On Feb 5, 7:55 pm, "Arfa Daily" wrote:
"Haaky" wrote in message

ps.com...



Pretty unlikely actually. 7A is not a preferred value so it'll be hard to
come by. You
could always try 8A though to see if it makes a difference.

Graham

Wouldn't i be running a bigger risk putting in an 8A fuse instead of a
7 or a 6.3?

I'de rather the fuse blow instead of a more expensive part.

If it's knocking out a 6.3 amp fuse, and the correct rating that it's
expecting to have in there is a 7 anyway, then trust me, it will have no
problem taking out an 8. I wouldn't necessarily say the same about a 10A,
but the extra couple of microseconds to blow an 8 is not going to damage
anything else. Have we actually established if you have the proper " T "
rated type in there yet, anyway ? If you haven't, then all of this
conjecture about what *might* be wrong is a useless waste of time, as there
may be nothing at all wrong other than an invalid fuse type for that
application ...

Arfa

I have no idea what type of fuse i'm using. There is no making on it
saying it's a "T"
I checked the web site of the company that makes the fuses and i don't
see any "T" listed for that fuse.
It's 250V 6.3A GFE Miniature fuse made by Conquer.

I'm gonna take a strol over to the repair shop and see if they have
any 250V 7A or 8A "T" fuses.

I've looked at Radio Shack or The Source up here in Canada the only 7A
fuses they had were 1-1/4 X 1/4 it didn't look like they would fit
into the fuse holder.

I was thinking maybe, could i replace the fuse holder with a breaker?
I noticed the the manual they talk about a breaker switch and not a
fuse or fuse block.

Haaky wrote:

On Feb 5, 7:55 pm, "Arfa Daily" wrote:
"Haaky" wrote in message

ps.com...



Pretty unlikely actually. 7A is not a preferred value so it'll be hard to
come by. You
could always try 8A though to see if it makes a difference.

Graham

Wouldn't i be running a bigger risk putting in an 8A fuse instead of a
7 or a 6.3?

I'de rather the fuse blow instead of a more expensive part.

If it's knocking out a 6.3 amp fuse, and the correct rating that it's
expecting to have in there is a 7 anyway, then trust me, it will have no
problem taking out an 8. I wouldn't necessarily say the same about a 10A,
but the extra couple of microseconds to blow an 8 is not going to damage
anything else. Have we actually established if you have the proper " T "
rated type in there yet, anyway ? If you haven't, then all of this
conjecture about what *might* be wrong is a useless waste of time, as there
may be nothing at all wrong other than an invalid fuse type for that
application ...

Arfa

I have no idea what type of fuse i'm using. There is no making on it
saying it's a "T"
I checked the web site of the company that makes the fuses and i don't
see any "T" listed for that fuse.
It's 250V 6.3A GFE Miniature fuse made by Conquer.

Google seems to say a GFE type is fast blow.

You need a GDC type ( slow blow ).


I'm gonna take a strol over to the repair shop and see if they have
any 250V 7A or 8A "T" fuses.

I've looked at Radio Shack or The Source up here in Canada the only 7A
fuses they had were 1-1/4 X 1/4 it didn't look like they would fit
into the fuse holder.

I was thinking maybe, could i replace the fuse holder with a breaker?
I noticed the the manual they talk about a breaker switch and not a
fuse or fuse block.

You'll need a 20 mm fuse. like this

http://www.radioshack.com/product/in...tId=2102764&cp

Graham

On Feb 6, 11:17 am, Eeyore
wrote:
Haaky wrote:
On Feb 5, 7:55 pm, "Arfa Daily" wrote:
"Haaky" wrote in message

ups.com...

Pretty unlikely actually. 7A is not a preferred value so it'll be hard to
come by. You
could always try 8A though to see if it makes a difference.

Graham

Wouldn't i be running a bigger risk putting in an 8A fuse instead of a
7 or a 6.3?

I'de rather the fuse blow instead of a more expensive part.

