My Christmas present to the children was a Commodore 64.

I picked it up a couple of months ago, and ran it for several hours to
test it; it was all fine.

On Christmas Eve I tested it again; after a few minutes it would start
throwing junk all over the display and then lock up, and I realised that
the difference was the house at room temperature where it crashed, and
the much cooler garage where it wouldn't.

We've repaired it now (mostly), by resoldering many of the pins on the
PCB where the solder seemed to have developed holes. I've never noticed
this phenomenon before, even in much older equipment. I assume that it
wasn't like that after manufacture.

What causes it?

Presumably, a 30-year-old computer would have had proper lead solder,
not this tin-whiskery lead-free stuff.

Actually it can't have been the soldering alone that fixed it because it
continued to crash; I also used a hot air gun to try to identify the
component that was failing after warming - I only once managed to get
that to trigger the fault, but since then, it hasn't crashed again.

So the crashing is fixed, but the next thing to tackle is the sound
output, which is barely audible.

Anyway, the children have been happily playing The Hobbit and Attack of
the Mutant Camels from tapes that have been sitting in boxes for nearly
three decades, which isn't bad going.

Daniele

On Dec 27, 10:13*pm,
(D.M. Procida) wrote:
My Christmas present to the children was a Commodore 64.

I picked it up a couple of months ago, and ran it for several hours to
test it; it was all fine.

On Christmas Eve I tested it again; after a few minutes it would start
throwing junk all over the display and then lock up, and I realised that
the difference was the house at room temperature where it crashed, and
the much cooler garage where it wouldn't.

We've repaired it now (mostly), by resoldering many of the pins on the
PCB where the solder seemed to have developed holes. I've never noticed
this phenomenon before, even in much older equipment. I assume that it
wasn't like that after manufacture.

What causes it?

Presumably, a 30-year-old computer would have had proper lead solder,
not this tin-whiskery lead-free stuff.

Actually it can't have been the soldering alone that fixed it because it
continued to crash; I also used a hot air gun to try to identify the
component that was failing after warming - I only once managed to get
that to trigger the fault, but since then, it hasn't crashed again.

So the crashing is fixed, but the next thing to tackle is the sound
output, which is barely audible.

Anyway, the children have been happily playing The Hobbit and Attack of
the Mutant Camels from tapes that have been sitting in boxes for nearly
three decades, which isn't bad going.

Daniele

I've occasionally seen examples of other products from that era where
teh soldering was dire, but somehow it worked. Over time the solder
surface oxidises, then contact is no longer good and it fails. Cause:
substandard soldering.


NT

On Tue, 27 Dec 2011 22:13:31 +0000,
(D.M. Procida) wrote:

My Christmas present to the children was a Commodore 64.

I picked it up a couple of months ago, and ran it for several hours to
test it; it was all fine.

On Christmas Eve I tested it again; after a few minutes it would start
throwing junk all over the display and then lock up, and I realised that
the difference was the house at room temperature where it crashed, and
the much cooler garage where it wouldn't.

We've repaired it now (mostly), by resoldering many of the pins on the
PCB where the solder seemed to have developed holes. I've never noticed
this phenomenon before, even in much older equipment. I assume that it
wasn't like that after manufacture.

What causes it?

Presumably, a 30-year-old computer would have had proper lead solder,
not this tin-whiskery lead-free stuff.

Actually it can't have been the soldering alone that fixed it because it
continued to crash; I also used a hot air gun to try to identify the
component that was failing after warming - I only once managed to get
that to trigger the fault, but since then, it hasn't crashed again.

So the crashing is fixed, but the next thing to tackle is the sound
output, which is barely audible.

Anyway, the children have been happily playing The Hobbit and Attack of
the Mutant Camels from tapes that have been sitting in boxes for nearly
three decades, which isn't bad going.

Daniele


Fault finding is probably better assisted by a can of Freezer Spray
from the local Maplins or equivalent.

The solder rot is probably extant because the OEM used solder with a
highly active or acid flux and lousy cleaning (if the board was
cleaned at all) to overcome oxidation of plating on cheap and nasty
PCBs and the terminations of cheap and nasty components to increase
the yield but at the expense of medium to long term reliability. (I
opened up a Sinclair ZX Spectrum once, it looked like a rat had
cr@pped the solder onto the board.)

Reflow the joints with some good honest 60/40 Lead based solder (still
legal for repairs) and a decent temperature controlled soldering iron.
Clean the reflowed joints with Isopropyl Alcohol - if you can get hold
of it - and a stiff brush followed by de-ionised water. Ensure the
board is completely dry before re-applying power.

