# Identify a zener diode

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#### patm58

##### New Member
Hello
I am in the USA attempting to replace a zener diode on a ECM (auto computer).
It is glass red with a silver stripe other than the black end. The numbers are perpendicular and are 62B2 (could possibly be 6282) it is cracked in half and burned. I am guessing that it is a 6.2V .5W to 1W & not sure about the B2 or 82.
Can anyone ID this thing it is tiny most of the stuff around it is .5 or 1 watt except a couple of larger resistors that are 2W.
Thanks

PS not really sure how this forum works

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#### patm58

##### New Member
pFofit-Looks like you found it for me!

Thanks
I do believe it is it. Will find out in a few days. The entire box is made by Hitachi and most of the parts that are labeled or have a logo are Hitachi. I must admit I was about to attempt to mickey mouse a 6.2 v low ohm zener with a 1K pot to see if it would work. Since the alternative was to "Scrap" the truck. Then I found a ?junk yard? selling the box "AS IS" for $150. In any case I do believe this is it, I was surprised to see that it is a 50ohm. Prior to removing and finishing the "Break" it sort of was working with bidirectional 1250 or 1350ohms. Ran like Sh$T but did run until I finished breaking the diode in half.

THANKS

#### patm58

##### New Member
Well almost the part #

Upon further looking the part on that data sheet is a square surface mount and my part is a through the holes round type.
I believe the part is a 1N5262B - has an ohm reading that makes a lot more sense 1100. It was cracked and reading 1250 or 1350 and running but very badly. The Zvoltage is a bit surprising, 51v.

Your info (pFofit) was close and led me to it.
Thanks again

#### pfofit

##### Active Member
I believe the part is a 1N5262B - The Zvoltage is a bit surprising, 51v.
1N5262b is indeed a 51 volt zener and probably not correct unless it's used as a clamp for spikes. In which case, if it was shorted you could remove it from the circuit temporary without any performance issues. Normally they use in modules a TVS-transient voltage suppressor to eat the spikes or a ZNR Transient/Surge Absorbers,this last one clamps at 22v and it is placed across the 12 volt inputs. They sometimes get toasted when somebody tries to jump start backwards

All Data schematics will not show you anything about what's inside a module.
They are like wiring diagrams and not schematics.

What is the make and model of your truck and can is this burnt device be trace back to individual input pins or is it within the circuitry of the module?

Also an image of the module and one of where the "zener" is located within would be very helpfull?

#### patm58

##### New Member
Wiring diagram only?

Below is a copy of the email the "SALES PERSON" sent. The professional product is multiple or unlimited schematics I think. As opposed to Ala carte.
PS what is the "Send trackback to " below?

Hello,
Thank you for your interest in ALLDATA. To answer your question, ALLDATAdiy does supply wiring schematics and pinouts for the ECM. Our professional product runs on average $150-$180 per month. ALLDATAdiy.com is only $26.95 per year for the initial vehicle, and$16.95 per year for each thereafter, you will have access to all the diagrams, repair information, and detailed technical service bulletins/Recalls for your vehicle. After your 4th vehicle we can issue you a power user discount for \$11.95 per year for each additional vehicle. If you would like more information on the Professional product I can forward your email to another representative. If you would like the Power User discount code please email me back.

Click on the 'Select your Vehicle' button in the middle of the page to proceed.

Thanks, and if you have any other questions, please feel free to email me back.

Matt Grima
9412 Big Horn Blvd.
Elk Grove, CA 95758
916-684-5200

#### patm58

##### New Member
600watts? 1st one

Guess I am confused. The first link in the for the spike clamping says it is a 600watt diode that is way more than the original of 1/2 a watt and the second came back as "Part not found".
patm58 aka confused

#### pfofit

##### Active Member
Their wording can be misinterputed, It says wiring schematics and ecm pinouts. I had a professional membership at alldata and apart from the internals of an alternator, I've never seen schematics for the guts of any module. The odd time they may show a Mosfet, relay or pull up/down resistor output but nothing as to what's driving these outputs. Automotive schematics are designed for mechanics and not electronic peoples. Most modules internals are propriety, secret squirrel, black boxes

Guess I am confused. The first link in the for the spike clamping says it is a 600watt diode that is way more than the original of 1/2 a watt and the second came back as "Part not found".
patm58 aka confused
You need to read the entire datasheet. It is not a diode, it is a TVS or specialized zener diode. The 600 Watts is peak power @ 1 millisecond. Since a TVS works quickly and does nothing until required, as when a spike comes along, a continuous spec. parameter would be meaningless. Second link worked for me.
Also, as stated, I was just using those links as examples as to what is sometimes employed. I never said that they were replacements for what you have as we have yet to determine where your "zener" is located within the circuit and what it is doing.

You need to find a good magnifier and determine the numbers on your dud part and as I susgested previously, try to determine where the part is in the circuitry by following the foil traces. If it doesn't go directly to a pinout then it is most likey a regular zener of which you need to determine its valve and hope that nothing else in the circuit was destroyed along with it.

cheers

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#### patm58

##### New Member
No good ECM ECU schematic at alldata

Thanks for saving me the money. If no one can get them, How do the "ECM ECU after market re builders" repair and sell modules?

Just to satisfy my curiosity, If you have a "Pro Membership" could you at least look to see if they have any vehicle ECM or ECU schematic(s), (of course, within your no extra cost area of your membership boundaries). Assuming you have the time and willingness to do so. I would surely & greatly appreciate it.

#### patm58

##### New Member
About the image of the board

I attempted to scan the board and got a good image of the foil side but not the top side. Tried my didgital camera phone and scanner neither gives a good enough pic to identify the individual parts. The foil side is good and have made two notes on it where the two parts are located that "Burned out".

Not quit sure how to get you the image though.

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#### pfofit

##### Active Member
Thanks for saving me the money. If no one can get them, How do the "ECM ECU after market re builders" repair and sell modules?
Cause like any authorize shops they receive the proprietary info.

Just to satisfy my curiosity, If you have a "Pro Membership" could you at least look to see if they have any vehicle ECM or ECU schematic(s), (of course, within your no extra cost area of your membership boundaries). Assuming you have the time and willingness to do so. I would surely & greatly appreciate it.
Why did I know this was coming

As stated above Year, make, model, and engine?

#### pfofit

##### Active Member
Not quit sure how to get you the image though.

#### patm58

##### New Member
1989 Isuzu Pickup spacecab 2.6L 4cyl ECU# FED 12V 8943342531

1989 Isuzu Pickup space cab 2.6L 4cyl I-TEC Module ECU# FED 12V 8943342531
second, third & 4th box as follows:
EPC-K112 (3rd box empty) 9310

#### patm58

##### New Member
ECU Board scan

Did my email go away? I think I erased it.
Here is the scan of the board.