If it's knocking out a 6.3 amp fuse, and the correct rating that it's
expecting to have in there is a 7 anyway, then trust me, it will have no
problem taking out an 8. I wouldn't necessarily say the same about a 10A,
but the extra couple of microseconds to blow an 8 is not going to damage
anything else. Have we actually established if you have the proper " T "
rated type in there yet, anyway ? If you haven't, then all of this
conjecture about what *might* be wrong is a useless waste of time, as there
may be nothing at all wrong other than an invalid fuse type for that
application ...

Arfa

I have no idea what type of fuse i'm using. There is no making on it
saying it's a "T"
I checked the web site of the company that makes the fuses and i don't
see any "T" listed for that fuse.
It's 250V 6.3A GFE Miniature fuse made by Conquer.

Google seems to say a GFE type is fast blow.

You need a GDC type ( slow blow ).

I'm gonna take a strol over to the repair shop and see if they have
any 250V 7A or 8A "T" fuses.

I've looked at Radio Shack or The Source up here in Canada the only 7A
fuses they had were 1-1/4 X 1/4 it didn't look like they would fit
into the fuse holder.

I was thinking maybe, could i replace the fuse holder with a breaker?
I noticed the the manual they talk about a breaker switch and not a
fuse or fuse block.

You'll need a 20 mm fuse. like this

http://www.radioshack.com/product/in...tId=2102764&cp

Graham

Ok i see i'm using a GFE type fuse when i should be using a GDC type
fuse i was gonna ask how to tell the difference.
I almost missed that line above my quote.

So i guess a GFE fuse is just an ordinary run of the mill every day
fuse And a GDC would be a slow blow.

Now are Time Delayed and Slow Blow fuses the same thing or are they
different.

Man you know how much this would cost me if i was to take a course and
my local collage to find this stuff out

I think we narrowed it down to me having to use the proper fuse. Which
obviously i am not using in the amp

I'm surprised this didn't happen along time ago. Maybe because of the
new part that was installed.

On Feb 6, 11:17 am, Eeyore
wrote:
Haaky wrote:
On Feb 5, 7:55 pm, "Arfa Daily" wrote:
"Haaky" wrote in message

ups.com...

Pretty unlikely actually. 7A is not a preferred value so it'll be hard to
come by. You
could always try 8A though to see if it makes a difference.

Graham

Wouldn't i be running a bigger risk putting in an 8A fuse instead of a
7 or a 6.3?

I'de rather the fuse blow instead of a more expensive part.

If it's knocking out a 6.3 amp fuse, and the correct rating that it's
expecting to have in there is a 7 anyway, then trust me, it will have no
problem taking out an 8. I wouldn't necessarily say the same about a 10A,
but the extra couple of microseconds to blow an 8 is not going to damage
anything else. Have we actually established if you have the proper " T "
rated type in there yet, anyway ? If you haven't, then all of this
conjecture about what *might* be wrong is a useless waste of time, as there
may be nothing at all wrong other than an invalid fuse type for that
application ...

Arfa

I have no idea what type of fuse i'm using. There is no making on it
saying it's a "T"
I checked the web site of the company that makes the fuses and i don't
see any "T" listed for that fuse.
It's 250V 6.3A GFE Miniature fuse made by Conquer.

Google seems to say a GFE type is fast blow.

You need a GDC type ( slow blow ).

I'm gonna take a strol over to the repair shop and see if they have
any 250V 7A or 8A "T" fuses.

I've looked at Radio Shack or The Source up here in Canada the only 7A
fuses they had were 1-1/4 X 1/4 it didn't look like they would fit
into the fuse holder.

I was thinking maybe, could i replace the fuse holder with a breaker?
I noticed the the manual they talk about a breaker switch and not a
fuse or fuse block.

You'll need a 20 mm fuse. like this

http://www.radioshack.com/product/in...tId=2102764&cp

Graham

On further inspection of this amp i noticed the Output Transistors are
as follows

2- c2837's as a pair
2- a1186's as a pair
1-a1492 \__ shouldn't these be the same
1-a1186 /
1-c2837 \__ shouldn't these be the same
1-c3856 /

I was just wondering it's probably the design of the amp.
Kind of through me when i took a closer look
I would have thought that each of the last 2 pairs would have been
matching like the first 2 pairs.

