1N5787 4-Layer Diode equivalent circuit (M&A TVP-X)

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Hi

After years of searching the 1N5787 I give up - even brokers that listed this part sneaked out finally. I hope somebody can help me with an equivalent circuit diagram. It's used in the PSU of a Michaelson & Austin TVP-X (no schematics unfortunately) and is slowing down the B+ rise time, by switching between 13 to 15V. Datasheet attached. I want to keep this unit as original as possible, so just change or substitute this defective part. And just in case somebody has some of these .... .

Thanks
Walter

 

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Uh - is a solution to easy or to difficult ? I dont know much about solid state - some 4-layers are still availiable, but as far as I can see only in a much higher switching range (like 36V).

 

[JohnRoberts]

4 layer thyristors can be mimicked with multiple 3 layer devices.

From looking at that schemo I don't see the obvious turn on mechanism. I have seen diacs used in series with the gates of triacs or scrs to delay turn on.

If they stopped making them that suggests people stopped using them... there may be alternate ways to skin that cat.

JR

 

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Hi John
Thanks - yes the solution must be somewhere there - actualy the 4-layer diode is switching a power transistor that opens and closes B+ cap loading. Always raising the previous level tension by a step. I think I have a (questionable) hand written schemo of this part of the PSU somewhere - I'll search for it.
Thanks again - Walter