wrote:
My wife and son are both E.E.'s and their explanation is that IC's
begin to degrade slowly as a result of impurituies in the wafer.
Simple components like capacitors dry out and resistors begin to open
up. Wish I knew more, but I can hear what they tell me in the radios
I've owned. I owned one of the comparison radios, the Panasonic
RF5000b. Big beast of a 24 pound radio with four antennas. It was
pretty insensitive by any measure. Sure it would catch the big
nighttime SW's but that was about it. Other radios, such as a Radio
Shack DX150b were still pretty sensitive (and still raspy sounding)
after 25 years, so the rate of degradation isn't a constant.

Do a net search on "eletro-migration".
Over time the electrons carry some of the ions that make
junctions either P or N. Electro-migration increases with heat,
I think it doubles for every 3C degree increase. This is why
overclocking CPUs cn lead to unexpected failures.
Terry

wrote:
wrote:
My wife and son are both E.E.'s and their explanation is that IC's
begin to degrade slowly as a result of impurituies in the wafer.
Simple components like capacitors dry out and resistors begin to
open
up. Wish I knew more, but I can hear what they tell me in the
radios
I've owned. I owned one of the comparison radios, the Panasonic
RF5000b. Big beast of a 24 pound radio with four antennas. It was
pretty insensitive by any measure. Sure it would catch the big
nighttime SW's but that was about it. Other radios, such as a
Radio
Shack DX150b were still pretty sensitive (and still raspy sounding)
after 25 years, so the rate of degradation isn't a constant.

Do a net search on "eletro-migration".
Over time the electrons carry some of the ions that make
junctions either P or N. Electro-migration increases with heat,
I think it doubles for every 3C degree increase. This is why
overclocking CPUs cn lead to unexpected failures.
Terry


JS That's good information. And it's not too surprising that IC's
are temperature sensitive since we use heat sinks and fans to dissipate
heat. Could also be why some of the Radio Shack Pro scanners tended to
die early deaths when a faster crystal was added.

In article .com,
says...
http://cgi.ebay.com/ws/eBayISAPI.dll...5895 535&rd=1


Interesting price. Remember ?? a couple of months back I posted
an inquiry saying I found one of these in working conditon on a back
shelf in the stock room at work...did anyone have any doc's to assist my
restoration ??

The radio is currently in service in our undergrad analog circuits
lab so the students can listen to something more interesting than top
40's when they're in there after hours trying to finish up.

It still needs an unkludged bandswitch knob, and I'd love to have
a copy of the alinement data.

wrote in message
ups.com...

wrote:
My wife and son are both E.E.'s and their explanation is that IC's
begin to degrade slowly as a result of impurituies in the wafer.
Simple components like capacitors dry out and resistors begin to
open
up. Wish I knew more, but I can hear what they tell me in the
radios
I've owned. I owned one of the comparison radios, the Panasonic
RF5000b. Big beast of a 24 pound radio with four antennas. It
was
pretty insensitive by any measure. Sure it would catch the big
nighttime SW's but that was about it. Other radios, such as a
Radio
Shack DX150b were still pretty sensitive (and still raspy
sounding)
after 25 years, so the rate of degradation isn't a constant.

Do a net search on "eletro-migration".
Over time the electrons carry some of the ions that make
junctions either P or N. Electro-migration increases with heat,
I think it doubles for every 3C degree increase. This is why
overclocking CPUs cn lead to unexpected failures.

So, does that mean it might not be a bad idea to
do some restoration work (or have it done) on
the newer radios when they reach 20 years or so,
sort of like the older tube radios?? I imagine that
the caps last longer than the old paper caps or black
beauties, but fixing up an R-70 or an FRG-7700 (if
in otherwise decent shape) hadn't occured to me before.

--Mike L.

I guess it all depends on the age of the radio(s) and how much they need
restoring and how much one wants to spend.We have some Very stormy
weather here right now (Jackson,Mississippi) with straight line winds
and at 3:55 PM this afternoon,I thought that gust of wind was going to
blow my house over. www.wapt.com is the best tv station here for
constant stormy weather reports.There isn't anything that scares me
worst than tornados.Emergency vehicles have been going along Highway 80
since not long after daybreak this morning and they are still going
right now.
cuhulin

I've had two Sony CRF-5100s in my time. The first I bought was from a school
rummage sale about 15 years ago for $8. Another was from a hamfest a few
years ago for $85. Neither was terribly impressive and I sold them for
roughly what I had in them.

"BDK" wrote in message
...

A friend's dad had a huge collection of receivers from the late 50's
until he died in 1981, and this was one of the portables. The Sony
wasn't great when it was new, let alone now...

Michael Lawson wrote:


wrote in message
ups.com...

wrote:
My wife and son are both E.E.'s and their explanation is that IC's
begin to degrade slowly as a result of impurituies in the wafer.
Simple components like capacitors dry out and resistors begin to
open
up. Wish I knew more, but I can hear what they tell me in the
radios
I've owned. I owned one of the comparison radios, the Panasonic
RF5000b. Big beast of a 24 pound radio with four antennas. It
was
pretty insensitive by any measure. Sure it would catch the big
nighttime SW's but that was about it. Other radios, such as a
Radio
Shack DX150b were still pretty sensitive (and still raspy
sounding)
after 25 years, so the rate of degradation isn't a constant.