Shouldn't the 1 side of the amp be a mirror of the other side. Or is
this because you can switch it to Bridged mono?

Just let me know if you guys are getting tired of all these
questions.....My head is like a sponge now. The more i learn the
more i want to learn.

i uploaded a schematic onto abse it's in Microsoft Office .rtf form i
had to convert it from PDF to be able to print it properly

Here we go again

I just checked the schematics and i don't see any a1492 or c3856
listed on there at all

Haaky wrote:

Eeyore wrote:
Haaky wrote:

I have no idea what type of fuse i'm using. There is no making on it
saying it's a "T"
I checked the web site of the company that makes the fuses and i don't
see any "T" listed for that fuse.
It's 250V 6.3A GFE Miniature fuse made by Conquer.

Google seems to say a GFE type is fast blow.

You need a GDC type ( slow blow ).

I'm gonna take a strol over to the repair shop and see if they have
any 250V 7A or 8A "T" fuses.

I've looked at Radio Shack or The Source up here in Canada the only 7A
fuses they had were 1-1/4 X 1/4 it didn't look like they would fit
into the fuse holder.

I was thinking maybe, could i replace the fuse holder with a breaker?
I noticed the the manual they talk about a breaker switch and not a
fuse or fuse block.

You'll need a 20 mm fuse. like this

http://www.radioshack.com/product/in...tId=2102764&cp

Graham

Ok i see i'm using a GFE type fuse when i should be using a GDC type
fuse i was gonna ask how to tell the difference.
I almost missed that line above my quote.

So i guess a GFE fuse is just an ordinary run of the mill every day
fuse And a GDC would be a slow blow.

Now are Time Delayed and Slow Blow fuses the same thing or are they
different.

They are in principle the same thing but a US 'slo-blo' and a European/International
'T' have slightly different fusing characteristics. Not different enough to worry
about in this case though.


Man you know how much this would cost me if i was to take a course and
my local collage to find this stuff out

LOTS !


I think we narrowed it down to me having to use the proper fuse. Which
obviously i am not using in the amp

I'm surprised this didn't happen along time ago. Maybe because of the
new part that was installed.

What type was it before that part failed though ? It was probably originally the right
type.

Graham

On Feb 6, 5:36 pm, Eeyore
wrote:
Haaky wrote:
Eeyore wrote:
Haaky wrote:

I have no idea what type of fuse i'm using. There is no making on it
saying it's a "T"
I checked the web site of the company that makes the fuses and i don't
see any "T" listed for that fuse.
It's 250V 6.3A GFE Miniature fuse made by Conquer.

Google seems to say a GFE type is fast blow.

You need a GDC type ( slow blow ).

I'm gonna take a strol over to the repair shop and see if they have
any 250V 7A or 8A "T" fuses.

I've looked at Radio Shack or The Source up here in Canada the only 7A
fuses they had were 1-1/4 X 1/4 it didn't look like they would fit
into the fuse holder.

I was thinking maybe, could i replace the fuse holder with a breaker?
I noticed the the manual they talk about a breaker switch and not a
fuse or fuse block.

You'll need a 20 mm fuse. like this

http://www.radioshack.com/product/in...tId=2102764&cp

Graham

Ok i see i'm using a GFE type fuse when i should be using a GDC type
fuse i was gonna ask how to tell the difference.
I almost missed that line above my quote.

So i guess a GFE fuse is just an ordinary run of the mill every day
fuse And a GDC would be a slow blow.

Now are Time Delayed and Slow Blow fuses the same thing or are they
different.

They are in principle the same thing but a US 'slo-blo' and a European/International
'T' have slightly different fusing characteristics. Not different enough to worry
about in this case though.

Man you know how much this would cost me if i was to take a course and
my local collage to find this stuff out

LOTS !

I think we narrowed it down to me having to use the proper fuse. Which
obviously i am not using in the amp

I'm surprised this didn't happen along time ago. Maybe because of the
new part that was installed.

