What does it mean by "leaky"?

[kuer]

If somebody says these output transistors got leaky, does it mean something like liquid coming out of the transistor? or any other meanings?

Actually I checked my transistors, it looks perfect physically.

I need some advice.

Thank you very much.

 

[DPH]

Can you give a more clear example of what you're asking?

The closest thing I can get to your question is gate leakage on a MOSFET.

 

[Michael Bean]

I believe you're referring to the propensity of early semiconductors, particularly germanium, to pass some current when they're not supposed to, it has nothing to do with physically leaking fluid or anything else. Modern semis don't have this issue.

Mike

 

[rayma]

If somebody says these output transistors got leaky, does it mean something like liquid coming out of the transistor?

That refers to current, not fluid. When p-n junctions are reverse biased and should be off, they have a certain small "leakage current"
that can drastically increase with damage, or improper operation.

 

[kuer]

Can you give a more clear example of what you're asking?

The closest thing I can get to your question is gate leakage on a MOSFET.

Thank you for your quick reply.

My marantz receiver 2235b works, but only for 20mins from cold start, it is overheated on the heatsink. If I don't close the cover, seems working with no issue.

Found that one of output transistors is very hot. now I am buying new transistors, not received.

Actually I measured all transistors, should be good according to the testing method.

Checked online, somebody says the transistor is "leaky", don't undersand this word at all.

 

[kuer]

That refers to current, not fluid. When p-n junctions are reverse biased and should be off, they have a certain small "leakage current"
that can drastically increase with damage, or improper operation.

Yes, thanks. another issue is that when turning on or off, there is a pop sound on one speaker, guss the same cause. First step, I will replace transistors.

 

[DPH]

Kuer--I think the other two posters are going to get you along the right direction. Sounds like there's a bias problem (which would mean that the output transistors are conducting beyond what they normally should, i.e. leaky)

 

[kuer]

Kuer--I think the other two posters are going to get you along the right direction. Sounds like there's a bias problem (which would mean that the output transistors are conducting beyond what they normally should, i.e. leaky)

The problem is that the bias cant be adjusted much, very high voltage, forget it. No way to adjust correctly.

 

[kuer]

I believe you're referring to the propensity of early semiconductors, particularly germanium, to pass some current when they're not supposed to, it has nothing to do with physically leaking fluid or anything else. Modern semis don't have this issue.

Mike

Ok, thanks, understand this. thanks.

 

[Enzo]

There is the measure of the normal leakage current as described above by others. But a transistor can also fail in a way that allows current to flow when it should not, and we refer to that as a leaky transistor.

 

[AndrewT]

reverse current increases massively as the transistor gets hotter.

 

[Nigel Goodwin]

The problem is that the bias cant be adjusted much, very high voltage, forget it. No way to adjust correctly.

There's got to be some way that the bias is set, even if it's not readily adjustable - do you have a schematic you could post?.

However, from your list of problems it looks pretty obvious that there's a fault in the amplifier - which in a DC coupled amp could be pretty well anywhere.