Regards
JonH

p.s. If you look diligently on the web, you should be able to find US
military handbook MIL-HDBK-2000 (Previously MIL-STD-2000 and WS-6536)
which goes into much more detail and is in the public domain. It's
successors, the IPC 6100 series of workmanship standards are ruinously
expensive.

"NT" wrote in message
...
On Dec 27, 10:13 pm,
(D.M. Procida) wrote:
My Christmas present to the children was a Commodore 64.

I picked it up a couple of months ago, and ran it for several hours to
test it; it was all fine.

On Christmas Eve I tested it again; after a few minutes it would start
throwing junk all over the display and then lock up, and I realised that
the difference was the house at room temperature where it crashed, and
the much cooler garage where it wouldn't.

We've repaired it now (mostly), by resoldering many of the pins on the
PCB where the solder seemed to have developed holes. I've never noticed
this phenomenon before, even in much older equipment. I assume that it
wasn't like that after manufacture.

What causes it?

Presumably, a 30-year-old computer would have had proper lead solder,
not this tin-whiskery lead-free stuff.

Actually it can't have been the soldering alone that fixed it because it
continued to crash; I also used a hot air gun to try to identify the
component that was failing after warming - I only once managed to get
that to trigger the fault, but since then, it hasn't crashed again.

So the crashing is fixed, but the next thing to tackle is the sound
output, which is barely audible.

Anyway, the children have been happily playing The Hobbit and Attack of
the Mutant Camels from tapes that have been sitting in boxes for nearly
three decades, which isn't bad going.

Daniele

I've occasionally seen examples of other products from that era where
teh soldering was dire, but somehow it worked. Over time the solder
surface oxidises, then contact is no longer good and it fails. Cause:
substandard soldering.


We used to get a lot of Apricot F1's with joints like this on the power
conns -
http://community.moertel.com/~thor/b...blem-close.jpg

wrote:

Reflow the joints with some good honest 60/40 Lead based solder (still
legal for repairs) and a decent temperature controlled soldering iron.

Is there any problem mixing lead and lead-free solder?

Daniele

Leaded solder usually fails where subjected to heat cycling and or
vibration. Favourite example would be line output transformer in a CRT TV
etc where it gets both.

I've got a home made transistor portable radio - which suffers near zero
from both - still working fine after 50 years.

--
*It doesn't take a genius to spot a goat in a flock of sheep *

Dave Plowman London SW
To e-mail, change noise into sound.

In article
,
D.M. Procida wrote:
Reflow the joints with some good honest 60/40 Lead based solder (still
legal for repairs) and a decent temperature controlled soldering iron.

Is there any problem mixing lead and lead-free solder?

Using leaded to repair a lead free joint is fine. Only a madman would do
it the opposite way round.

--
*Change is inevitable ... except from vending machines *

Dave Plowman London SW
To e-mail, change noise into sound.

On 27 Dec,
Huge wrote:

On 2011-12-27, wrote:

Clean the reflowed joints with Isopropyl Alcohol - if you can get hold
of it

Readily available on eBay. To my surprise.

I got my last lot from CPC about a year ago.


--
B Thumbs
Change lycos to yahoo to reply

On Tue, 27 Dec 2011 14:53:41 -0800, NT wrote:
I've occasionally seen examples of other products from that era where
teh soldering was dire, but somehow it worked. Over time the solder
surface oxidises, then contact is no longer good and it fails. Cause:
substandard soldering.

TVs seem to be about the worst culprits IME. I've found soldering to
typically be good on vintage 'home' computers - less so on the games
consoles of the era.

cheers

Jules

D.M. Procida wrote:
wrote:

Reflow the joints with some good honest 60/40 Lead based solder (still
legal for repairs) and a decent temperature controlled soldering iron.

Is there any problem mixing lead and lead-free solder?

Not really.

Daniele

In message , Huge
writes
On 2011-12-27, wrote:

Clean the reflowed joints with Isopropyl Alcohol - if you can get hold
of it

Readily available on eBay. To my surprise.

Why so ?

Its been discussed to death in the past - about £6 /litre from CPC for
example


--
geoff

On Dec 27, 10:13*pm,
(D.M. Procida) wrote:
My Christmas present to the children was a Commodore 64.

I picked it up a couple of months ago, and ran it for several hours to
test it; it was all fine.

