My Transistors, original or copy?

[jacco vermeulen]

Originally Posted by zinsula

Pins bent in a way which doesn't agree with the datasheet.

Tino-baby,

not one Toshiba datasheet mentions bent-leg options, but sure can be ordered, plenty examples, try K107, K246, K363, K366.
Gender bender leads likely means late production runs.

[zinsula]

Originally Posted by jacco vermeulen

Tino-baby....

Yep, sometimes I would like to get back some (in this case, some means quite a lot, unfortunately) years.

Originally Posted by jacco vermeulen

....Gender bender leads likely means late production runs.

Gender bender, ......hehe.

Thanks anyway for the information, it is very useful.

[unclexray]

DIYers, beware of DIY gene. I bought a pair of 805T tubes from him, one was bad. he told me to return it. return ship was $52. Sent it priority USPS he said he never received the faulty tube. He won't return emails to resolve issue.

[KatieandDad]

I've just bought a batch of 2SK170BLs from www.dalbani.co.uk

They have proved to be fakes.

[viktor1986]

Originally Posted by KatieandDad

I've just bought a batch of 2SK170BLs from www.dalbani.co.uk

They have proved to be fakes.

Why do you think that they are fakes? Have you measured them? And?

[unclejed613]

Originally Posted by pattox

Some time ago I (see post 405) I asked for opinions about whether my Toshiba sc5200s were genuine. The answer seemed to be that they were. More recently I had a bad amplifier driver transistor failure which I am trying to troubleshoot. One possible cause was bad power transistors )the sc5200's I had asked about.

I have split open 2 of them after the failure and to me the internals do look genuine. But I'm hoping someone with more expertise can give me their opinion.

big die, looks about right. what is that about 5 or 6mm? that's what it should be, and as your picture shows, no goo on top of the die.

[pattox]

Originally Posted by unclejed613

big die, looks about right. what is that about 5 or 6mm? that's what it should be, and as your picture shows, no goo on top of the die.

Thank you for the reassurance unclejed613. I also came to the conclusion that they were ok. I had split open some other similar power transistors which I knew to be genuine and when I compared them to the sc5200s they all looked much the same.

In the future, if I am in any doubt at all about the pedigree of power transistors, then I will buy one or two extra ones, split one open and look inside.

I think sacrificing one device is the most practical way to check. It is cheap insurance because a power transistor which fails and creates an output short circuit can have dreadful consequences to both the amp and speakers.

[unclejed613]

the professional parts analysis companies use xray machines. i wish i had access to one

[pdul]

That might be a good idea for a new diy project

[KatieandDad]

Originally Posted by viktor1986

Why do you think that they are fakes? Have you measured them? And?

DEFINITELY FAKES. Idss measures at 2mA for the badged 2SK170BL.

Idss should be between 6 and 12mA. Even the devices look re-badged. Look at the wiping marks on the face of the devices.

Dalbani were very quick to replace them.

Funny how the whole batch were low Idss whereas a previous order were well within spec.