
: : :about the size of a quarter watt carbon resistor only just a slight
: : :bit fatter. They are marked: MX6AA and MX50AA. Can anyone please
: : :identify these for me? Thanks, Lenny.
: :
: : Are they glass MELF style or moulded plastic similar to either of these
:
photos?
http://img.alibaba.com/photo/1078070...LL4007.jpghttp...
: :
: : My first guess would be 1W zeners so perhaps you can check to see if they
: have
: : 6V and 50V ratings respectively (assuming they are not dead).
: :They are not round more like flat and they are definitly shorted.
: :Lenny
:
: 'Fraid you are stuffed then.. Other than figuring out the function by tracing
: out the circuit around those devices and then making some intelligent
: deductions...
:
: No manufacturer ident (on the board or the system) you can approach?
:
:The board is a fire alarm main board and is manufactured by GE
:Security probably off shore. These diodes could be anyones I guess.
:The thing is, this exact failure, that is these two diodes shorting
ut has happened many times before on this security installation. It
:usually occurrs after a bad lightning storm. For the time being GE has
:repaired these units under warranty but the warranty period is coming
:to an end. These boards are no longer in production so it also
:involves sending the board out for repair and so the premises are not
rotected during that period. I would have to guess that at least one
f these diodes is accross the input reversed biased to ground because
:when it shorts out the unit displays "Ground fault" and the zone is
:knocked out of commission. Would you think that this is probably a
:zener or perhaps just a standard run of the mill diode? Lenny

I doubt it is a standard diode. More like a zener or transorb.
Did you try the GESecurity website? I notice that if you have a login and
password you can get access to the reference manual for some of their FA
systems, eg. Fireworx;
http://www.gesecurity.com/portal/sit...true&seriesID=
  #10  
Old September 12th 09, 01:01 PM posted to sci.electronics.repair
external usenet poster
 
Posts: 40
Default Surface mount diode identification

On Sep 6, 10:38*pm, Ross Herbert wrote:
On Wed, 2 Sep 2009 23:21:30 -0700 (PDT), wrote:

:On Sep 2, 5:19*am, Ross Herbert wrote:
: On Mon, 31 Aug 2009 05:18:42 -0700 (PDT), wrote:
:
: :On Aug 30, 3:28*am, Ross Herbert wrote:
: : On Sat, 29 Aug 2009 11:53:54 -0700 (PDT), ": :: wrote:

:
: :
: : :I have an alarm board with two shorted surface mount diodes. These are
: : :about the size of a quarter watt carbon resistor only just a slight
: : :bit fatter. They are marked: MX6AA and MX50AA. Can anyone please
: : :identify these for me? Thanks, Lenny.
: :
: : Are they glass MELF style or moulded plastic similar to either of these
:
photos?http://img.alibaba.com/photo/1078070...LL4007.jpghttp...
: :
: : My first guess would be 1W zeners so perhaps you can check to see if they
: have
: : 6V and 50V ratings respectively (assuming they are not dead).
: :They are not round more like flat and they are definitly shorted.
: :Lenny
:
: 'Fraid you are stuffed then.. Other than figuring out the function by tracing
: out the circuit around those devices and then making some intelligent
: deductions...
:
: No manufacturer ident (on the board or the system) you can approach?
:
:The board is a fire alarm main board and is manufactured by GE
:Security probably off shore. These diodes could be anyones I guess.
:The thing is, this exact failure, that is these two diodes shorting
ut has happened many times before on this security installation. It
:usually occurrs after a bad lightning storm. For the time being GE has
:repaired these units under warranty but the warranty period is coming
:to an end. These boards are no longer in production so it also
:involves sending the board out for repair and so the premises are not
rotected during that period. I would have to guess that at least one
f these diodes is accross the input reversed biased to ground because
:when it shorts out the unit displays "Ground fault" and the zone is
:knocked out of commission. Would you think that this is probably a
:zener *or perhaps just a standard run of the mill diode? Lenny

I doubt it is a standard diode. More like a zener or transorb.
Did you try the GESecurity website? I notice that if you have a login and
password you can get access to the reference manual for some of their FA
systems, eg. Fireworx;http://www.gesecurity.com/portal/sit...em.f76d98ccce4...


I talked to the area rep. No they won't tell me anything. "company
secrets" or some other bull****. The only thing to do is have them
repair the board and then remove the new parts and try to put them on
a curve tracer perhaps. Lenny.
 




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