What type was it before that part failed though ? It was probably originally the right
type.

Graham

The fuse that went when all this trouble started was the same type
that i'm replacing 250V 6.3A
No "T" type or slow blow. I never had a fuse go until i had the
problem with the output.

I'm about to turn the amp on right now and see what happens. I'm gonna
check and see if i can get the 7A slow blow fuse from the repair shop
I checked radio shack and they didn't have them in the mini fuses

"Haaky" wrote in message
ps.com...
Here we go again

I just checked the schematics and i don't see any a1492 or c3856
listed on there at all



It would seem that your transistors have been subbed when it was repaired.
This is not uncommon, and I have on occasion done it myself, although where
possible, I prefer to use original types, even down to actually obtaining
them from the equipment manufacturer, rather than a third party general
spares supplier.

Theoretically, the transistors should indeed match on both channels, as your
schematic suggests. Sometimes however, particular types are either difficult
to obtain, or prohibitively expensive. Most repair people will have their
own favourite substitute types to use in cases like this. Usually, these
substitute parts are chosen to be better rated than the types that they are
replacing, so don't cause a problem. In general, the output transistors are
just meaty current carriers, and for the most part, due to the large amounts
of feedback being employed, and automatic bias stabilisation, their exact
characteristics are not that important. Occasionally though, an output
circuit design is critical of such parameters as transistor gain, and
substitute devices just will not work well in it. This usually manifests
itself, however, as symptoms like long-term overheating, and a failure of
the bias circuit to operate correctly. Also, some output stages use
darlington transistors, which of course cannot be substituted with 'normal'
types, and in fact I would not recommend that they be replaced with anything
other than originals.

Without going and looking up the differences between what was originally
fitted, and what is now, I wouldn't like to say for sure whether they are
valid substitute types, but I'm willing to bet that they will probably be
OK, and are not the cause of the problem, as you said previously that when
it is running, it does not overheat, and sounds fine.

Fuse blowing at switch on is not something that you would normally consider
to be output stage related, unless it is a 'hard' fault such as a short
circuit device, in which case, the amp would never be able to work. I still
think that all you need, is to get the correct fuse type in there, and all
will be well. If the type that is in there is indeed a fast blow, as
Graham's research would suggest, then it is not a valid type for that
position, and will blow in just the way that you are seeing. Also, as Graham
says, slo-blo and " T " rated are not quite the same on paper, but to all
intents and purposes for this discussion, they can both be treated as
'equivalent' anti-surge types. Get the right fuse in there, and then come
back to us in a couple of weeks and tell us that it's OK now.

Arfa

Haaky wrote:

Eeyore wrote:
Haaky wrote:
Eeyore wrote:
Haaky wrote:

You'll need a 20 mm fuse. like this

http://www.radioshack.com/product/in...tId=2102764&cp

Graham

Ok i see i'm using a GFE type fuse when i should be using a GDC type
fuse i was gonna ask how to tell the difference.
I almost missed that line above my quote.

So i guess a GFE fuse is just an ordinary run of the mill every day
fuse And a GDC would be a slow blow.

Now are Time Delayed and Slow Blow fuses the same thing or are they
different.

They are in principle the same thing but a US 'slo-blo' and a European/International
'T' have slightly different fusing characteristics. Not different enough to worry
about in this case though.

Man you know how much this would cost me if i was to take a course and
my local collage to find this stuff out

LOTS !

I think we narrowed it down to me having to use the proper fuse. Which
obviously i am not using in the amp

I'm surprised this didn't happen along time ago. Maybe because of the
new part that was installed.

What type was it before that part failed though ? It was probably originally the right
type.

The fuse that went when all this trouble started was the same type
that i'm replacing 250V 6.3A
No "T" type or slow blow. I never had a fuse go until i had the
problem with the output.

You were just lucky I reckon in that case.


I'm about to turn the amp on right now and see what happens. I'm gonna
check and see if i can get the 7A slow blow fuse from the repair shop
I checked radio shack and they didn't have them in the mini fuses

Forget 7 amps, it's a non-preferred value and not ultra-critical anyway.