On Christmas Eve I tested it again; after a few minutes it would start
throwing junk all over the display and then lock up, and I realised that
the difference was the house at room temperature where it crashed, and
the much cooler garage where it wouldn't.

We've repaired it now (mostly), by resoldering many of the pins on the
PCB where the solder seemed to have developed holes. I've never noticed
this phenomenon before, even in much older equipment. I assume that it
wasn't like that after manufacture.

What causes it?

An inclusion of grit in the joint which is the seed for oxidation to
occur.


Presumably, a 30-year-old computer would have had proper lead solder,
not this tin-whiskery lead-free stuff.

Probably.

Actually it can't have been the soldering alone that fixed it because it
continued to crash; I also used a hot air gun to try to identify the
component that was failing after warming - I only once managed to get
that to trigger the fault, but since then, it hasn't crashed again.

So the crashing is fixed, but the next thing to tackle is the sound
output, which is barely audible.

Anyway, the children have been happily playing The Hobbit and Attack of
the Mutant Camels from tapes that have been sitting in boxes for nearly
three decades, which isn't bad going.

Daniele

"Huge" wrote in message
...
On 2011-12-27, wrote:

Clean the reflowed joints with Isopropyl Alcohol - if you can get hold
of it

Readily available on eBay. To my surprise.

--

Not really a surprise as you can often purchase it from you r local pharmacy
like I do. Reminds me, I have juist run out.....
Jim G

On Tue, 27 Dec 2011 23:28:46 +0000,
(D.M. Procida) wrote:

wrote:

Reflow the joints with some good honest 60/40 Lead based solder (still
legal for repairs) and a decent temperature controlled soldering iron.

Is there any problem mixing lead and lead-free solder?

Daniele


Depends on the alloy. Some of the Lead-free solders currently
available contain high quantities of Zinc. While they flow and melt
like 60/40, they are prone to corrosion.

Other mixes don't perform well at low temperatures (especially high
Tin alloys) or under vibration. Probably OK for most domestic
applications, not good at all for aerospace.

Your equipment will almost certainly have been made using Tin/Lead
solder.

Regards
JonH

Yes indeed. Well solder joints get dry due to oxide forming on the component
wires where the solder did not take correctly to start with.

The effect used to hit pcbs before plated through holes where rivets used to
do that job and of course under a high powered magnifier you could see the
furryness forcing its way under the solder.
Another thing I encountered recently via a sighted person was that some of
the chips of that era had poorly plated pins and in some cases they actually
oxidised completely through causing all sorts of problems. OK if its a z80
or 6502 etc, processor there are still some made but some of the custom
chips like in the 64 you are stuffed.
With regard to sound. Are you using a modern analogue tv to get the sound
out?
Most of these are digitally tuned and the modulators in these computers
tend to drift. In the old sets the afc followed the drift, but not the newer
models. Often, its better to wire up a monitor lead and get the sound out as
audio.
some of these older machines have psu faults. The ripples on the picture or
hum on sound make it rather obvious that the capacitors have dried out. You
can get new ones fairly cheaply of course.
Brian

--
Brian Gaff -
Note:- In order to reduce spam, any email without 'Brian Gaff'
in the display name may be lost.
Blind user, so no pictures please!
"D.M. Procida" wrote in
message
...
My Christmas present to the children was a Commodore 64.

I picked it up a couple of months ago, and ran it for several hours to
test it; it was all fine.

On Christmas Eve I tested it again; after a few minutes it would start
throwing junk all over the display and then lock up, and I realised that
the difference was the house at room temperature where it crashed, and
the much cooler garage where it wouldn't.

We've repaired it now (mostly), by resoldering many of the pins on the
PCB where the solder seemed to have developed holes. I've never noticed
this phenomenon before, even in much older equipment. I assume that it
wasn't like that after manufacture.

What causes it?

Presumably, a 30-year-old computer would have had proper lead solder,
not this tin-whiskery lead-free stuff.

Actually it can't have been the soldering alone that fixed it because it
continued to crash; I also used a hot air gun to try to identify the
component that was failing after warming - I only once managed to get
that to trigger the fault, but since then, it hasn't crashed again.

So the crashing is fixed, but the next thing to tackle is the sound
output, which is barely audible.

Anyway, the children have been happily playing The Hobbit and Attack of
the Mutant Camels from tapes that have been sitting in boxes for nearly
three decades, which isn't bad going.

