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-   -   Toshiba sa-500 receiver (http://www.collectingbanter.com/showthread.php?t=252566)

carfreak July 9th 08 04:34 AM

Toshiba sa-500 receiver
 
I was recommended to go here by rusty . I am new to vintage audio,
and recently got a toshiba sa-500. It has a pretty bad balance
issue. I have to turn the knob to 3 on the right for it to be
balanced. Any solutions?

DeserTBoB July 9th 08 09:22 PM

Toshiba sa-500 receiver
 
On Tue, 8 Jul 2008 20:34:35 -0700 (PDT), carfreak
wrote:

I was recommended to go here by rusty . I am new to vintage audio,
and recently got a toshiba sa-500. It has a pretty bad balance
issue. I have to turn the knob to 3 on the right for it to be
balanced. Any solutions? snip


First, swap the speaker leads and see if the trouble follows the
speaker. You may have a loudspeaker issue, not an electrical issue.
If the trouble doesn't follow the speaker, you could have a number of
different problems, a likely one being a toasted output transistor,
which would make the channel in question about 6 dB less loud than the
good one. You don't say if the affected channel has a distortion
problem or not, which could alos be an indicator.

These weren't very good units, so don't go spending a lot of money
fixing it. Toshiba's audio products were, around that time, discount
store stuff at best. Their cassette decks were some of the worst I've
ever seen at any price.

Rusty July 9th 08 10:20 PM

Toshiba sa-500 receiver
 
On Jul 9, 1:22 pm, DeserTBoB wrote:
On Tue, 8 Jul 2008 20:34:35 -0700 (PDT), carfreak

wrote:
I was recommended to go here by rusty . I am new to vintage audio,
and recently got a toshiba sa-500. It has a pretty bad balance
issue. I have to turn the knob to 3 on the right for it to be
balanced. Any solutions? snip


First, swap the speaker leads and see if the trouble follows the
speaker. You may have a loudspeaker issue, not an electrical issue.
If the trouble doesn't follow the speaker, you could have a number of
different problems, a likely one being a toasted output transistor,
which would make the channel in question about 6 dB less loud than the
good one. You don't say if the affected channel has a distortion
problem or not, which could alos be an indicator.

These weren't very good units, so don't go spending a lot of money
fixing it. Toshiba's audio products were, around that time, discount
store stuff at best. Their cassette decks were some of the worst I've
ever seen at any price.


we did switch the speaker leads. that was the first thing we did. the
speaker was not the issue. the receiver has a lot of sentimental value
to my friend it belonged to his grandparents. how hard is it to switch
out the output transistor?

Rusty

DeserTBoB July 10th 08 01:14 AM

Toshiba sa-500 receiver
 
On Wed, 9 Jul 2008 14:20:57 -0700 (PDT), Rusty
wrote:

we did switch the speaker leads. that was the first thing we did. the
speaker was not the issue. the receiver has a lot of sentimental value
to my friend it belonged to his grandparents. how hard is it to switch
out the output transistor? snip


OK, this unit (I believe) has a speaker selection switch. Try running
from the "B" speaker terminals and see if the problem still stays the
same.

Replacing a standard TO3-case output transistor is quick work, but
first you have to know how to find the bad one. Tools would be a
soldering iron, thermal grease and normal screwdrivers, side cutters,
et al. I really don't have the JEDEC number of the original outputs
on those handy, but suffice it to say that, if failed, the bad
transistor won't be shorted, since the amplifier is still operating.
I'd look for oxidized connections on the output transistor heat sink.
Also, be aware that Japanese electronics from this era were well known
for developing cracked solder on their wave-soldiered PC boards, but I
don't think that's the issue here.

carfreak July 10th 08 05:52 AM

Toshiba sa-500 receiver
 
On Jul 9, 5:14*pm, DeserTBoB wrote:
On Wed, 9 Jul 2008 14:20:57 -0700 (PDT), Rusty

wrote:
we did switch the speaker leads. that was the first thing we did. the
speaker was not the issue. the receiver has a lot of sentimental value
to my friend it belonged to his grandparents. how hard is it to switch
out the output transistor? snip


OK, this unit (I believe) has a speaker selection switch. *Try running
from the "B" speaker terminals and see if the problem still stays the
same.

