Help 2SC2530 / 2SA1080 Fujitsu Ring Emitter Transistor replacement

[Conehead]

G'day all,
I'm facing a dilemma repairing my Audiolabor Preamp!
One of the RET's went up in smoke but the type appears obsolete!
Its a Fujitsu 2SC2530 that I would require to get the thing back working.
THe transistor seems to be sitting in the line regulation for the power rails...
Any Ideas??

 

[stocktrader200]

from what I can see , 2SC2530 is a 40v NPN 0.5A transistor
If it is not in the audio path, but voltage regulation throw in a TIP31 or MJE182 and you should be fine.

 

[Mooly]

A circuit would be useful.
If it's a series pass device, did it fail or was it pushed ? If it's allowed excess voltage onto the rails has it caused other damage ?

 

[east electronics]

yeap ...a schematic will help better ...if its a voltage regulator obviously you have million ways arround it if its a current source it might not be so easy ....

while you are looking for a schematic i will drop a few phone calls to the local supply shops ...you never know what i may come up with

 

[jacco vermeulen]

www.audiolabor.de/images/stories/audiolabor/brillant-preamp-service.pdf

 

[tiefbassuebertr]

2SC2530 datasheet and Application Note, Data Sheet, Circuit, PDF, Pinout | Datasheet Archive
2SA1080 Datasheet pdf - SILICON PNP RING EMITTER TRANSISTOR(RET) - Fujitsu Microelectronics

Toshiba's 2SC2238 / 2SA968 must actually be a good replacement, also Onsemi's MJE15028/MJE15029 or MJE15030/MJE15031

Check out also this threads:
http://www.diyaudio.com/forums/soli...ver-stages-high-power-amplifier-overview.html
http://www.diyaudio.com/forums/soli...0-bd159-gbp-transit-frequency-ft-unknown.html
http://www.diyaudio.com/forums/soli...istor-families-audio-power-output-stages.html

 

[Conehead]

This site impresses me again. What a speedy reply, more than you ever could expect from a professional Customer service! Thanks for helping out and thanks to Jacco for finding those Schematics, great Job Event though they are from a different Model Audiolabor "brilliant" (I have got the "Rein") the Regulator circuit design seems to be the same. The schematics for the "Rein" on Audiolabors website are hand sketched and incomplete, missing those regulation circuits ( a shunt type in my opinion ). I have cropped the section out of the .pdf and attached here! My Preamp uses different values on the resistors and a different OpAmp (TL071 instead the drawn) Also input V in my case is 15VDC/ Output 12.5VDC. Hope this shines some more Light on it...

 

[Conehead]

To Mooly:
Can't say precisely what caused the damage! Both a short on the output or excess Rail voltage may have caused the transistor to fail. Either way, no fault in the input/ output does exist at this stage. A while ago the power supply (external) fell of the shelf and caused a loud 50hz hum. I repaired it, new rectifier and caps and the amp would work for a while until now! The "Rein" never had a great external Power supply, something on my "to do" list to build an improved one...

 

[sawreyrw]

This is a terrible circuit. You basically have 4 voltage sources in series; the 2 regulators plus the 2 amplifiers. If the sum of the voltages is not 0, the current will be huge. It will be limited by the one of the regulators, but could destroy the transistors.

 

[Conehead]

Nothing I can change about sawrey. This is how it has been designed by the manufacturer! The circuit has lasted some 24 years or so until today

 

[Mooly]

Looks like pretty much anything should work in that, stocktrader mentioned a TIP31, anything like that should do. Might be worth swapping the opamp... they can fail very very rarely... but don't fit anything other than the original type as others may latch up or do something unpredicatable.

Check those 15 ohms too.
If it fell off a shelf, perhaps there is a hairline crack somewhere on the PCB etc. Components themselves won't be damaged by the shock as such, unless the weight of a part pulls at it somehow... you know what I mean

 

[Conehead]

Thanks Mooly, you have been spot on with that Resistor! Those 15 Ohms were infinite when I tested it! Replaced that one and put a TIP 31 in there. All good as gold now
Need to replace that power supply at one stage, the heat from the transformer has got to the parts and enclosure! All old and brittle with fixed V- regulators 7815/ 7915...
Definately can do better

Cheers

 

[Mooly]

Excellent news, well done.

 

[as_audio]

It came to post 7 until the op let us knew which Audiolabor preamp model it was.

And no, the fault can not happen with output short, because this is a parallel regulator.
No, it can neither be excess input voltage, because this is limited and regulated to 15 volts.

I suspect the transistor never failed. But if - use any suitable replacement.

Post 9 is wrong, this is a primitive shunt with integrated pre-regulator and it is dual for symmetric output.

Why reply after 8.5 years ? This preamp model was sold in quantities and this thread is the first hit on
GGl if you search for "SA1080 2SC2530".

 

[jacco vermeulen]

This preamp model was sold in quantities.

A preamplifier with completely separate cases for input/output sections was very original in 1986.

Reinhard Wachowiak can be proud of his Rein/Schnell combo.
There are still plenty in active service today. Often in quite good cosmetic condition, due to the tubular aluminum case construction of about half a centimeter thickness.

 

[as_audio]

This was the last Brinkmann development for Audiolabor.