Output Transistor Question

[Joe bags]

Hi guys

I have a HK ACTOR AT115 Sub A.

It's a powered sub woofer. I have found a faulty output transistor.
It uses MJ11015/6

Can I replace these with MJ15003/4?

Cheers

[diydidi]

I'm sure it will be fine. i have done this in the past. Still going strong. just rebias the amp after just be sure.

[J M Fahey]

Yes, as far as its real, not fake.

Buy from a reputed supplier.

In general, Techs stock MJ15024/25 as "universal replacements" which cost one buck more and use them everywhere a strong NPN or PNP is needed.

Check that the emitter ballast resistors are fine, the driver transistors health (might be dead), and that other transistors aren't open.

Use a lamp bulb limiter the first time you turn amp on , also disconnect the speaker and any load, until you are certain everything is right, it's easy to miss some small bad part so play it safe.

[Jazz P Bass]

Yeah but, the MJ11015/6 transistors are 'darlington' type, are they not?

[J M Fahey]

Yeah but, the MJ11015/6 transistors are 'darlington' type, are they not?

GOOD EYE !!!!!
You're ABSOLUTELY right?

I read the post very fast and read MJ15015/16 , while in fact it's MJ11015/16 .

Now I remember H&K use them in a couple amps.

Yes they are Darlingtons and yes they are somewhat hard to find and somewhat expensive ... but still available AFAIK .

EDIT: just checked, Mouser has them at some U$5 each

Good catch JPB

[Enzo]

So now the question arises, does the OP really need MJ11015 or did he mean to type MJ15015?

[J M Fahey]

If I remember well, he needs the Darlingtons.

It's a German amp, they don't do things like everybody else.

Very good: 120V, 200W, 30A transistors by the way; and TO3 metallic

So they can not be replaced by TIP142/147

[Joe bags]

Thanks for the replies.

Yes the transistors in the amp are MJ11015/6 Darlingtons.

So I would have to replace with originals?


Initially I was referencing Roy Tellasons Parts page which has a pretty comprehensive transistor characteristic list.

Link below.

He has the MJ11015/6 and the MJ15003/4 as Darlingtons.
But the datasheets don't say anything about MJ15003/4 being Darlingtons.

Hence the question!!








Roy J. Tellason's Parts Pages

[Joe bags]

Another quick question

Can I replace MJ11015 with MJ11015G?

The G's are much cheaper on Farnell.
Voltage is -120 rather than +120.

[DrGonz78]

I would be willing to bet that those negative voltages on their web page is a typo. I mean how could you have -30 amps or why would they put it that way?
MJ11015G - ON SEMICONDUCTOR - TRANSISTOR, PNP, -120V TO-3 | Farnell element14

http://www.mouser.ee/ProductDetail/O...2b3GPMMg%3D%3D

Seems to me to be the same transistor, but I am not sure what the G indicates. Click on the data sheet on that web page and it is the same as MJ11015.

[Joe bags]

Yea I've seen the negative voltages before and always wondered what the deal was with them.
Apparently the G stands for PB free package. Lead free I think

Some Lead trivia!

"Solving the Plumbum (Pb) conundrum

Used in ancient times, lead (or 'Plumbum', Pb, in Latin) is a metal with a long application history. In fact, the word 'plumber' is derived from the Roman use of lead pipes for carrying water. However, when absorbed by the human body, lead is a cumulative poison detrimentally affecting health in several ways. And in children, lead can impede brain development, making them particularly vulnerable to lead poisoning."

[J M Fahey]

"G" means "Green" , a twisted way to refer to Lead Free
And of course they are the current production ones, the non "G" would be the NOS ones ... no need to go for them.
And the "-30A' label is fine, it means 30A coming from the negative supply.
Another way to insist they are PNP transistors.

[Enzo]

The data sheets do not say anything about Mj15003 being Darlington because they are not Darlington.

[g1]

Initially I was referencing Roy Tellasons Parts page which has a pretty comprehensive transistor characteristic list.

Link below.

He has the MJ11015/6 and the MJ15003/4 as Darlingtons.

That's a typo. The MJ15003/4 are not Darlington as has been mentioned. I've notified him of the error.

[Enzo]

I never rely on web-site convenience listings, I much prefer the actual data sheet for a part. Most part listings in Mouser have a link for the data sheet, whether you order from them or not.

G for green means less characters in the part number field than PBF.