Elekit TU-8200

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Elekit TU-8200 kit Zener diodes

I am assembling a TU-8200 kit which I recently purchased from TubeDepot.

The Assembly Manual supplied with the kit is not clear about the
exact part numbers of the Zener diodes at positions ZD1, ZD2, ZD3
and ZD4. The Circuit Diagram, also supplied with the kit, shows that
ZD1 and ZD2 is of type BZX79C12 but ZD3 and ZD4 is of type 1N5929B.
As far as I can tell these two parts are not compatible, one is
12.05V, 500mW and the other is 15V, 3W.

It appears that my kit contains 4 pieces of BZX7912 (the Circuit Diagram
only calls for these for positions ZD1 and ZD2) and no 1N5929B.

Anyone who has already built the kit please let me know if I can use
the supplied BZX7912 parts for ZD1, ZD2, ZD3 and ZD4, or if I would
have to get 1N5929B Zeners for position ZD3 and ZD4.
 
I am assembling a TU-8200 kit which I recently purchased from TubeDepot.

The Assembly Manual supplied with the kit is not clear about the
exact part numbers of the Zener diodes at positions ZD1, ZD2, ZD3
and ZD4. The Circuit Diagram, also supplied with the kit, shows that
ZD1 and ZD2 is of type BZX79C12 but ZD3 and ZD4 is of type 1N5929B.
As far as I can tell these two parts are not compatible, one is
12.05V, 500mW and the other is 15V, 3W.

It appears that my kit contains 4 pieces of BZX7912 (the Circuit Diagram
only calls for these for positions ZD1 and ZD2) and no 1N5929B.

Anyone who has already built the kit please let me know if I can use
the supplied BZX7912 parts for ZD1, ZD2, ZD3 and ZD4, or if I would
have to get 1N5929B Zeners for position ZD3 and ZD4.

The ZD1-Z4 are made of Glass
D1~D4 are black color
You must install according to the indication in the PCB board.

You should have 4 ZD (made of glass) and 4 black Diode.
They are packed in different plastic bags.
 
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It appears that my kit contains 4 pieces of BZX7912 (the Circuit Diagram
only calls for these for positions ZD1 and ZD2) and no 1N5929B.

Anyone who has already built the kit please let me know if I can use
the supplied BZX7912 parts for ZD1, ZD2, ZD3 and ZD4, or if I would
have to get 1N5929B Zeners for position ZD3 and ZD4.

Just saw this question.

I had noticed the same while building my own unit. I believe this is a mistake in the schematics, if you look at page 3 in the manual then you will see that there is no difference between ZD1-ZD4.

They may have considered the bigger Zener but then dropped the idea. The purpose of this components is protecting the FETs from high transient voltage between gate and source that could kill them. These transients may occur during turn-on and turn-off. A 3W Zener would certainly be an overkill here.
 
@paczeltf

Thank you for reply.

After staring at the circuit diagram for a while and getting the response from vkung on the subject I went ahead and installed the supplied Zeners.
I experienced no issues, of course.

I also upgraded the rectifiers and most of the caps as you recommended in the other related thread. I used Rubycons (MXK, BXW) for the 400 V part positions.

Best regards,
Péter
 
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