Daniele

So what is in the lead free solder to replace the lead, and can we look
forward in a few years to learn this new substance is more dangerous than
the lead...
Brian

--
Brian Gaff -
Note:- In order to reduce spam, any email without 'Brian Gaff'
in the display name may be lost.
Blind user, so no pictures please!
"Dave Plowman (News)" wrote in message
...
In article
,
D.M. Procida wrote:
Reflow the joints with some good honest 60/40 Lead based solder (still
legal for repairs) and a decent temperature controlled soldering iron.

Is there any problem mixing lead and lead-free solder?

Using leaded to repair a lead free joint is fine. Only a madman would do
it the opposite way round.

--
*Change is inevitable ... except from vending machines *

Dave Plowman London SW
To e-mail, change noise into sound.

Brian Gaff wrote:

Most of these are digitally tuned and the modulators in these computers
tend to drift. In the old sets the afc followed the drift, but not the newer
models. Often, its better to wire up a monitor lead and get the sound out as
audio.

No, it's not the modulator - I get it on the audio out too. And I don't
think it's the amplifier either, as a tone from a signal generator on
the right pin of the sound chip socket comes through very clearly.

Daniele

Brian Gaff wrote:
So what is in the lead free solder to replace the lead, and can we look
forward in a few years to learn this new substance is more dangerous than
the lead...

Tin, 3.5 percent silver and 0.7 percent copper (Roughly), with some
having a minute amount of zinc to reduce the melting point.

The main known problems are the mechanical strength and formation of
whiskers in hand work if temperature isn't correctly controlled. The
melting point is also about 20 degrees higher than Tin lead solder.

--
Tciao for Now!

John.

On Wed, 28 Dec 2011 08:51:49 +0000, wrote:

On Tue, 27 Dec 2011 23:28:46 +0000,
(D.M. Procida) wrote:

wrote:

Reflow the joints with some good honest 60/40 Lead based solder (still
legal for repairs) and a decent temperature controlled soldering iron.

Is there any problem mixing lead and lead-free solder?

Daniele


Depends on the alloy. Some of the Lead-free solders currently
available contain high quantities of Zinc. While they flow and melt
like 60/40, they are prone to corrosion.

Other mixes don't perform well at low temperatures (especially high
Tin alloys) or under vibration. Probably OK for most domestic
applications, not good at all for aerospace.

Just curious - what type of solder (if any) IS used in the aerospace
industry these days?

I think I've got enough tin/lead (grade K) to see me out anyway :-)

--
Frank Erskine

Frank Erskine wrote:

On Wed, 28 Dec 2011 08:51:49 +0000, wrote:

On Tue, 27 Dec 2011 23:28:46 +0000,
(D.M. Procida) wrote:

wrote:

Reflow the joints with some good honest 60/40 Lead based solder (still
legal for repairs) and a decent temperature controlled soldering iron.

Is there any problem mixing lead and lead-free solder?

Daniele


Depends on the alloy. Some of the Lead-free solders currently
available contain high quantities of Zinc. While they flow and melt
like 60/40, they are prone to corrosion.

Other mixes don't perform well at low temperatures (especially high
Tin alloys) or under vibration. Probably OK for most domestic
applications, not good at all for aerospace.

Just curious - what type of solder (if any) IS used in the aerospace
industry these days?

I think I've got enough tin/lead (grade K) to see me out anyway :-)


Leaded I would imagine, seeing as the automotive industry is exempted from
the lead free requirement, so moreso the aerospace industry.

--
Tim Watts

On Wed, 28 Dec 2011 11:46:37 +0000, Tim Watts
wrote:

Frank Erskine wrote:

On Wed, 28 Dec 2011 08:51:49 +0000, wrote:

On Tue, 27 Dec 2011 23:28:46 +0000,
(D.M. Procida) wrote:

wrote:

Reflow the joints with some good honest 60/40 Lead based solder (still
legal for repairs) and a decent temperature controlled soldering iron.

Is there any problem mixing lead and lead-free solder?

Daniele


Depends on the alloy. Some of the Lead-free solders currently
available contain high quantities of Zinc. While they flow and melt
like 60/40, they are prone to corrosion.

Other mixes don't perform well at low temperatures (especially high
Tin alloys) or under vibration. Probably OK for most domestic
applications, not good at all for aerospace.

Just curious - what type of solder (if any) IS used in the aerospace
industry these days?

I think I've got enough tin/lead (grade K) to see me out anyway :-)


Leaded I would imagine, seeing as the automotive industry is exempted from
the lead free requirement, so moreso the aerospace industry.