Just get a 20mm 6.3A slow-blow ( T ) fuse. I gave you a link to Radio Shack's part number
for it earlier if you can't get it anywhere else.
http://www.radioshack.com/product/in...tId=2102764&cp

Graham

Arfa Daily wrote:

Without going and looking up the differences between what was originally
fitted, and what is now, I wouldn't like to say for sure whether they are
valid substitute types, but I'm willing to bet that they will probably be
OK, and are not the cause of the problem, as you said previously that when
it is running, it does not overheat, and sounds fine.

The replacements are slightly higher wattage ( 130W in place of 100W ) but lower
fT ( 20MHz rather than 60MHz ) .

It's conceivable that the replacements may be causing ultrasonic oscillation
/instability. That would tie up with the observed effects.

Graham

"Eeyore" wrote in message
...


Arfa Daily wrote:

Without going and looking up the differences between what was originally
fitted, and what is now, I wouldn't like to say for sure whether they are
valid substitute types, but I'm willing to bet that they will probably be
OK, and are not the cause of the problem, as you said previously that
when
it is running, it does not overheat, and sounds fine.

The replacements are slightly higher wattage ( 130W in place of 100W ) but
lower
fT ( 20MHz rather than 60MHz ) .

It's conceivable that the replacements may be causing ultrasonic
oscillation
/instability. That would tie up with the observed effects.

Graham

Agreed possible. Would depend on how quickly the fuse blows after the on /
off switch is made. I would expect there to be a short delay before a
hooting output built up enough oomph to draw the current necessary to blow a
6 odd amp primary fuse. I got the impression that this fuse was going out
pretty much immediately that the switch was closed, and also without any
signs of distress, which would indicate to me that it was breaking just
through metal fatigue from repeated inrush-surge sagging events. A hooting
output stage would blow it as a result of pulling excess current, which at
the high frequency the instability would be occuring at, the tranny's
inductance would probably try to limit anyway. A fuse which has blown as a
result of an excess downstream current, usually shows as having a melted
middle, with blobs on the ends of the broken wire. I reckon that it will all
be ok with the proper fuse in it.

Arfa

On Feb 6, 6:49 pm, "Arfa Daily" wrote:
"Haaky" wrote in message

ps.com...

Here we go again

I just checked the schematics and i don't see any a1492 or c3856
listed on there at all

It would seem that your transistors have been subbed when it was repaired.
This is not uncommon, and I have on occasion done it myself, although where
possible, I prefer to use original types, even down to actually obtaining
them from the equipment manufacturer, rather than a third party general
spares supplier.

Theoretically, the transistors should indeed match on both channels, as your
schematic suggests. Sometimes however, particular types are either difficult
to obtain, or prohibitively expensive. Most repair people will have their
own favourite substitute types to use in cases like this. Usually, these
substitute parts are chosen to be better rated than the types that they are
replacing, so don't cause a problem. In general, the output transistors are
just meaty current carriers, and for the most part, due to the large amounts
of feedback being employed, and automatic bias stabilisation, their exact
characteristics are not that important. Occasionally though, an output
circuit design is critical of such parameters as transistor gain, and
substitute devices just will not work well in it. This usually manifests
itself, however, as symptoms like long-term overheating, and a failure of
the bias circuit to operate correctly. Also, some output stages use
darlington transistors, which of course cannot be substituted with 'normal'
types, and in fact I would not recommend that they be replaced with anything
other than originals.

Without going and looking up the differences between what was originally
fitted, and what is now, I wouldn't like to say for sure whether they are
valid substitute types, but I'm willing to bet that they will probably be
OK, and are not the cause of the problem, as you said previously that when
it is running, it does not overheat, and sounds fine.

