I need help about a power transistor DELCO GN 7285547-337 please, thanks.

Thread Starter

chillon

Joined Dec 15, 2020
6
hi everyone i wonder if some one can give me some information WHERE TO BUY about this transistors for ge console model rc-4539 a i can't find any information and references on line may be i can use other similar but i don't know with ones
for those transistors name is delco gn 7285547-337 - ed2n thats all number i can see i hope some one can help me please thanks so much
 

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AlbertHall

Joined Jun 4, 2014
10,778
I doubt it will make much difference but that 'GN' is actually 'GM'
I remember delco transistors like that from the early seventies and they were germanium so a silicon replacement probably won;t work well.
Is the transistor definitely faulty?
 

Thread Starter

chillon

Joined Dec 15, 2020
6
I doubt it will make much difference but that 'GN' is actually 'GM'
I remember delco transistors like that from the early seventies and they were germanium so a silicon replacement probably won;t work well.
Is the transistor definitely faulty?
hi yes my error about gn yes is DELCO GM power transistor and yes i did tested several times and I tested 4 and 3 of 4 yes they are faulty . any idea or recommendation for a similar to replace?
thanks AlbertHall for your replays I appreciated
 
Last edited:

LowQCab

Joined Nov 6, 2012
135
Since you have this mounted to an odd Heat Sink,
I will assume that you are not doing an all original, numbers-matching, restoration on an ancient GM Car Radio,
so throw it away, there are gazillions of far superior Transistors, (or complete Radios), available for dirt cheap.
These Transistors haven't been produced since around ~1975, so if you happen to find one,
its gonna cost you ~$50++ Dollars, plus shipping,
and there's no guarantee that it will last very long, or even work at all .
These Transistors were used in the most crude Class-A Amplifier configuration that you could ever imagine,
and they were normally run EXTREMELY HOT at all times, which doesn't do much for their life expectancy.
They're big and fat, not necessarily for high current handling,
but because they were required to dissipate so much heat continuously.
They were used in this configuration because it was the
CHEAPEST way to make a Car Radio Amplifier back in the 60's.
They would run your Battery dead in less than ~30 minutes from the ridiculous Class-A Current,
even with the volume turned all the way down.
And yes, they were Mono, with 1- Power Transistor, and 1- Dash Speaker, placed right in the middle of the Dash.
Sometimes they would use the metal body of the Car as the Speaker Ground connection, so that
they could use just 1- wire to power the Speaker, saving the cost of 1- ground wire on millions of Cars.
Total garbage.
.
.
 

Thread Starter

chillon

Joined Dec 15, 2020
6
Since you have this mounted to an odd Heat Sink,
I will assume that you are not doing an all original, numbers-matching, restoration on an ancient GM Car Radio,
so throw it away, there are gazillions of far superior Transistors, (or complete Radios), available for dirt cheap.
These Transistors haven't been produced since around ~1975, so if you happen to find one,
its gonna cost you ~$50++ Dollars, plus shipping,
and there's no guarantee that it will last very long, or even work at all .
These Transistors were used in the most crude Class-A Amplifier configuration that you could ever imagine,
and they were normally run EXTREMELY HOT at all times, which doesn't do much for their life expectancy.
They're big and fat, not necessarily for high current handling,
but because they were required to dissipate so much heat continuously.
They were used in this configuration because it was the
CHEAPEST way to make a Car Radio Amplifier back in the 60's.
They would run your Battery dead in less than ~30 minutes from the ridiculous Class-A Current,
even with the volume turned all the way down.
And yes, they were Mono, with 1- Power Transistor, and 1- Dash Speaker, placed right in the middle of the Dash.
Sometimes they would use the metal body of the Car as the Speaker Ground connection, so that
they could use just 1- wire to power the Speaker, saving the cost of 1- ground wire on millions of Cars.
Total garbage.
.
.
that's why probably they overheat and fault. surprises me why general electric using those in home console stereo I will keeping looking for a replace one checking your recommendations
thanks LowQCab I appreciate
 

LowQCab

Joined Nov 6, 2012
135
You need to replace the entire Amplifier and Receiver guts with new modern stuff,
which you can get in kit-form on E-Bay or Ali-Express.
All of the cheapo factory Capacitors will be either shorted, or leaking from age,
and the super cheap resistors are probably noisy as hell,
with values drifting all over the place from humidity and age,
not to mention bad solder joints, corrosion, and super cheap printed circuit boards.
If it was a Tube (Valve) Amp, I'd say to restore it, but not an old Transistor Amp,
( most especially not a cheap Class-A Amp ),
they were designed to be built absolutely as dirt-cheap as humanly possible,
which makes them not worth the time, headaches, and money to restore them.
And, you really should replace the speakers at the same time,
you can get quality speakers cheap at Parts-Express.
.
.
 

RIKRIK

Joined Oct 11, 2019
127
Also normally between the GM & Number is DTS- with what it is. They haven't labeled the part for some reason.

I wonder if you put a voltmeter on the signal wire going to the transistor. You could work out the voltage of a germanium replacement.

But it depends on you cabinet. If you can replace it with new parts from a cheap kit on eBay. It will be more functional.
 

Thread Starter

chillon

Joined Dec 15, 2020
6
You need to replace the entire Amplifier and Receiver guts with new modern stuff,
which you can get in kit-form on E-Bay or Ali-Express.
All of the cheapo factory Capacitors will be either shorted, or leaking from age,
and the super cheap resistors are probably noisy as hell,
with values drifting all over the place from humidity and age,
not to mention bad solder joints, corrosion, and super cheap printed circuit boards.
If it was a Tube (Valve) Amp, I'd say to restore it, but not an old Transistor Amp,
( most especially not a cheap Class-A Amp ),
they were designed to be built absolutely as dirt-cheap as humanly possible,
which makes them not worth the time, headaches, and money to restore them.
And, you really should replace the speakers at the same time,
you can get quality speakers cheap at Parts-Express.
.
.
I starting to think that's is going to be best solution rt I Just trying bring this amp back to life with a little of the money but if I can't your solution its best thanks so much
 

RPLaJeunesse

Joined Jul 29, 2018
139
Is the emitter connected to the battery lead, possibly through a small resistor? If yes then it's a PNP part. Look for a PNP germanium in the same package, good for >=5A and >=30V Vce. Could be a 2N174 would do nicely.
 
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