Help needed for unknown SEMELAB Power Zeners "8136 8215E"

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Photo? 8136 and 8215 look suspiciously like datecodes to me...

Photos probably don't provide the desired information here. The outline is not essentially different as shown in the mentioned URL


Furthermore, it is because of the baked-in thermal grease (silicon ointment) not possible to read the type numbers and modell series on the images (except the logo of manufacturer).

Nevertheless I will make images next time of those parts.

The reason for the overheating and thermal overload were unscrewed screws on the heatsink.
All zeners have zero resp. 0 Ω passage in both directions.
 
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happy now???

They are written in cyrillic on the body, I should know I have loads of them - all kinds of values which I used directly in the ground return of a transformer HT CT, to give a stable bias line.
The seller has made a mistake with alphabet with the "2" instead of cyrillic D.

zener-diode-15v-8w-d815e-russian.jpg
 

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I count 4 pcs "8136" and 3 pcs "8149" (maybe 4x 36V and 3x 49V - at whole 291VAC for the anode voltage, but I am unsure).
When an armor plant was shut down, these Zeners from SEMELAB in military version was save.
The builder of the tube preamplifier worked here at those days.
From where I can ask for datasheets ?
The ownership of the company SEMELAB have changed in the meantime.
 
I guess, nobody can help. Even not concerning a appropriate replacement in an outline for non isolated heatsink mounting like TO-220 ISO as to find under
2SA1837 - 2SC4793 Transistor PNP npn 230V 1A TO-220ISO Toshiba (8 Stuck) | eBay.
I have found replacement (TO-3 TO-220) but only for isolated mounting on heatsink - have a look to the attached pictures.
Best solution is creating a new serial voltage regulator with high voltage - high power transistor (maybe BU/BUX series) with usual zeners.
 

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I guess, nobody can help. Even not concerning a appropriate replacement in an outline for non isolated heatsink mounting like TO-220 ISO as to find under
2SA1837 - 2SC4793 Transistor PNP npn 230V 1A TO-220ISO Toshiba (8 Stuck) | eBay.
I have found replacement (TO-3 TO-220) but only for isolated mounting on heatsink - have a look to the attached pictures.
Best solution is creating a new serial voltage regulator with high voltage - high power transistor (maybe BU/BUX series) with usual zeners.
Under
A New High-Voltage Regulator
I have found the attached circuit. Instead TIP50 I want to use an ISO-outline like that one:
https://www.st.com/resource/en/datasheet/buv48a.pdf
or
BUT18AF datasheet
But what replacement are there for MJE350 in such ISO outline ?
 

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I count 4 pcs "8136" and 3 pcs "8149" (maybe 4x 36V and 3x 49V - at whole 291VAC for the anode voltage, but I am unsure).
When an armor plant was shut down, these Zeners from SEMELAB in military version was save.
The builder of the tube preamplifier worked here at those days.
From where I can ask for datasheets ?
The ownership of the company SEMELAB have changed in the meantime.
Now I have found a good replacement: 5 pcs BZY91 C56 (280V) only intended for isolated mounting on heatsink unfortunately.
 

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To watch the temperature I made this as a temporary solution according the attached images (the solution in previous post was suited only for 25mA).
Without the connected pre-amp the output voltage is 285VDC and idle current through five 56V power zeners is 330mA. And with connected pre-amp (which draws 100-110mA) 230mA (outüut voltage same value).
Because the heat transfer resistance between the sub-heat sink and the main heat sink there is a temperature gradient of 10 degrees, i. e. the zeners heat up 10 degrees above the main heat sink (approximately 60-65 degrees resp. 60-65 °C, i. e. 40-45°C above ambient temperature).

Therefore I want to have heat sinks like those from post #4 under
Sub Heatsink for 6 Zener Diodes in DO5 Outline for electric isolated Mounting

Thanks for calling an ordering address.
 

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