Fuse blowing at switch on is not something that you would normally consider
to be output stage related, unless it is a 'hard' fault such as a short
circuit device, in which case, the amp would never be able to work. I still
think that all you need, is to get the correct fuse type in there, and all
will be well. If the type that is in there is indeed a fast blow, as
Graham's research would suggest, then it is not a valid type for that
position, and will blow in just the way that you are seeing. Also, as Graham
says, slo-blo and " T " rated are not quite the same on paper, but to all
intents and purposes for this discussion, they can both be treated as
'equivalent' anti-surge types. Get the right fuse in there, and then come
back to us in a couple of weeks and tell us that it's OK now.

Arfa

I think you nailed it on the head. It did seem strange to see the
different output trans in there. I'm thinking that because if that
whoever owned the amp before
me must have had it in for repair. Or it might have even come from the
factory that way. Due to shortage of parts.

I'm going to grab the "Proper" fuses for the amp and see how they
work. Right now i believe that is the only problem with the amp.

It's always better to get different points of views. Especially from
people that have more experience in this stuff than me.

Having said that, it's kinda like a blessing in disguise. Cause after
reading all i can read about it and all this info i've been getting i
really want to get into
the electronic repair more. I'm gonna sign up for some courses and the
collage and get into this. I find really fascinating a **** if
something goes wrong i'm the type of person that would rather fix it
myself.

I did that with cars, construction, computers why not take the next
step and get into electronics. I have to admit some of the stuff is a
little over my head. But i'm understanding so much more now. It's so
cool

Thanks for the help guys, you've put my mind at ease and i know where
to come for help in the future

On Feb 7, 12:36 am, Eeyore
wrote:
Haaky wrote:
Eeyore wrote:
Haaky wrote:
Eeyore wrote:
Haaky wrote:

You'll need a 20 mm fuse. like this

http://www.radioshack.com/product/in...tId=2102764&cp

Graham

Ok i see i'm using a GFE type fuse when i should be using a GDC type
fuse i was gonna ask how to tell the difference.
I almost missed that line above my quote.

So i guess a GFE fuse is just an ordinary run of the mill every day
fuse And a GDC would be a slow blow.

Now are Time Delayed and Slow Blow fuses the same thing or are they
different.

They are in principle the same thing but a US 'slo-blo' and a European/International
'T' have slightly different fusing characteristics. Not different enough to worry
about in this case though.

Man you know how much this would cost me if i was to take a course and
my local collage to find this stuff out

LOTS !

I think we narrowed it down to me having to use the proper fuse. Which
obviously i am not using in the amp

I'm surprised this didn't happen along time ago. Maybe because of the
new part that was installed.

What type was it before that part failed though ? It was probably originally the right
type.

The fuse that went when all this trouble started was the same type
that i'm replacing 250V 6.3A
No "T" type or slow blow. I never had a fuse go until i had the
problem with the output.

You were just lucky I reckon in that case.

I'm about to turn the amp on right now and see what happens. I'm gonna
check and see if i can get the 7A slow blow fuse from the repair shop
I checked radio shack and they didn't have them in the mini fuses

Forget 7 amps, it's a non-preferred value and not ultra-critical anyway.

Just get a 20mm 6.3A slow-blow ( T ) fuse. I gave you a link to Radio Shack's part number
for it earlier if you can't get it anywhere else.
http://www.radioshack.com/product/in...tId=2102764&cp

Graham

Thanks bud for all the info. Exactly what i'm gonna do. I'm glad we
got it narrowed down. I believe that's all the problem is now.

On Feb 7, 10:46 am, Meat Plow wrote:
On Wed, 07 Feb 2007 07:22:53 -0800, Haaky Has Frothed:

[SNIP]

I think you nailed it on the head. It did seem strange to see the
different output trans in there. I'm thinking that because if that
whoever owned the amp before
me must have had it in for repair. Or it might have even come from the
factory that way. Due to shortage of parts.

There are always tell-tale marks when components have been de/resoldered.

--
Pierre Salinger Memorial Hook, Line & Sinker, June 2004

COOSN-266-06-25794

I'm gonna check under the circuit board just out of curiosity.

