A Nonfunctioning 100gx -- Something new

#265

Hello, folks.

So my repair guy tapped on the relay, it thunked, and he plugged it in and
pressed the power button. A capacitor right by the front power button got
hot and let all its smoke out. This can be a couple of things -- that cap
was needing replacement due to age, so it failed when power got into the
system. Or there's something else wrong that overloaded that cap. There's
also the biggest list of possible reasons -- something I don't know about.

Anyone got any ideas?
Nicole

Sent from my HAL 9000 in transit to Jupiter

#266

Probably one of safety caps avoiding sparkles when switching on. They can die this way after years and sometimes even cause the fire. Just replace it, it will be OK. Another one can be somewhere in PSU primary circuit, replace it as well.

Daniel Forro

Show quoted text

On Aug 5, 2024, at 6:47, Nicole Massey <nyyki@...> wrote:

Hello, folks.

So my repair guy tapped on the relay, it thunked, and he plugged it in and
pressed the power button. A capacitor right by the front power button got
hot and let all its smoke out. This can be a couple of things -- that cap
was needing replacement due to age, so it failed when power got into the
system. Or there's something else wrong that overloaded that cap. There's
also the biggest list of possible reasons -- something I don't know about.

Anyone got any ideas?
Nicole

#267

An electrolytic capacitor (like other caps) stores energy. An applied load cannot normally cause a capacitor to fail. It had to get hot internally to let its smoke out. My first thoughts, based on your reports, is that the relay was probably stuck (tapping it caused it to pick up) and when the circuit energized (assume it is the audio out, because the relay enables audio out) the capacitor failed.

I do not have a schematic to see what else is in the circuit where the cap failed. If it is in a DC power circuit (most likely), the possibility exists that it may be a faulty diode (changes AC to DC) blasting a DC electrolytic capacitor with raw AC (rather than pulsating DC) would result in failure, could also be a circuit board trace problem (known issue) around the power supply area.?

FWIW, YMMV

Heather

#268

So, what I would do if this were mine, is, replace all the Caps including the ones on the Power Supply board. Check the diodes for any defects such as reverse voltage.  Diodes will give a reading in only one direction e.g. anode to cathode.  Also replace the output relay, since it kicked, it’s sticking inside.  
Patrick

Show quoted text

On Aug 4, 2024, at 8:54?PM, Daniel Forró via groups.io <danforcz@...> wrote:

?Probably one of safety caps avoiding sparkles when switching on. They can die this way after years and sometimes even cause the fire. Just replace it, it will be OK. Another one can be somewhere in PSU primary circuit, replace it as well.

Daniel Forro


On Aug 5, 2024, at 6:47, Nicole Massey <nyyki@...> wrote:

Hello, folks.

So my repair guy tapped on the relay, it thunked, and he plugged it in and
pressed the power button. A capacitor right by the front power button got
hot and let all its smoke out. This can be a couple of things -- that cap
was needing replacement due to age, so it failed when power got into the
system. Or there's something else wrong that overloaded that cap. There's
also the biggest list of possible reasons -- something I don't know about.

Anyone got any ideas?
Nicole

#269

Yep. He's doing all of this, and with luck I'll have a functioning GX I can sample -- my live rig is a lot more portable, and I need a bank of GX sounds for that, with a couple very important. This machine is destined to be a bass box -- I've got a sysex file of different bass sounds culled from a lot of sound banks.
Nicole

Show quoted text

-----Original Message-----
From: [email protected] <[email protected]> On Behalf Of fop29, via groups.io
Sent: Tuesday, August 6, 2024 8:12 AM
To: [email protected]
Subject: Re: [K1000-K1200] A Nonfunctioning 100gx -- Something new

So, what I would do if this were mine, is, replace all the Caps including the ones on the Power Supply board. Check the diodes for any defects such as reverse voltage.  Diodes will give a reading in only one direction e.g. anode to cathode.  Also replace the output relay, since it kicked, it’s sticking inside.  
Patrick

On Aug 4, 2024, at 8:54?PM, Daniel Forró via groups.io <danforcz@...> wrote:

?Probably one of safety caps avoiding sparkles when switching on. They can die this way after years and sometimes even cause the fire. Just replace it, it will be OK. Another one can be somewhere in PSU primary circuit, replace it as well.

Daniel Forro

On Aug 5, 2024, at 6:47, Nicole Massey <nyyki@...> wrote:

Hello, folks.

So my repair guy tapped on the relay, it thunked, and he plugged it 
in and pressed the power button. A capacitor right by the front power 
button got hot and let all its smoke out. This can be a couple of 
things -- that cap was needing replacement due to age, so it failed 
when power got into the system. Or there's something else wrong that 
overloaded that cap. There's also the biggest list of possible reasons -- something I don't know about.

Anyone got any ideas?
Nicole

#270

Hope it works out!

Show quoted text

On Aug 6, 2024, at 9:12?AM, fop29, via groups.io <fop29@...> wrote:

?So, what I would do if this were mine, is, replace all the Caps including the ones on the Power Supply board. Check the diodes for any defects such as reverse voltage.  Diodes will give a reading in only one direction e.g. anode to cathode.  Also replace the output relay, since it kicked, it’s sticking inside.  
Patrick

On Aug 4, 2024, at 8:54?PM, Daniel Forró via groups.io <danforcz@...> wrote:

?Probably one of safety caps avoiding sparkles when switching on. They can die this way after years and sometimes even cause the fire. Just replace it, it will be OK. Another one can be somewhere in PSU primary circuit, replace it as well.