Yes, and for products involved in the safety of the realm.

Regards
JonH

Tim Watts wrote:

Leaded I would imagine, seeing as the automotive industry is exempted from
the lead free requirement, so moreso the aerospace industry.

What exactly was the problem with lead solder? Were children eating it
or something?

Daniele

D.M. Procida wrote:
Tim Watts wrote:

Leaded I would imagine, seeing as the automotive industry is exempted from
the lead free requirement, so moreso the aerospace industry.

What exactly was the problem with lead solder? Were children eating it
or something?

The Powers That Be decided that if electronics stuff containing lead was
disposed by dumping it into landfill, the lead would leach out into the
water supply or if it was burnt, the lead would be carried in the flue
gases and spread itself all over the landscape.

--
Tciao for Now!

John.

John Williamson wrote:

D.M. Procida wrote:
Tim Watts wrote:

Leaded I would imagine, seeing as the automotive industry is exempted from
the lead free requirement, so moreso the aerospace industry.

What exactly was the problem with lead solder? Were children eating it
or something?

The Powers That Be decided that if electronics stuff containing lead was
disposed by dumping it into landfill, the lead would leach out into the
water supply or if it was burnt, the lead would be carried in the flue
gases and spread itself all over the landscape.

.... whereas it's really great for the environment for our society to
dispose of mountains of prematurely-deceased tin-whiskered electronic
junk.

Daniele

D.M. Procida wrote:
John Williamson wrote:

D.M. Procida wrote:
Tim Watts wrote:

Leaded I would imagine, seeing as the automotive industry is exempted from
the lead free requirement, so moreso the aerospace industry.
What exactly was the problem with lead solder? Were children eating it
or something?

The Powers That Be decided that if electronics stuff containing lead was
disposed by dumping it into landfill, the lead would leach out into the
water supply or if it was burnt, the lead would be carried in the flue
gases and spread itself all over the landscape.

... whereas it's really great for the environment for our society to
dispose of mountains of prematurely-deceased tin-whiskered electronic
junk.

You noticed the shortcomings, then.


--
Tciao for Now!

John.

On Wed, 28 Dec 2011 09:27:55 +0000, Brian Gaff wrote:
Another thing I encountered recently via a sighted person was that some
of
the chips of that era had poorly plated pins and in some cases they
actually oxidised completely through causing all sorts of problems.

Yes, I've seen that too, particularly on 1970s and very early 1980's
machines. In some cases they seem to rot from the inside-out, so visually
the pins look OK but electrically and mechanically they're very weak (I
remember needing to replace about half the ICs in one particular machine)

if its a z80 or 6502 etc, processor there are still some made but some
of the custom chips like in the 64 you are stuffed.

I've fixed a few Commodore PETs over the years, but didn't mess with the
C64 so much - although I remember working on SX64s (which IIRC are much
the same guts) and there was one particular custom IC which had a
reputation for failing for no good reason.

With regard to sound. Are you using a modern analogue tv to get the
sound out?
Most of these are digitally tuned and the modulators in these computers
tend to drift.

Picture, too; my ZX80 was a right ******* when it came to getting any
form of remotely modern TV to lock on to its signal.

some of these older machines have psu faults. The ripples on the
picture or
hum on sound make it rather obvious that the capacitors have dried out.

In some cases, yes. The vast majority of faults I've found to be
mechanical in nature - keyboard switches, connectors, IC sockets etc.

Occasionally a reset circuit will die, and memory faults are reasonably
common.

I've lost count of how many times I've seen one of the noise surpession
capacitors on the mains side of a PSU let go with clouds of smoke,
though.

cheers

Jules

In article ,
says...

On Wed, 28 Dec 2011 09:27:55 +0000, Brian Gaff wrote:
Another thing I encountered recently via a sighted person was that some
of
the chips of that era had poorly plated pins and in some cases they
actually oxidised completely through causing all sorts of problems.

Yes, I've seen that too, particularly on 1970s and very early 1980's
machines. In some cases they seem to rot from the inside-out, so visually
the pins look OK but electrically and mechanically they're very weak (I
remember needing to replace about half the ICs in one particular machine)


Another inside-out phenomenon - and a dire warning of what to expect in
the future with all the electronics built with lead free solder - was
the problem exhibited by Mullard/Philips AF11n range of transistors.

These had a fourth wire connected to the metal can for earthing
purposes. Why, I don't know, because the previous OC4n range were in an
unscreened glass enclosure and the later AF12n range didn't have an
earth wire.