Do a net search on "eletro-migration".
Over time the electrons carry some of the ions that make
junctions either P or N. Electro-migration increases with heat,
I think it doubles for every 3C degree increase. This is why
overclocking CPUs cn lead to unexpected failures.

So, does that mean it might not be a bad idea to
do some restoration work (or have it done) on
the newer radios when they reach 20 years or so,
sort of like the older tube radios?? I imagine that
the caps last longer than the old paper caps or black
beauties, but fixing up an R-70 or an FRG-7700 (if
in otherwise decent shape) hadn't occured to me before.

You can't restore ICs, of course, but you can replace auxilary
transistors, capacitors, resistors, etc. I know that some of the older
transistorized clock radios (the ones made in Japan prior to the
microchip age) tended to have the radio die gradually over time. This
happened prior to the motor which flipped the numbers dying. I know that
happened to an old 1971 Juliette which was my first radio. The radio
gradually got weaker and weaker and finally went silent, then the
numbers stopped turning. Those clock radios were pretty cheaply made and
were not worth restoring, but a tabletop SW radio like a 7700 would
definitely be worth restoring if it was otherwise pretty good.


----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==----
http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups
----= East and West-Coast Server Farms - Total Privacy via Encryption =----

wrote:

Collectors have a whole different set of reasons for buying a radio
than users. Compare the price for that radio with the $600.00 for an
FRG-7, $800.00 for a Sony 6800, $3,000 for a SonyCRF320 or $800.00 for
a Zenith TO. Prices no user would contemplate, but several collectors
would not blink twice at.

The Sony you mentioned was one of many luggable radios in it's time.
It probably priced out lower than but was meant to compete as a
reasonably priced alternative to the Panasonic Rf-5000a, Zenith TO,
Nordmende & Grundig offerings. All were reasonable performing radios
in their time with notably pleasant audio - much mellower than anything
found today. In all cases time will have taken a toll on their
electronics and there's a good chance controls will be noisy, dial
accuracy will be frustrating, plastic started to fade, etc. For my
purposes the Sony would be fun to use for a while, but that's about it.
That there have been 32 bids to date tells me there's more than one
collector that have a different view.


wrote:

http://cgi.ebay.com/ws/eBayISAPI.dll...5895 535&rd=1


Don't forget the GE World Monitor, another competitor in the TO type
radio derby of the 60s. I have an early version of the World Monitor, a
P990C that my grandfather bought new in 1964. He bought it for the FM
band, this at a time when most small transistor radios were MW only. He
paid $100 for it, which was a lot of money in 1964. It still works well,
and has the original AC adaptor (he used it in his auto repair shop). I
could probably get $800 for it on ebay, not that I would risk the wrath
of my grandfather by doing so.

Note that the seller has amended his auction to argue that the Sony is
worth $400. He originally put it up for $19.95.


----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==----
http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups
----= East and West-Coast Server Farms - Total Privacy via Encryption =----

In article ,
says...
I've had two Sony CRF-5100s in my time. The first I bought was from a school
rummage sale about 15 years ago for $8. Another was from a hamfest a few
years ago for $85. Neither was terribly impressive and I sold them for
roughly what I had in them.

"BDK" wrote in message
...

A friend's dad had a huge collection of receivers from the late 50's
until he died in 1981, and this was one of the portables. The Sony
wasn't great when it was new, let alone now...




When my friend's dad died, he auctioned off almost all his stuff,
keeping the nicer R390A of two his dad had, and a nearly new looking
Hammarlund HQ180. The rest went, along with a seemingly endless supply
of parts he built up over the years. Half the attic was stocked with NOS
receiving tubes, and a large number of high power linear amp tubes and
other transmitter tubes. His dad's so called "friends" attempted to
steal all his stuff after he died, and were really upset when my friend
didn't give them the stuff for a tenth it's real worth.


I think the CRF-5100 went for 90 or 100 bucks, but it wasn't one of the
ones I wanted, so I really didn't pay attention to the bids on it. I
wanted the Drake R7, but was outbid almost instantly. It ended up nearly
what a new one cost..

BDK

For a well designed integrated circuit, the most likely thing to fail
is the package, which in turn leads to failure in the bonding. Consumer
grade electronics use porous plastic packages, while the military forks
out for ceramic.

It is possible to get ion contaminator from how the wafers were handled
(such as a moron touching the edge), but the associated threshold
shifts show up very soon. I'm not sure if you can find this on the net,
but all the IC companies do some sort of die seal to reduce this
problem.

I'd blame the capacitors, especially tantalum. Resistors should be
stable.

Regarding electromigration, this is also well understood and
compensated for in the design process.

I can tell you that most chips coming to a failure analysis lab are
damaged by electrical overstress. Often a power surge will shoot right
through the power supply and zap some chip. [Some radios are "always
on" if hooked up to the AC mains, so a radio that is off can get
zapped.] Second comes latch-up related problems, not exactly the fault
of the chip, i.e. all chips using reverse biased diode isolation will
latch under some external conditions.