Replacing a standard TO3-case output transistor is quick work, but
first you have to know how to find the bad one. *Tools would be a
soldering iron, thermal grease and normal screwdrivers, side cutters,
et al. *I really don't have the JEDEC number of the original outputs
on those handy, but suffice it to say that, if failed, the bad
transistor won't be shorted, since the amplifier is still operating.
I'd look for oxidized connections on the output transistor heat sink.
Also, be aware that Japanese electronics from this era were well known
for developing cracked solder on their wave-soldiered PC boards, but I
don't think that's the issue here.


My receiver hasn't been used in probably over a decade, so oxidation
is very possible. I will check it out, thanks for the advice. If I
do find oxidation, how should I clean it?

DeserTBoB July 10th 08 05:20 PM

Toshiba sa-500 receiver
 
On Wed, 9 Jul 2008 21:52:35 -0700 (PDT), carfreak
wrote:

My receiver hasn't been used in probably over a decade, so oxidation
is very possible. I will check it out, thanks for the advice. If I
do find oxidation, how should I clean it? snip


On wafer switches, the best first aid is simply exercising them. For
noisy switches and pots, a switch contact cleaning spray, notably
those from Caig Laboratories (Caig Pro Gold is a favorite of mine), is
best, but don't overdo it. Washing potentiometers and switches too
much will wash out all the "pot grease" and the oxidation will return
shortly, along with erratic performance.

Also of concern, if the unit has been sitting around unenergized, is
the condition of any electrolytic capacitors in the unit. Usually,
this will manifest itself in "crackling and popping" noises, if the
power supply electrolytics are bad. Most of the older Japanese
receivers of this ilk used Nichicon axial electrolytics in for stage
decoupling, and they do tend to go bad. Job 1 right now, though, is
tracking down why one channel is performing badly. Good luck with
that.

trippin-2-8-track July 10th 08 08:13 PM

Toshiba sa-500 receiver
 
My receiver hasn't been used in probably over a decade, so oxidation
is very possible. *I will check it out, thanks for the advice. *If I
do find oxidation, how should I clean it?- Hide quoted text -

- Show quoted text -



carfreak check your email, I sent you one

DeserTBoB July 11th 08 01:04 AM

Toshiba sa-500 receiver
 
On Thu, 10 Jul 2008 12:13:43 -0700 (PDT), "Dishwasher Charlie" Nudo,
Drums, PA aka trippin-2-8-track wrote:

My receiver hasn't been used in probably over a decade, so oxidation
is very possible. *I will check it out, thanks for the advice. *If I
do find oxidation, how should I clean it?- Hide quoted text -

- Show quoted text -



carfreak check your email, I sent you one snip


Why do you have to "announce" that you sent someone an email, if but
only to say that you've sent yet another lie-filled attack against me
to him? Do you think you're fooling anyone with your crap? No one is
fooled. The only "fool" here is "Dishwasher Charlie" Nudo, the
simpleton from Drums.

carfreak July 11th 08 02:44 AM

Toshiba sa-500 receiver
 
On Jul 10, 5:04*pm, DeserTBoB wrote:
On Thu, 10 Jul 2008 12:13:43 -0700 (PDT), "Dishwasher Charlie" Nudo,
Drums, PA *aka trippin-2-8-track wrote:

My receiver hasn't been used in probably over a decade, so oxidation
is very possible. *I will check it out, thanks for the advice. *If I
do find oxidation, how should I clean it?- Hide quoted text -


- Show quoted text -


carfreak check your email, I sent you one snip


Why do you have to "announce" that you sent someone an email, if but
only to say that you've sent yet another lie-filled attack against me
to him? *Do you think you're fooling anyone with your crap? *No one is
fooled. *The only "fool" here is "Dishwasher Charlie" Nudo, the
simpleton from Drums.


sorry to ruin your fun, desertbob, but it wasnt what you think. it
was advice along with an offer to repair my receiver for a cost.

DeserTBoB July 11th 08 03:35 AM

Toshiba sa-500 receiver
 
On Thu, 10 Jul 2008 18:44:55 -0700 (PDT), carfreak
wrote:

sorry to ruin your fun, desertbob, but it wasnt what you think. it
was advice along with an offer to repair my receiver for a cost. snip


Usually, he sends diatribes to others about his "enemies," as people
send me the mail they get from him. Consider yourself lucky in that
regard, but this guy Charlie Nudo is NO electronics technician. What
the game is with Noodles is that he's hooked in with the owner of a
dying electronics shop in Hazelton, PA. Noodles takes your unit to
him, has the dude repair it, and then tacks on his take on top of it.
You'd be far better off taking it to someone local to you...assuming
you can find one. Even if you go for online repair, better to send
the unit directly to this guy's shop rather than go through our
resident scumbag.


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