Searching (no luck) for T03 style replacement

[Dryjoint]

Hi all. I'm repairing an audio amp. The output devices are T03-can F15N and F15P. No other markings, date code or anything. I've searched the web with no useable results. I guess 3055's & compliments would probably do, but I'd like to do a proper job. Any takers?

Thanks, Steve.

 

[OperaHouse]

Found F14 and F16, but these are both diodes. What is the vintage of this equipment. The only real consideration is whether these are germanium and that would be easy to convert.

 

[Dryjoint]

The "vintage" is circa 1994! I'll take them out tonight to see if any are still intact and do a gain check with the DVM. They may turn out to be fet's! At the moment the +/- fuses are blowing on power up, so I reasoned that at least two (opposites) had gone short circuit. we'll see. Thanks for the reply. Steve.

 

[Comcokid]

Hummm - I was going to suggest that you try

http://www.getmanuals.com,

but, currently the address seems invalid. Anyway, a manual for the audio amp might be the first step in identifing the device.

 

[zeitghost]

It might be useful if we knew the model number & make...)

And the power output.

 

[OperaHouse]

Just a little service tip. Wire up an electrical plug with a 60-75W lamp in series, an old extension cord is quick. This will limit current to a safe level so a short or a bias problem can be diagnosed. If you don't do this, a problem with a driver may take out the new transistors.

 

[nbucska]

a commercial amplifier was designed for minimal cost --
you can afford to select more expensive,better part
so try to pick as close to ideal specs as possible.

You have to satisfy the owner and not some abstract specification -- it shouldn't be hard.



Plesae read FAQ240-1032
My WEB: <

http://geocities.com/nbucska/>

 

[ScottyUK]

There are a couple of parts listed as being from NEC which bear similar p/n's. These are 2SF15 and 2SF16. The entire 2SF series are SCRs under the Japanese numbering system. From memory, the other common Jap prefixes are:

2SA / 2SC are fast PNP & NPN BJT's respectively
2SB / 2SD are slower PNP & NPN BJT's respectively
2SJ / 2SK are P channel & N channel FETs respectively

What brand is the amp? SCRs seem a strange component for the average audio amp to be using.


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I don't suffer from insanity. I enjoy it...

 

[OperaHouse]

I would expect to see a few more markings than that on the case. It can be a little cryptic with manufacturer and date coding. Is the F in a different type? Short of any new info, form follows function. Just pick something with appropriate voltage and current for the amp.

 

[VEBill]

"...audio amp...output devices...F15N and F15P."

Maybe these are markings for matched pairs. In other words, each amplifier off the production line would have a pair with the same xx number: FxxN and FxxP. Maybe... maybe not.

 

[ScottyUK]

Yes, s similar thought was starting to occur to me too. There are a few suppliers of transistors specially for the 'audiophile' market, a group which has much more money than sense. These are just standard transistors, but selected to have good matching. Perhaps the original manufacturer's markings are over-written?

It seems the brand and model of this amplifier is still a secret.


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I don't suffer from insanity. I enjoy it...

 

[VEBill]

Matching output devices isn't too far out in Audiophile la-la Land. It's fairly common practice even for Avg Joe HiFi. I've seen it many times, even in RF amplifiers.

 

[Dryjoint]

Scotty: No secret, just been out for a few days!
It's a Musical Fidelity, "Elektra E100".
VE1BLL: I'm with you on the la-la land thingy.
In the meantime... I've found out that they are just good ole' bipolars. I've ordered some MJ15024's & 5's. I'll check them on the 'scope. If they look ropey I'll try MJ21193 & 4 (but they're over £6 each). Thanks for the comments; wee'll see how it goes. Steve.

 

[felixc]

It is one of those Audiophile amplifiers, so the transistors may very well be matched pairs. Do you know if your customer uses this amp in a real hi-fi environment? If not then he may not notice the difference in sound.

 

[Dryjoint]

Hmmm.... I won't say who, but he's a world-famous opera singer(!!) But for all that, not above asking, "Hey Steve, can you have a look at my amp? I was playing some rock & roll very loud through big speakers and it just stopped working." LOL.