Igniter electronic part identify

[Guest]

I cannot identify the two diodes that connect accross the two Darlington Pair D977 collector and base, cathode to collector. It is a small black diode only marked 350.
I am guessing that it could be a Zener or a Transient Voltage Suppression Diode or just a standard diode.
I am busy buzzing out the GS1000 igniter PCB so that I can keep some parts if it does fail one day.
Any help is much appreciated.

[Thomas Kenny]

What is a Zener or Transient Voltage Suppression Diode, ??? Man your way ahead of me on this stuff.. :-) Tom

[Steve]

What is a Zener or Transient Voltage Suppression Diode, ??? Man your way ahead of me on this stuff.. :-) Tom

This is one of those times when "if you have to ask, you just won't understand".

All these parts are just specially-shaped containers for smoke. Don't do anything to let the smoke out and they should last quite a while.

Good luck, Matchless.

.

[Thomas Kenny]

Wow now I understand, thanks for enlightening me. :-)

[GQROD]

I cannot identify the two diodes that connect accross the two Darlington Pair D977 collector and base, cathode to collector. It is a small black diode only marked 350.
I am guessing that it could be a Zener or a Transient Voltage Suppression Diode or just a standard diode.
I am busy buzzing out the GS1000 igniter PCB so that I can keep some parts if it does fail one day.
Any help is much appreciated.

If electronic components are made to conform to code standards then a test of the component will tell if you if is a diode.

As to which type may require researching through college electrical engineering books which may have a photo and description of the part. Any college professor can help you find the right book.

If these parts are proprietary then part numbers may not help, so it will be a matter of reverse engineering it by building the bread board and testing each components function with a meter.

Hope this helps.

[Matchless]

If electronic components are made to conform to code standards then a test of the component will tell if you if is a diode.

As to which type may require researching through college electrical engineering books which may have a photo and description of the part. Any college professor can help you find the right book.

If these parts are proprietary then part numbers may not help, so it will be a matter of reverse engineering it by building the bread board and testing each components function with a meter.

Hope this helps.

I am sure all the electronic components are standard off the shelf and not custom. They are 28 years old and use Japanese standard coding, so it is also an issue of what was available 28 years ago and what the specs were and then the hunt for an equivalent.
So far I am sure I have identified all the other components and have also drawn up the schematic.
I am hoping someone who is a boffin in electronic R & D would see this and be able to advise.

A new unit cost about $400 and can easily be repaired for under $20, even built for under $100 I think.

[Thomas Kenny]

If you can post a picture of it, I will show it to my neighbor who builds radios and still uses his morse code key. He might be able to identify the part. Tom

[Matchless]

If you can post a picture of it, I will show it to my neighbor who builds radios and still uses his morse code key. He might be able to identify the part. Tom

I will get a picture up later today. Yes radio hams who build their own radios are guys who know how to find equivalent parts. Thanks for the offer.

[errorcauser]

I worked in electronics' repair for years. No way can you tell what type a diode it is just by looking. Maybe get a magnifying glass and see if you can find any numbers or anything printed on the diode if you're lucky. If it were me, I'd look high and low for schematics of similar circuits and see what parts they use in those. If the circuits you find in schematics are pretty close to what we have in our igniters, then the diode's will be very close as to their function and type. I guess, search Google for ignition circuit schematics. Maybe search for circuits using the 2SD977 or a substitute transistor. If the diode is across the legs of the 2SD977 I would think it's just a regular type diode, not a zener. From what I can remember, and it's been years for me, and my memory is not that good anymore, a zener diode will have one end tied to ground, being used to keep voltage at a certain level within the circuit.

I saw a schematic of and electronic ignition online somewhere, but I never saved it. All I was needing at the time was the 2SD977. I replaced my 2SD977 with a pair of TIP120's from radio shack. I'm not sure they'll hold up because the specs are not exactly the same as the 2SD977. But, so far, they're working just fine. Time will tell I guess. At $1.59 cents each, I figured I'd roll the dice.

EDIT:

After rereading what you wrote, I see your diode is from collector to base. Most regular type diodes would be across the base and emitter. I found this..

http://www.electronicsteacher.com/circuits-and-diagrams/automotive-car-and-motorcycle-schematics/electronic-car-ignition-circuit.php

Maybe it'll help you some ? After doing a little investigating, I realize how rusty i am, and how much i've forgot...err.. or how bad my memory has gotten...lol

[Matchless]

Thanks for that reply. I have come to similar conclusions as the only usefull schematic I have found shows 180 V Zeners, two in series, but to ground, so confirming your thought that those in the igniter are unlikely to be be zeners as they are not taken to ground.
There are numbers on them "350" and nothing else and I cannot find any clues as to what the 350 means or stands for. In those days it usually would point to a 1N350 in the Japanese configuration.
Hopefully someone who has looked at this before also sees this thread.
Thanks again.

[Suzuki mad]

And whats it got to do with a GS or a GSX made by Suzuki?

Suzuki mad

[Jaguarjoe]

If someone had a curve tracer that would identify that part. Are there any electronic repair shops in your area?

If that 2SD977 is the transistor that drives the coils then that diode is prolly a zener diode meant to protect the 2SD977 from the hugh inductive kick back you'll get from the coil primary. A regular diode won't work because it will slow the circuit down too much.

[errorcauser]

If someone had a curve tracer that would identify that part. Are there any electronic repair shops in your area?

If that 2SD977 is the transistor that drives the coils then that diode is prolly a zener diode meant to protect the 2SD977 from the hugh inductive kick back you'll get from the coil primary. A regular diode won't work because it will slow the circuit down too much.

Although I'm totally rusty when it comes to this, but what you just said makes perfect sense when I look at the diagram on the site that I found.
The zener diode would act as a shunt, and shunt the voltage to ground through the 100Ohm resistor R10 to protect the transistor I'd imagine.

[Matchless]

I noticed that is another zener in another part of the circuit clearly marked 6.8 and thus 6.8V but I have never seen a small zener marked 350, to me saying 350V and only know that they can go up to 200 V.
This diode is also not connected to ground directly or via a resistor. That made me think it may be a Transient Voltage Suppression Diode with a 350 V spec?? used in place of an ordinary Zener. (P6KE400 is one I could find)

If I can get the clarity on this part, I can share the schematic of the igniter on the forum which may be of use for repairing a failed one. I think I have all the details now except this. I will also put together a testing procedure for the igniter and the ignition system.

[Matchless]

As promised here is a picture of the diodes and the part of the schematic where they are shown as D4 & D5. Not sure if this will help.