I posted some time back about powering up the SX-434 reciever after it
had been unpowered for some years. Using a variac I slowly brought the
power up. Then today I plugged an mp3 player into it and wired up some
speakers and it sounds great! Thanks for the advice folks. BTW, I took
the cover off to look inside for anything amiss. It was all clean
inside, no corrosion, nests, bugs, or bulging caps. There are two
devices that look to me like tubes with metal cans over them. Did this
thing really have a couple tubes in it?
Thanks,
Eric

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I posted some time back about powering up the SX-434 reciever after it
had been unpowered for some years. Using a variac I slowly brought the
power up. Then today I plugged an mp3 player into it and wired up some
speakers and it sounds great! Thanks for the advice folks. BTW, I took
the cover off to look inside for anything amiss. It was all clean
inside, no corrosion, nests, bugs, or bulging caps. There are two
devices that look to me like tubes with metal cans over them. Did this
thing really have a couple tubes in it?

Sony SX-434 (for which I find no references) or Pioneer SX-434?

The Pioneer SX-434 doesn't appear to have any vaccum tubes, according
to the service manual. It does have a couple of large electrolyic
filter capacitors - 3300 microfarads, 25 volts "working volts". These
are located along the left side of the metal chassis, nearer the front
than the back, right in front of the big squarish power transformer.

I'm a trifle disappointed, though... the schematic says that the "no
signal" voltage on those power supply rails is +/- 24 volts. That's
very close to the maximum rating of these caps... not much safety
margin. If you ever have this receiver in for service (or want to
play with it yourself), it might be worth replacing these caps with
3300 (or a bit larger) 35-volt caps, just to make sure they aren't
ever overvoltaged and shorted out by a momentary surge in your
powerline voltage.

wrote:
I posted some time back about powering up the SX-434 reciever after it
had been unpowered for some years. Using a variac I slowly brought the
power up. Then today I plugged an mp3 player into it and wired up some
speakers and it sounds great!

Thanks for posting back with results! It helps everybody calibrate
their advice for next time.

There are two devices that look to me like tubes with metal cans over
them. Did this thing really have a couple tubes in it?

Probably not. Those are probably the electrolytic filter capacitors for
the main positive and negative power supplies. Most smaller electrolytic
capacitors of that vintage have a plastic sleeve (often blue, green, or
black, but anything is possible) over the metal can. Some of the larger
ones didn't have plastic outer sleeves then - usually it was just plain
aluminum. Usually there is a size and voltage rating either stamped
into or printed onto the aluminum.

If there is something like "3300 uF, 50 V" printed on the cans - the
numbers may vary but the "uF" and "V" marks will be there - then these
are indeed the capacitors. They may also have a "+ + +" or "- - -" or
a stripe to indicate polarity.

Matt Roberds

There are two
devices that look to me like tubes with metal cans over them.


** The cans are square - right ?

And in the tuner section.

IF transformers have such cans over them.



..... Phil

On Mon, 24 Mar 2014 17:13:24 -0700, (David
Platt) wrote:


I posted some time back about powering up the SX-434 reciever after it
had been unpowered for some years. Using a variac I slowly brought the
power up. Then today I plugged an mp3 player into it and wired up some
speakers and it sounds great! Thanks for the advice folks. BTW, I took
the cover off to look inside for anything amiss. It was all clean
inside, no corrosion, nests, bugs, or bulging caps. There are two
devices that look to me like tubes with metal cans over them. Did this
thing really have a couple tubes in it?

Sony SX-434 (for which I find no references) or Pioneer SX-434?

The Pioneer SX-434 doesn't appear to have any vaccum tubes, according
to the service manual. It does have a couple of large electrolyic
filter capacitors - 3300 microfarads, 25 volts "working volts". These
are located along the left side of the metal chassis, nearer the front
than the back, right in front of the big squarish power transformer.

I'm a trifle disappointed, though... the schematic says that the "no
signal" voltage on those power supply rails is +/- 24 volts. That's
very close to the maximum rating of these caps... not much safety
margin. If you ever have this receiver in for service (or want to
play with it yourself), it might be worth replacing these caps with
3300 (or a bit larger) 35-volt caps, just to make sure they aren't
ever overvoltaged and shorted out by a momentary surge in your
powerline voltage.



Sony, hmmm. Yeah, that was baloney. The reciever is indeed a Pioneer.
Don't know why I though it was a Sony. Thanks for the info about the
"tubes". The items described by you and their location match what's in
the thing.
Thanks,
Eric

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On Tue, 25 Mar 2014 01:25:22 +0000 (UTC), wrote:

wrote:
I posted some time back about powering up the SX-434 reciever after it
had been unpowered for some years. Using a variac I slowly brought the
power up. Then today I plugged an mp3 player into it and wired up some
speakers and it sounds great!

Thanks for posting back with results! It helps everybody calibrate
their advice for next time.

There are two devices that look to me like tubes with metal cans over
them. Did this thing really have a couple tubes in it?

Probably not. Those are probably the electrolytic filter capacitors for
the main positive and negative power supplies. Most smaller electrolytic
capacitors of that vintage have a plastic sleeve (often blue, green, or
black, but anything is possible) over the metal can. Some of the larger
ones didn't have plastic outer sleeves then - usually it was just plain
aluminum. Usually there is a size and voltage rating either stamped
into or printed onto the aluminum.

If there is something like "3300 uF, 50 V" printed on the cans - the
numbers may vary but the "uF" and "V" marks will be there - then these
are indeed the capacitors. They may also have a "+ + +" or "- - -" or
a stripe to indicate polarity.

Matt Roberds
As it turns out David Platt also correctly identified them as caps.
Thanks,
Eric

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