However, the problem was that the AF11n range were built in tin plated
metal cans. The tin grows whiskers - literally hundreds of the things -
until, eventually, one of them contacts the transistor assembly itself
and stops it dead.

An excellent set of slides from a NASA investigation of the problem can
be seen at:

http://www.vintage-radio.info/whiske...usse-Whiskers%
20Inside%20AF114%20Transistors.pps

or http://tinyurl.com/cgfbmfd

--

Terry

Jules Richardson wrote:
On Wed, 28 Dec 2011 09:27:55 +0000, Brian Gaff wrote:
Another thing I encountered recently via a sighted person was that some
of
the chips of that era had poorly plated pins and in some cases they
actually oxidised completely through causing all sorts of problems.

Yes, I've seen that too, particularly on 1970s and very early 1980's
machines. In some cases they seem to rot from the inside-out, so visually
the pins look OK but electrically and mechanically they're very weak (I
remember needing to replace about half the ICs in one particular machine)

if its a z80 or 6502 etc, processor there are still some made but some
of the custom chips like in the 64 you are stuffed.

I've fixed a few Commodore PETs over the years, but didn't mess with the
C64 so much - although I remember working on SX64s (which IIRC are much
the same guts) and there was one particular custom IC which had a
reputation for failing for no good reason.

With regard to sound. Are you using a modern analogue tv to get the
sound out?
Most of these are digitally tuned and the modulators in these computers
tend to drift.

Picture, too; my ZX80 was a right ******* when it came to getting any
form of remotely modern TV to lock on to its signal.

some of these older machines have psu faults. The ripples on the
picture or
hum on sound make it rather obvious that the capacitors have dried out.

In some cases, yes. The vast majority of faults I've found to be
mechanical in nature - keyboard switches, connectors, IC sockets etc.

Occasionally a reset circuit will die, and memory faults are reasonably
common.

I've lost count of how many times I've seen one of the noise surpession
capacitors on the mains side of a PSU let go with clouds of smoke,
though.

cheers

Jules
Isn't it better to get one of those emulator things and run the games
under that?

a pentium running a Z80 simulator is still faster than a z-80 :-)

On 28/12/2011 11:37, Frank Erskine wrote:
On Wed, 28 Dec 2011 08:51:49 +0000, wrote:

On Tue, 27 Dec 2011 23:28:46 +0000,
(D.M. Procida) wrote:

wrote:

Reflow the joints with some good honest 60/40 Lead based solder (still
legal for repairs) and a decent temperature controlled soldering iron.

Is there any problem mixing lead and lead-free solder?

Daniele


Depends on the alloy. Some of the Lead-free solders currently
available contain high quantities of Zinc. While they flow and melt
like 60/40, they are prone to corrosion.

Other mixes don't perform well at low temperatures (especially high
Tin alloys) or under vibration. Probably OK for most domestic
applications, not good at all for aerospace.

Just curious - what type of solder (if any) IS used in the aerospace
industry these days?

Quite often lead free in Europe, although it can be tricky on military
stuff where you have US manufactured primary parts (or second source -
as is usually a requirement) - since they will often come pre-tinned
with leaded solder.

I think I've got enough tin/lead (grade K) to see me out anyway :-)

Its still readily available anyway since its needed for repair work on
existing equipment. CPC do it.


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On 28/12/2011 09:59, D.M. Procida wrote:
Brian wrote:

Most of these are digitally tuned and the modulators in these computers
tend to drift. In the old sets the afc followed the drift, but not the newer
models. Often, its better to wire up a monitor lead and get the sound out as
audio.

No, it's not the modulator - I get it on the audio out too. And I don't
think it's the amplifier either, as a tone from a signal generator on
the right pin of the sound chip socket comes through very clearly.

Dead 5481 SID chip possibly... (plenty on eBay, for a price!)


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

The Natural Philosopher wrote:

Isn't it better to get one of those emulator things and run the games
under that?

a pentium running a Z80 simulator is still faster than a z-80 :-)

It depends what you want it for. The real thing seems more fun to me.

