SPS5384 transistor and noise

S

Sverre Holm

Guest
I have repaired a 70's vintage hi-fi tuner/amplifier that looked as if
lightning had hit the speaker wires, a Tandberg Huldra 10. The finals are
MJE2955/MJE3055, the drivers MPSU06/MPSU56, and the pre-driver stage an
SPS5384 (Motorola?).

I have found exact replacements for the finals, and replaced the drivers
with TIP31C/TIP32C.

I could not find any data for the SPS5384, so I replaced it with a TIP31C
which is NPN and can take 100 Volts. I find now that the amplifier is more
noisy with the volume control set low than it should be. I am assuming that
this comes from the pre-driver stage.

My question is if anyone know any data for the SPS5384, and can suggest
replacements.


Thanks,

Sverre
www.qsl.net/la3za
 
Sverre Holm wrote:
I have repaired a 70's vintage hi-fi tuner/amplifier that looked as if
lightning had hit the speaker wires, a Tandberg Huldra 10. The finals
are MJE2955/MJE3055, the drivers MPSU06/MPSU56, and the pre-driver
stage an SPS5384 (Motorola?).

I have found exact replacements for the finals, and replaced the
drivers with TIP31C/TIP32C.

I could not find any data for the SPS5384, so I replaced it with a
TIP31C which is NPN and can take 100 Volts. I find now that the
amplifier is more noisy with the volume control set low than it
should be. I am assuming that this comes from the pre-driver stage.

My question is if anyone know any data for the SPS5384, and can
suggest replacements.
How are the components in the negative feedback loop? Have any
resistors been cooked? An open circuit feedback loop can put the
gain up in the output stages.

I haven't located what an SPS5384 is.

73 de G3VPC
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How are the components in the negative feedback loop? Have any
resistors been cooked? An open circuit feedback loop can put the
gain up in the output stages.
Good suggestion, but wouldn't that show up as too much overall gain in the
amplifier? Mine plays normally, and also equally in both channels, therefore
I have up to now thought that the feedback loop is OK.


Sverre
 
Graham W wrote:
Sverre Holm wrote:
I have repaired a 70's vintage hi-fi tuner/amplifier that looked as if
lightning had hit the speaker wires, a Tandberg Huldra 10. The finals
are MJE2955/MJE3055, the drivers MPSU06/MPSU56, and the pre-driver
stage an SPS5384 (Motorola?).

I have found exact replacements for the finals, and replaced the
drivers with TIP31C/TIP32C.

I could not find any data for the SPS5384, so I replaced it with a
TIP31C which is NPN and can take 100 Volts. I find now that the
amplifier is more noisy with the volume control set low than it
should be. I am assuming that this comes from the pre-driver stage.

My question is if anyone know any data for the SPS5384, and can
suggest replacements.

How are the components in the negative feedback loop? Have any
resistors been cooked? An open circuit feedback loop can put the
gain up in the output stages.

I haven't located what an SPS5384 is.

73 de G3VPC
--
SPSxxxx are house branded parts made by Motorola. You have to get
replacements from the OEM, or figure out the specs for the original part
and choose a replacement.

--


Michael A. Terrell
Central Florida
 
In article <pwRhb.29812$os2.435368@news2.e.nsc.no>,
la3za.0junk4me@qsl.net mentioned...
I have repaired a 70's vintage hi-fi tuner/amplifier that looked as if
lightning had hit the speaker wires, a Tandberg Huldra 10. The finals are
MJE2955/MJE3055, the drivers MPSU06/MPSU56, and the pre-driver stage an
SPS5384 (Motorola?).

I have found exact replacements for the finals, and replaced the drivers
with TIP31C/TIP32C.

I could not find any data for the SPS5384, so I replaced it with a TIP31C
which is NPN and can take 100 Volts. I find now that the amplifier is more
noisy with the volume control set low than it should be. I am assuming that
this comes from the pre-driver stage.

My question is if anyone know any data for the SPS5384, and can suggest
replacements.
You gave no indication of what package it's in, or pinouts, heatsink,
etc. Maybe something like the BD139 / BD140 in the TO-126 package
would work okay. They're cheap, way under a dollar (US).


Thanks,

Sverre
www.qsl.net/la3za

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The MPSU06/56 and the SPS5384 all have the same package. It is a package
which I haven't seen for a long time. A kind of medium power package with a
blank brass metal tab sticking up with a screw hole. The pin-out is EBC, so
the TIP31C/32C which I used for MPSU06/56 had to have two legs crossed to
fit in the PCB.

Sverre

the drivers MPSU06/MPSU56, and the pre-driver stage an
SPS5384 (Motorola?).

You gave no indication of what package it's in, or pinouts, heatsink,
etc. Maybe something like the BD139 / BD140 in the TO-126 package
would work okay. They're cheap, way under a dollar (US).
@n@t@@m@e@e@t@@t@h@e@@E@f@f@l@u@e@n@t@@
 

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