"Meat Plow" wrote in message
news
On Wed, 07 Feb 2007 07:22:53 -0800, Haaky Has Frothed:

[SNIP]
I think you nailed it on the head. It did seem strange to see the
different output trans in there. I'm thinking that because if that
whoever owned the amp before
me must have had it in for repair. Or it might have even come from the
factory that way. Due to shortage of parts.

There are always tell-tale marks when components have been de/resoldered.


My old apprentice mentor many many years back, told me that the only way you
should be able to tell that a component has been replaced, is if the
soldering is *better* than the manufacturers original ! A good maxim I
think, and one that has stuck by me for my whole life in the business. I
never use too little solder on a joint, nor too much, and always clean off
the flux residue.

Arfa

On Feb 7, 8:54 pm, "Arfa Daily" wrote:
"Meat Plow" wrote in message

news
On Wed, 07 Feb 2007 07:22:53 -0800, Haaky Has Frothed:

[SNIP]
I think you nailed it on the head. It did seem strange to see the
different output trans in there. I'm thinking that because if that
whoever owned the amp before
me must have had it in for repair. Or it might have even come from the
factory that way. Due to shortage of parts.

There are always tell-tale marks when components have been de/resoldered.

My old apprentice mentor many many years back, told me that the only way you
should be able to tell that a component has been replaced, is if the
soldering is *better* than the manufacturers original ! A good maxim I
think, and one that has stuck by me for my whole life in the business. I
never use too little solder on a joint, nor too much, and always clean off
the flux residue.

Arfa

I like that.

"Meat Plow" wrote in message
news
On Thu, 08 Feb 2007 01:54:22 +0000, Arfa Daily Has Frothed:


"Meat Plow" wrote in message
news
On Wed, 07 Feb 2007 07:22:53 -0800, Haaky Has Frothed:

[SNIP]
I think you nailed it on the head. It did seem strange to see the
different output trans in there. I'm thinking that because if that
whoever owned the amp before
me must have had it in for repair. Or it might have even come from the
factory that way. Due to shortage of parts.

There are always tell-tale marks when components have been
de/resoldered.


My old apprentice mentor many many years back, told me that the only way
you
should be able to tell that a component has been replaced, is if the
soldering is *better* than the manufacturers original ! A good maxim I
think, and one that has stuck by me for my whole life in the business. I
never use too little solder on a joint, nor too much, and always clean
off
the flux residue.

Arfa

As do I but I've seen some real hack jobs in my days.

I sometimes wonder how some of the work that I see has lasted as long as it
has. I can't believe that anyone can have made such scruffy-looking, and
sometimes even mechanically and electrically poor joints, and been satisfied
to declare the job " a good 'un ", and send it on its way !! I
contract-repair large quantities of a power driver board that comes from a
particular drinks vending machine. I took this work from another repair
outfit, because the drinks machine suppliers, were not happy with the long
term reliability that they were getting on the repairs. I still see ones
that he repaired a couple of years ago, coming back now. Electrically, the
repairs were OK, but you have never seen such scruffy work in all your life.
It looks as though the joints were made with a poker heated in the fire,
plumber's solder, and paste flux ... Often, link print between two adjacent
components, is missing, and the link has had to be made by bending over the
leg on the replaced component. It's criminal that such poor quality work
occurs, but more worryingly, if people such as this are carrying out
electronic repair work, are there similarly "qualified" people carrying out
work on your car ... ?

Arfa
--
Pierre Salinger Memorial Hook, Line & Sinker, June 2004

COOSN-266-06-25794

"Meat Plow" wrote in message
news
On Thu, 08 Feb 2007 10:10:52 +0000, Arfa Daily Has Frothed:


"Meat Plow" wrote in message
news
On Thu, 08 Feb 2007 01:54:22 +0000, Arfa Daily Has Frothed:


"Meat Plow" wrote in message
news On Wed, 07 Feb 2007 07:22:53 -0800, Haaky Has Frothed:

[SNIP]
I think you nailed it on the head. It did seem strange to see the
different output trans in there. I'm thinking that because if that
whoever owned the amp before
me must have had it in for repair. Or it might have even come from
the
factory that way. Due to shortage of parts.

