Figuring our a replacement transistor.

[Xdevo1973]

I am trying to replace a driver transistor in a small amp. One channel went out. I switched the driver transistor from the other channel and it came back. The print looks like FR52. Here are the readings from the good one. Can someone recommend one with similar readings?

 

[MFRD]

Can you take a good legible pic of the transistors face?

 

[redk9258]

What is it in?

 

[ivandezande]

You didn’t really give us any info! Model number? Picture of transistor?

 

[Xdevo1973]

Can you take a good legible pic of the transistors face?

 

[Nashou66]

View attachment 3831334

Not close enough to read, also if this lettering is not eligible maybe the other channels is.

Also what are you fixing? That is the units model number and brand.

Athanasios

 

[Xdevo1973]

It is in this- a 1970s stereo made in the UK with a 10 watts maximum per channel amp. A very obscure brand. Elizabethan LZ212View attachment 3831412

 

[gslikker]

Funny, this disc/radio/aux selector is a combination of two switches. Same is on my Sugden A21 mk3

Maybe you can use a BC327-25, observe maybe pinout to be different.

 

[Xdevo1973]

Well Google solved it. I typed the values into the search bar and their AI robot told me a 2N3906 would be a very good match. I ordered 10 on EBay for and darn Google was right. The numbers were very close. Both channels are working well and the stereo sounds good. Now to change those 1000 microfarad caps.

 

[MFRD]

So, AI recommended a replacement for an unknown transistor...?

 

[gslikker]

So, AI recommended a replacement for an unknown transistor...?

Just for fun, I just tried google AI and typed "unknown pnp transistor best replacement" and indeed it comes back with 2N3906 for TO-92.

So, just forget all your electronics knowledge, buy a humanoid robot and let it repair all your stuff.

 

[Nashou66]

Its a BFR52 from texas instruments

BFR52 TEXAS INSTRUMENTS TRANSISTOR X1PC - Langrex

BFR52 TEXAS INSTRUMENTS TRANSISTOR NEW AND UNUSED 1 PIECE

www.langrex.co.uk

https://www.silicon-ark.co.uk/datasheets/bft85-datasheet-texas-instruments.pdf

Athanasios

 

[Goldie99]

Its a BFR52 from texas instruments

It does seem a little strange... the BFR52 should be an NPN, while the OP is showing the supposedly good one as a PNP ?

 

[Nashou66]

It does seem a little strange... the BFR52 should be an NPN, while the OP is showing the supposedly good one as a PNP ?

Hmm yeah weird, is it possible there is a circuit that could use either an NPN or a PNP? I am not an EE so Just wondering.

EDIT, did a search and I guess this can be a possibility

Auto-Biasing Circuits: These use heavy negative feedback and a split power supply (+/- voltages). If an NPN is inserted, it utilizes the positive rail; if a PNP is inserted, it utilizes the negative rail.

Athanasios

 

[Xdevo1973]

It is not a BFR52. I ordered those and they didn’t work. Whatever it was, it was a PNP transistor.