QUESTION: Yamaha MX-1000 Power Amplifier Problem

QUESTION: Yamaha MX-1000 Power Amplifier Problem


I recently acquired a used Yamaha MX-1000 Power Amplifier that was
VERY dirty.

I opened it up and found probably 3 cats' worth of fur covering the
components inside. You could barely identify the various capacitors,
resistors, etc.

I am no stranger to cleaning out dirty audio gear, and so I took my
trusty Hoover and **CAREFULLY** vacuumed out all of the fuzz and lint
I could see. I also used a small paintbrush as a miniature whisk
broom to get in the tighter areas.

I was very, VERY careful not to disturb any wiring connections.

I carefully put the top cover back on and used the amplifier for a
couple of days with no problems whatsoever.

But now I have noticed that the digital wattage readout on the front
of the amp no longer lights up. I believe that it DID light up
normally after I re-assembled the amplifier, but I still can't help
wondering if I did something to break a connection somewhere.

Does anyone have a schematic for this amplifier? It's really not a
very important feature, but it bothers me that it no longer works.

Is this a common problem on these amplifiers?

Any assistance will be GREATLY appreciated! Thanks in
advance..........

Re: QUESTION: Yamaha MX-1000 Power Amplifier Problem

You mean the illumination for the meter is out or the meter doesn't work?

Vacuum cleaners generate static and are not the best things for cleaning.
Compressed air is better.

"EADGBE" <hwbosshoss@comcast,net > wrote in message
news:be8e9d59-3273-47dc-9acb-7d597221343e@8g2000hse.googlegroups,com ...
>
> I recently acquired a used Yamaha MX-1000 Power Amplifier that was
> VERY dirty.
>
> I opened it up and found probably 3 cats' worth of fur covering the
> components inside. You could barely identify the various capacitors,
> resistors, etc.
>
> I am no stranger to cleaning out dirty audio gear, and so I took my
> trusty Hoover and **CAREFULLY** vacuumed out all of the fuzz and lint
> I could see. I also used a small paintbrush as a miniature whisk
> broom to get in the tighter areas.
>
> I was very, VERY careful not to disturb any wiring connections.
>
> I carefully put the top cover back on and used the amplifier for a
> couple of days with no problems whatsoever.
>
> But now I have noticed that the digital wattage readout on the front
> of the amp no longer lights up. I believe that it DID light up
> normally after I re-assembled the amplifier, but I still can't help
> wondering if I did something to break a connection somewhere.
>
> Does anyone have a schematic for this amplifier? It's really not a
> very important feature, but it bothers me that it no longer works.
>
> Is this a common problem on these amplifiers?
>
> Any assistance will be GREATLY appreciated! Thanks in
> advance..........
>

Re: QUESTION: Yamaha MX-1000 Power Amplifier Problem

On Jun 17, 10:06 pm, "jamesgangnc" <ja...@nospam,com > wrote:
> You mean the illumination for the meter is out or the meter doesn't work?
>
> Vacuum cleaners generate static and are not the best things for cleaning.
> Compressed air is better.

The meters, which are a liquid-crystal type, both work fine. The
display lamps which illuminate the meter wattage scale all work fine,
too.

The part that is NOT working is the LED digital readout showing the
output wattage. This is located between the meters and should always
be on whenever the amplifier is on.

Re: QUESTION: Yamaha MX-1000 Power Amplifier Problem

"EADGBE" <hwbosshoss@comcast,net > wrote in message
news:a1fca10e-7b54-4a73-ab6b-3e74bdb0c42e@2g2000hsn.googlegroups,com ...
> On Jun 17, 10:06 pm, "jamesgangnc" <ja...@nospam,com > wrote:
>> You mean the illumination for the meter is out or the meter doesn't work?
>>
>> Vacuum cleaners generate static and are not the best things for cleaning.
>> Compressed air is better.
>
> The meters, which are a liquid-crystal type, both work fine. The
> display lamps which illuminate the meter wattage scale all work fine,
> too.
>
> The part that is NOT working is the LED digital readout showing the
> output wattage. This is located between the meters and should always
> be on whenever the amplifier is on.
>
I'm not familiar with that particular amp but I do know that some of those
led watt meters need to have speakers connected and the volume cranked up a
bit to work. Otherwise sounds like it's broken. I've had very little luck
in general finding free schematics on the net. I have bought a few as there
are lots of sites that sell them at a fairly reasonable price and you
download them immediately after you pay. For equipment that I plan to keep
I figure it's not unreasonable to think I might need the schematic again. A
lot of those meters are pretty simple and you may be able to trace the led
connections back to a board and follow the traces to a chip. Or the chip
might be on the back of the board the led is mounted on. With a part number
off the chip you could get a good idea what voltages to expect where. Most
of the chip data is online and is free if you search for it. I use the
suppliers sites and they usually have links to the chip data sheet.

I would not assume your cleaning resulted in it being broken but again,
vacuum cleaners make a lot of static. I use compressed air and if it is too
dirty for that I remove the board and wash it with mild soap and water.
Then compressed air and allow to dry for a day.

Re: QUESTION: Yamaha MX-1000 Power Amplifier Problem

On Jun 18, 8:02 am, "jamesgangnc" <ja...@nospam,com > wrote:
>
> I would not assume your cleaning resulted in it being broken but again,
> vacuum cleaners make a lot of static. I use compressed air and if it is too
> dirty for that I remove the board and wash it with mild soap and water.
> Then compressed air and allow to dry for a day.

Thanks for the advice.

The frustrating thing is that I took such great pains not to let the
nozzle of the Hoover to actually come in contact with anything. I
merely held it above the circuit boards whilst I gently swept around
the components with the small artist's brush. The idea was to loosen
all of the lint and dust (and there was a TON of it) so that the
Hoover could grab it and suck it away.