Daniele

Yes the Comode actually runs a derivitive of the 6502 with a number of
custom chips for sound and graphics.
They were fun and even had pretty good built in basic, though I preferred
the Sinclair for that.
I have an Atari here and wondered if it might still work. Not for me, but
if anyone wants it to try, they are welcome to it as it has all the bits,
disc drive, tape deck and printer interface. 8 bit with some carts and
software but of course not run up for a loooong time so may not work. the
leads are custom pludgged though and the psus are here but which is which?
800 xl.
Brian

--
Brian Gaff....Note, this account does not accept Bcc: email.
graphics are great, but the blind can't hear them
Email:
__________________________________________________ __________________________________________________ __________


"D.M. Procida" wrote in
message
...
The Natural Philosopher wrote:

Isn't it better to get one of those emulator things and run the games
under that?

a pentium running a Z80 simulator is still faster than a z-80 :-)

It depends what you want it for. The real thing seems more fun to me.

Daniele

On Wed, 28 Dec 2011 17:46:16 +0000, Tim Streater wrote:

In article
,
(D.M. Procida) wrote:

The Natural Philosopher wrote:

Isn't it better to get one of those emulator things and run the games
under that?

a pentium running a Z80 simulator is still faster than a z-80 :-)

It depends what you want it for. The real thing seems more fun to me.

I think in the end I found the Z80 to be too irritating. An extra set of
the main registers, yes, that's handy. But those IX and IY regs, more or
less useless.

Not if you're a compiler writer. I remember making extensive use of them.

--
Use the BIG mirror service in the UK:
http://www.mirrorservice.org

*lightning protection* - a w_tom conductor

On Wed, 28 Dec 2011 16:17:05 +0000, John Rumm
wrote:

On 28/12/2011 11:37, Frank Erskine wrote:
On Wed, 28 Dec 2011 08:51:49 +0000, wrote:

On Tue, 27 Dec 2011 23:28:46 +0000,
(D.M. Procida) wrote:

wrote:

Reflow the joints with some good honest 60/40 Lead based solder (still
legal for repairs) and a decent temperature controlled soldering iron.

Is there any problem mixing lead and lead-free solder?

Daniele


Depends on the alloy. Some of the Lead-free solders currently
available contain high quantities of Zinc. While they flow and melt
like 60/40, they are prone to corrosion.

Other mixes don't perform well at low temperatures (especially high
Tin alloys) or under vibration. Probably OK for most domestic
applications, not good at all for aerospace.

Just curious - what type of solder (if any) IS used in the aerospace
industry these days?

Quite often lead free in Europe, although it can be tricky on military
stuff where you have US manufactured primary parts (or second source -
as is usually a requirement) - since they will often come pre-tinned
with leaded solder.

I think I've got enough tin/lead (grade K) to see me out anyway :-)

Its still readily available anyway since its needed for repair work on
existing equipment. CPC do it.

Neither Maplin nor B&Q do now, though.

--
Frank Erskine

On Wed, 28 Dec 2011 21:19:19 +0000, Frank Erskine wrote:

On Wed, 28 Dec 2011 16:17:05 +0000, John Rumm
wrote:

On 28/12/2011 11:37, Frank Erskine wrote:
On Wed, 28 Dec 2011 08:51:49 +0000, wrote:

On Tue, 27 Dec 2011 23:28:46 +0000,
(D.M. Procida) wrote:

wrote:

Reflow the joints with some good honest 60/40 Lead based solder
(still legal for repairs) and a decent temperature controlled
soldering iron.

Is there any problem mixing lead and lead-free solder?

Daniele


Depends on the alloy. Some of the Lead-free solders currently
available contain high quantities of Zinc. While they flow and melt
like 60/40, they are prone to corrosion.

Other mixes don't perform well at low temperatures (especially high
Tin alloys) or under vibration. Probably OK for most domestic
applications, not good at all for aerospace.

Just curious - what type of solder (if any) IS used in the aerospace
industry these days?

Quite often lead free in Europe, although it can be tricky on military
stuff where you have US manufactured primary parts (or second source -
as is usually a requirement) - since they will often come pre-tinned
with leaded solder.

I think I've got enough tin/lead (grade K) to see me out anyway :-)

Its still readily available anyway since its needed for repair work on
existing equipment. CPC do it.

Neither Maplin nor B&Q do now, though.

Rapid did when I last looked.



--
Use the BIG mirror service in the UK:
http://www.mirrorservice.org

*lightning protection* - a w_tom conductor

In message , Frank Erskine
writes
On Wed, 28 Dec 2011 08:51:49 +0000, wrote:

On Tue, 27 Dec 2011 23:28:46 +0000,
(D.M. Procida) wrote:

wrote:

Reflow the joints with some good honest 60/40 Lead based solder (still
legal for repairs) and a decent temperature controlled soldering iron.