Daniel Forro


On Aug 5, 2024, at 6:47, Nicole Massey <nyyki@...> wrote:Hello, folks.

So my repair guy tapped on the relay, it thunked, and he plugged it in and
pressed the power button. A capacitor right by the front power button got
hot and let all its smoke out. This can be a couple of things -- that cap
was needing replacement due to age, so it failed when power got into the
system. Or there's something else wrong that overloaded that cap. There's
also the biggest list of possible reasons -- something I don't know about.

Anyone got any ideas?
Nicole

#271

Okay, another question -- assuming I can get this up and running again, is there anyone who can burn OS 5.x into chips for it?
Nicole

Show quoted text

-----Original Message-----
From: [email protected] <[email protected]> On Behalf Of fop29, via groups.io
Sent: Tuesday, August 6, 2024 5:44 PM
To: [email protected]
Subject: Re: [K1000-K1200] A Nonfunctioning 100gx -- Something new

Hope it works out! 
On Aug 6, 2024, at 9:12?AM, fop29, via groups.io <fop29@...> wrote:

?So, what I would do if this were mine, is, replace all the Caps including the ones on the Power Supply board. Check the diodes for any defects such as reverse voltage.  Diodes will give a reading in only one direction e.g. anode to cathode.  Also replace the output relay, since it kicked, it’s sticking inside.  
Patrick

On Aug 4, 2024, at 8:54?PM, Daniel Forró via groups.io <danforcz@...> wrote:

?Probably one of safety caps avoiding sparkles when switching on. They can die this way after years and sometimes even cause the fire. Just replace it, it will be OK. Another one can be somewhere in PSU primary circuit, replace it as well.

Daniel Forro

On Aug 5, 2024, at 6:47, Nicole Massey <nyyki@...> wrote:Hello, folks.

So my repair guy tapped on the relay, it thunked, and he plugged it 
in and pressed the power button. A capacitor right by the front 
power button got hot and let all its smoke out. This can be a couple 
of things -- that cap was needing replacement due to age, so it 
failed when power got into the system. Or there's something else 
wrong that overloaded that cap. There's also the biggest list of possible reasons -- something I don't know about.

Anyone got any ideas?
Nicole

#272

That’s a tough one.  I don’t know anyone that does that.  Maybe someone in the group may know someone.
Did it have sounds prior to the current issue?  If not, or they are garbled nonsense, have your tech pull the socketed IC’s and clean the pins.  
I had to do that on my 1000 SX.  
Patrick

Show quoted text

On Aug 6, 2024, at 10:35?PM, Nicole Massey <nyyki@...> wrote:

?Okay, another question -- assuming I can get this up and running again, is there anyone who can burn OS 5.x into chips for it?
Nicole

-----Original Message-----
From: [email protected] <[email protected]> On Behalf Of fop29, via groups.io
Sent: Tuesday, August 6, 2024 5:44 PM
To: [email protected]
Subject: Re: [K1000-K1200] A Nonfunctioning 100gx -- Something new

Hope it works out!
On Aug 6, 2024, at 9:12?AM, fop29, via groups.io <fop29@...> wrote:

?So, what I would do if this were mine, is, replace all the Caps including the ones on the Power Supply board. Check the diodes for any defects such as reverse voltage.  Diodes will give a reading in only one direction e.g. anode to cathode.  Also replace the output relay, since it kicked, it’s sticking inside.  
Patrick

On Aug 4, 2024, at 8:54?PM, Daniel Forró via groups.io <danforcz@...> wrote:?Probably one of safety caps avoiding sparkles when switching on. They can die this way after years and sometimes even cause the fire. Just replace it, it will be OK. Another one can be somewhere in PSU primary circuit, replace it as well.

Daniel Forro

On Aug 5, 2024, at 6:47, Nicole Massey <nyyki@...> wrote:Hello, folks.

So my repair guy tapped on the relay, it thunked, and he plugged it
in and pressed the power button. A capacitor right by the front
power button got hot and let all its smoke out. This can be a couple
of things -- that cap was needing replacement due to age, so it
failed when power got into the system. Or there's something else
wrong that overloaded that cap. There's also the biggest list of possible reasons -- something I don't know about.

Anyone got any ideas?
Nicole

#280

Just to add to what others have said:

?

The most common paper electrolytic caps in older equipment were manufactured by putting an insulating paste between two conductors then applying a small trickle voltage to 'set' the insulating paste.

?

When a piece of electronic equipment is left to sit idle for extended periods of time, the insulating paste can lose the 'set'. Sudden application of power can see a short-circuit through the capacitor, which will quickly heat up, sometimes explode, and sometimes take out part of the circuitry with it. When repairing something after such a failure, you may need to repair burnt circuitry as well.

Other than collateral damage to the circuitry, there is usually nothing ominous about an old electrolytic capacitor exploding.

?

Also, it is sometimes possible to apply a lower voltage and slowly bring an older piece of gear up to full power. This will only be likely to work with older gear: newer things and especially digital devices will usually not function at all below a certain voltage and be fully operational above that voltage.

The best tool for trying this is called a Variac and can be quite expensive. It is possible to construct a "poor man's variac" using a lamp with an incandescent bulb (must be incandescent; LED or CFLs will not work for this).

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A Nonfunctioning 100gx -- Something new