But I still feel that I must have disturbed something, even though I
was quite obsessive about having the lightest touch possible.

Re: QUESTION: Yamaha MX-1000 Power Amplifier Problem


"EADGBE" <hwbosshoss@comcast,net > wrote in message
news:5704fcc8-b55a-4674-bd65-cb839ce5271f@d45g2000hsc.googlegroups,com ...
> On Jun 18, 8:02 am, "jamesgangnc" <ja...@nospam,com > wrote:
>>
>> I would not assume your cleaning resulted in it being broken but again,
>> vacuum cleaners make a lot of static. I use compressed air and if it is
>> too
>> dirty for that I remove the board and wash it with mild soap and water.
>> Then compressed air and allow to dry for a day.
>
> Thanks for the advice.
>
> The frustrating thing is that I took such great pains not to let the
> nozzle of the Hoover to actually come in contact with anything. I
> merely held it above the circuit boards whilst I gently swept around
> the components with the small artist's brush. The idea was to loosen
> all of the lint and dust (and there was a TON of it) so that the
> Hoover could grab it and suck it away.
>
> But I still feel that I must have disturbed something, even though I
> was quite obsessive about having the lightest touch possible.
>
If you think it's worthwhile fixing and you want a manual, try
vintageaudiomanuals,com
email mike@vintageaudiomanuals,com

I recently bought a manual for a Yamaha CR1000 receiver I'd been given and
it came delivered to my door in the UK in a week, for the princely sum of
USD25.00 Could be cheaper than that depending on how big the manual is, and
where you are located. (Vintageaudiomanuals are in Oregon)

Although it is a copy, the reproduction and binding looks like an original,
and the circuit diagrams are also on CD.

S.
--
http :// audiopages.googlepages,com

Re: QUESTION: Yamaha MX-1000 Power Amplifier Problem

On Jun 18, 10:04 am, EADGBE <hwbossh...@comcast,net > wrote:
> On Jun 18, 8:02 am, "jamesgangnc" <ja...@nospam,com > wrote:
>
>
>
> > I would not assume your cleaning resulted in it being broken but again,
> > vacuum cleaners make a lot of static.  I use compressed air and if it is too
> > dirty for that I remove the board and wash it with mild soap and water.
> > Then compressed air and allow to dry for a day.
>
> Thanks for the advice.
>
> The frustrating thing is that I took such great pains not to let the
> nozzle of the Hoover to actually come in contact with anything.  I
> merely held it above the circuit boards whilst I gently swept around
> the components with the small artist's brush.  The idea was to loosen
> all of the lint and dust (and there was a TON of it) so that the
> Hoover could grab it and suck it away.
>
> But I still feel that I must have disturbed something, even though I
> was quite obsessive about having the lightest touch possible.

But you were holding the vacuum nozzle and touching the board.

Re: QUESTION: Yamaha MX-1000 Power Amplifier Problem

The artist's brush with the high velocity air that is under suction
makes for an excellent static generator! This can cause damage
especially to CMOS type devices in the amplifier.

Check to see if there is at least supply voltage coming to the IC and
relevant parts of the circuit board that is driving the LED's.

--

JANA
_____


"EADGBE" <hwbosshoss@comcast,net > wrote in message
news:5704fcc8-b55a-4674-bd65-cb839ce5271f@d45g2000hsc.googlegroups,com ...
On Jun 18, 8:02 am, "jamesgangnc" <ja...@nospam,com > wrote:
>
> I would not assume your cleaning resulted in it being broken but
> again,
> vacuum cleaners make a lot of static. I use compressed air and if it
> is too
> dirty for that I remove the board and wash it with mild soap and
> water.
> Then compressed air and allow to dry for a day.

Thanks for the advice.

The frustrating thing is that I took such great pains not to let the
nozzle of the Hoover to actually come in contact with anything. I
merely held it above the circuit boards whilst I gently swept around
the components with the small artist's brush. The idea was to loosen
all of the lint and dust (and there was a TON of it) so that the
Hoover could grab it and suck it away.

But I still feel that I must have disturbed something, even though I
was quite obsessive about having the lightest touch possible.

Re: QUESTION: Yamaha MX-1000 Power Amplifier Problem

On Jun 20, 2:47 am, "JANA" <j...@NOSPAMca.inter,net > wrote:
> The artist's brush with the high velocity air that is under suction
> makes for an excellent static generator! This can cause damage
> especially to CMOS type devices in the amplifier.
>
> Check to see if there is at least supply voltage coming to the IC and
> relevant parts of the circuit board that is driving the LED's.

Thanks for your input, JANA. Boy, now I feel foolish! But you should
have seen the amount of lint, fur, and dust inside this amp. It
literally looked as if the amp had had a miniature snowstorm inside of
it. I didn't know what else to do. At least the amplifier portion
seems to be OK, and so do the LCD level meters. The LED digital
readout is the only "casualty".

Re: QUESTION: Yamaha MX-1000 Power Amplifier Problem


"EADGBE" <hwbosshoss@comcast,net > wrote in message
news:be8e9d59-3273-47dc-9acb-7d597221343e@8g2000hse.googlegroups,com ...
>
.
>
> But now I have noticed that the digital wattage readout on the front
> of the amp no longer lights up. I believe that it DID light up
> normally after I re-assembled the amplifier, but I still can't help
> wondering if I did something to break a connection somewhere.
>

I had an MX-800, same case, same meters... I always hated those giant red
meters, found them cheap-looking and gaudy. I was very happy when they
stopped working, probably when the amp was about 10 years old. In fact I
think that amp is still in my basement.