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FS: 2SJ50 and 2SK135 HITACHI power mosfets

Hi again A'af

Would more than likely be interested in more than 2 pairs depending on price and your ability to convince me these are definitely genuine Hitachi NOS parts.

Show us some good photo's, and if possible some documentation to support these are genuine.

We do not want another dual JFet saga.

Best Regards

Gary..
 
A'af said:


A'af,

It is really nice of you to again offer these group buy facilities after being burned the first time by a dishonest guy.

But I would urge you to be very carefull, you don't want to go through that again I guess.
I have looked at your pictures, and noticed that they are labeled with the '2S' prefix. However, in my experience, originals are *never* labeled like '2SK135' but always like 'K135'. So, while I obviously cannot look into your devices, I would be very, very carefull.

Why not deliver a few to some people here who would want them anyway and let them check them out before committing again several 1000 $'s to this?

Jan Didden
 

Bobken

Member
2002-12-23 11:22 pm
UK
janneman said:


I have looked at your pictures, and noticed that they are labeled with the '2S' prefix. However, in my experience, originals are *never* labeled like '2SK135' but always like 'K135'. So, while I obviously cannot look into your devices, I would be very, very carefull.

Jan Didden

Hi,

Although I can understand Jan's cautionary comments, my practical experiences differ from his (once again). ;)

I used a lot of these Hitachi mosfets years ago, but I haven't purchased any for probably 30yrs., when I found that Toshiba mosfets performed better in the same circuits. I don't believe that anyone was into counterfeiting back in those days, and I have just checked some of my 'old' stock.

Some have the Hitachi 'Logo' in the middle at the top, and some just have "Hitachi" written on them, instead.

Some have "K135" (those with the logo), and some have "2SK135" (those with Hitachi written on them).

Interestingly, all of them have " Japan" written on the same line as the date code, and I notice that not all of these in A'af's pics show this. As my remaining mosfets are quite early devices, it may be that the makers dropped the "Japan" notation in later production, though.

Regards,
 
Bobken said:


Hi,

Although I can understand Jan's cautionary comments, my practical experiences differ from his (once again). ;)

I used a lot of these Hitachi mosfets years ago, but I haven't purchased any for probably 30yrs., when I found that Toshiba mosfets performed better in the same circuits. I don't believe that anyone was into counterfeiting back in those days, and I have just checked some of my 'old' stock.

Some have the Hitachi 'Logo' in the middle at the top, and some just have "Hitachi" written on them, instead.

Some have "K135" (those with the logo), and some have "2SK135" (those with Hitachi written on them).

Interestingly, all of them have " Japan" written on the same line as the date code, and I notice that not all of these in A'af's pics show this. As my remaining mosfets are quite early devices, it may be that the makers dropped the "Japan" notation in later production, though.

Regards,



Hmm. Yes, maybe. I also noticed that those '2SK' and '2SJ' devices show exactly the same date code. Isn't that unusual?

Anyway, I'm not looking for these devices, but in the Netherlands we have a saying "a warned man counts for two".

Jan Didden
 
hi~~~

in the foto 2 in line 2, there is 2 pieces of 2SK135 without 2SK ;) and also have japan printing on those 2 others not :D

I also have of this mosfet without prefix.. bobken, can you put your foto here (not yours! the mosfet i meant... :D ) for comparison ;)

I already tested all, and the result is okay..

seems i must tested them in working circuit for sure, but really i'm not have time to do this for now

but this power mosfet is very sensitive to destroy if anything wrong happen in the circuit...:bawling:

As ussual will give you 1 to 1 replacement or full refund without hassles if its not genuine or else, thanks.

all the best,
a'af
 

Bobken

Member
2002-12-23 11:22 pm
UK
Hi A'af,

Much as I would like to help with a picture, I have no means for doing this, unfortunately. And I don't think you would be very impressed with an old man's photo, anyway!;)

In any case, I don't see how this would help much and I only mentioned the appearance of the mosfets I have in stock to indicate that if the lettering includes the prefix "2SK", or whatever, this is just *not* a reliable indication of whether these are genuine or not. Jan had earlier suggested that this was so, but Hitachi have obviously marked these devices differently at certain times.

From my point of view, there is nothing which would cause me particular concern over the appearance of these mosfets, but only testing them properly will tell anyone for certain. Like Jan, I think it would be very unfortunate if they turned out to be fakes, from yours and the purchasers' standpoints, but appearance is not what matters here. Maybe the date codes are unusual in being similar, but if both types came from the same source, they could possibly have been made at the same time, but that would be the only concern I might have if I was purchasing these devices.

I have 2 differently-marked types, as previously mentioned, and I noticed that some pics you showed do have the "Japan" wording which is on all of my devices. As I also mentioned, I don't know what significance this is anyway, as all of these very early devices came from Japan in the first place, and it may be that later versions dropped the "Japan" marking because of this. Few (if any?) other devices I have ever seen actually show the country of origin on the front of the component, so this would not be unusual.

As you say, these mosfets are very prone to static damage and HF oscillation which can be destructive, so care must be taken when testing or handling them.

I can only suggest that potential purchasers should initially accept your word for the authenticity of these devices, especially as you have given your assurance that you will refund anyone who discovers that there is a problem with them.

I don't think that there is much sensible alternative for anyone seriously seeking these long-obsolete parts, and as I recently confirmed on the J-Fet thread, I have received my refund from A'af for the dual J-Fet devices which I had previously returned, and so I wouldn't have any hesitation in ordering from A'af again. These Hitachi devices are not easy to come by, and I don't see what there is to lose, except for the nuisance of needing to return them in the (hopefully unlikely) event of them being fakes.

It just happens that I don't personally use these mosfets nowadays, and I have sufficient 'spares' in stock for any likely replacements etc., so like Jan, I don't have the need for any more.
 

finwbu

Member
Paid Member
2002-12-08 10:31 am
Helsinki
Power Mosfet from HITACHI original one !!
 

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