Is there any problem mixing lead and lead-free solder?

Daniele


Depends on the alloy. Some of the Lead-free solders currently
available contain high quantities of Zinc. While they flow and melt
like 60/40, they are prone to corrosion.

Other mixes don't perform well at low temperatures (especially high
Tin alloys) or under vibration. Probably OK for most domestic
applications, not good at all for aerospace.

Just curious - what type of solder (if any) IS used in the aerospace
industry these days?

I think I've got enough tin/lead (grade K) to see me out anyway :-)


That reminds me - Ive only got 24 500 reels left - time I bought some
more





--
geoff

On Wed, 28 Dec 2011 12:50:41 +0000,
(D.M. Procida) wrote:

The Powers That Be decided that if electronics stuff containing lead was
disposed by dumping it into landfill, the lead would leach out into the
water supply or if it was burnt, the lead would be carried in the flue
gases and spread itself all over the landscape.

... whereas it's really great for the environment for our society to
dispose of mountains of prematurely-deceased tin-whiskered electronic
junk.

That's ok, it all goes to Indian villages where the kids can earn a
few rupees a day dismantling and burning it for the gold content.
Everybody wins; except them, of course.

On 28 Dec 2011 21:32:43 GMT, Bob Eager wrote:

On Wed, 28 Dec 2011 21:19:19 +0000, Frank Erskine wrote:

On Wed, 28 Dec 2011 16:17:05 +0000, John Rumm
wrote:

On 28/12/2011 11:37, Frank Erskine wrote:
On Wed, 28 Dec 2011 08:51:49 +0000, wrote:

On Tue, 27 Dec 2011 23:28:46 +0000,
(D.M. Procida) wrote:

wrote:

Reflow the joints with some good honest 60/40 Lead based solder
(still legal for repairs) and a decent temperature controlled
soldering iron.

Is there any problem mixing lead and lead-free solder?

Daniele


Depends on the alloy. Some of the Lead-free solders currently
available contain high quantities of Zinc. While they flow and melt
like 60/40, they are prone to corrosion.

Other mixes don't perform well at low temperatures (especially high
Tin alloys) or under vibration. Probably OK for most domestic
applications, not good at all for aerospace.

Just curious - what type of solder (if any) IS used in the aerospace
industry these days?

Quite often lead free in Europe, although it can be tricky on military
stuff where you have US manufactured primary parts (or second source -
as is usually a requirement) - since they will often come pre-tinned
with leaded solder.

I think I've got enough tin/lead (grade K) to see me out anyway :-)

Its still readily available anyway since its needed for repair work on
existing equipment. CPC do it.

Neither Maplin nor B&Q do now, though.

Rapid did when I last looked.

As I said, I'm probably OK to leave a 1 lb. reel or two of proper
solder in my last will and testament, but I do have a bit of concern
for future generations. Unless somebody in the future 'discovers' a
form of solder which uses lead and tin...


--
Frank Erskine

On Wed, 28 Dec 2011 16:03:51 +0000, The Natural Philosopher wrote:
Isn't it better to get one of those emulator things and run the games
under that?

I don't think it gives you the real experience, although of course it's
fine if you just want to play the games.

I'm not sure if emulators will ever be as good as the real thing -
there's no way to emulate the feel of the keys, for instance.

cheers

Jules

Huge wrote:

On 2011-12-29, Jules Richardson wrote:
On Wed, 28 Dec 2011 16:03:51 +0000, The Natural Philosopher wrote:
Isn't it better to get one of those emulator things and run the games
under that?

I don't think it gives you the real experience,

BTW, has this been mentioned here;

http://www.raspberrypi.org/

Raspberry Pi is a great idea, and I think it's going to be successful.
At PyCon in September there was a lot of excitement about it.

But, unless it's taken up as part of some larger programme, as the BBC
Micro was 30 years ago, I am not sure exactly what niche it will find
outside a core nerd audience with a need for a small inexpensive
computer - I don't think it's going to be wildly successful.

The schools - who ought to be leaping at it - are too dull and
unadventurous to buy into it. Most people already have a big expensive
computer that can do anything this small inexpensive computer can do.

Maybe it will find traction in other parts of the world.

It's not what I actually want for myself, because it's still just a
small inexpensive PC, and there's nothing exciting about a PC to me. It
has a pretty standard hardware and software architecture; it's a
GNU/Linux box.

FIGnition - much less powerful, harder to use and much less standard -
is more to my taste as far as having fun and learning about computers
goes.

Daniele