There are always tell-tale marks when components have been
de/resoldered.


My old apprentice mentor many many years back, told me that the only
way
you
should be able to tell that a component has been replaced, is if the
soldering is *better* than the manufacturers original ! A good maxim I
think, and one that has stuck by me for my whole life in the business.
I
never use too little solder on a joint, nor too much, and always clean
off
the flux residue.

Arfa

As do I but I've seen some real hack jobs in my days.

I sometimes wonder how some of the work that I see has lasted as long as
it
has. I can't believe that anyone can have made such scruffy-looking, and
sometimes even mechanically and electrically poor joints, and been
satisfied
to declare the job " a good 'un ", and send it on its way !! I
contract-repair large quantities of a power driver board that comes from
a
particular drinks vending machine. I took this work from another repair
outfit, because the drinks machine suppliers, were not happy with the
long
term reliability that they were getting on the repairs. I still see ones
that he repaired a couple of years ago, coming back now. Electrically,
the
repairs were OK, but you have never seen such scruffy work in all your
life.
It looks as though the joints were made with a poker heated in the fire,
plumber's solder, and paste flux ... Often, link print between two
adjacent
components, is missing, and the link has had to be made by bending over
the
leg on the replaced component. It's criminal that such poor quality work
occurs, but more worryingly, if people such as this are carrying out
electronic repair work, are there similarly "qualified" people carrying
out
work on your car ... ?

Arfa

LOL you and I do think alike in this respect at least. Back in the hay-day
of Citizen Band Radio in the US (late 70's)I worked with gentleman who
taught me a lot about the trade. We worked on a bunch of CB radios back
then. Many were from professional truck drivers some driving 80+ kilos and
over for our services. Many of these radios received emergency repairs
from truck stop chop shops which of course didn't last a week. I can
remember removing the cases and shaking my head in disgust at how
butchered some of these radios were. On the other hand when I started with
a company in the mid 80's doing major manufacturer warranty, all I worked
on was returns to large department stores and specialty electronics
stores.
My specialty and training was vcr and mobile audio working on virgin
units.
I took much pride and still do in my soldering techniques along with other
things like wire dressings and the likes.


There's just not many of us left, I fear. One by one, we're all getting old
enough to retire, and there's just not the youth coming into the repair
business to train up to follow on from us. I too worked on what was then
illegal CBs here in the UK in the 70's, and then on the legal variety after
the implementation of the " 27 / 81 " legislation that made it so. The
illegal U.S. models used to be smuggled into the country from the continent,
inside frozen meat carcasses. Happy days putting in extra bands, roger
beeps, five-tones, sel calls, "K" beeps, FM conversions, splits and half
watt conversions. Lots of people used to do those just by sticking a bloody
great resistor in series with the feed to the PA, but it used to cause no
end of modulation compression problems on AM, so I used to do them with a
transistor and pot, which worked a lot nicer, and allowed exactly half a
watt to be set. Do you remember those " disguise " antennas that people used
to fit to cars. It was like a normal telescopic car antenna of the era, but
about twice as fat. People used to think that they were really invisible
with one of those, and a little Jaws II in the glove box, but I used to take
great delight in calling them with " Eyeball the breaker with the disguise
antenna !! " I had a pair of DV27's whipping about on the back of my car.
Looked like a fairground dodgem car ... Happy days, sadly long gone.

Arfa

please Haaic i need the schematics for the GX-300 if u can email me
i will thank you a lot


--
bananas
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bananas wrote:

please Haaic i need the schematics for the GX-300 if u can email me
i will thank you a lot

You have another broken one ?

Graham

Thanks i really apreciate your help, my problem i think was caused
because an excesive input signal, i connected the cpu output directly
with the input of the amp, so always was working with constant cliping
in 8ohms, the fuse blows and when i open the amp the input phase was
carbonized, so i change it for a new one with the seller, now i use a
mixer but i encounter some problems, the fuse still blows, i had
constructed a gx-300 clone with the exact components and works fine,
but i still have the fuse problem in the clone.


--
bananas
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