[sdiy] advice please -- aging chips and caps
Martin.Czech at micronas.com
Mon Aug 11 09:58:04 CEST 2003
Except maybe very old chips from the dawn of CMOS integration,
where the Al recepy was not so good. Since at least 1980
mixtures of Al-Si-Cu
are used, also to make migration less probable.
Temperature has a very large influence.
An example process has the following data:
T 80C 100C 125C
Jmax 2 1 0.5 mA/um
(the semiconductor guys think 2D, so that's why mA/um and not mA/um^2
It is not likely that the synth is running at Tj=125C all day long.
Yes , a mains switch for all the gear in your studio, and another set of switches
to power unly the used gear is a good thing to have.
From: James Patchell [mailto:patchell at cox.net]
Sent: Samstag, 9. August 2003 23:30
To: synth-diy at dropmix.xs4all.nl
Subject: Re: [sdiy] advice please -- aging chips and caps
Personally, I wouldn't worry about the IC's. Especially, the 4000
series. By todays standards, the 4000 series is a very crude IC (large
features). I have no idea what process is used to make them now, or even
then, but somehow I just don't seem to think of metal migration and 4000
series in the same thought (I could be wrong).
My understanding of metal migration is that you need a high
current density flowing through the conductor (how high?? don't know) to
make this happen. Since the 4000 series is both crude and low current, I
would put this at the bottom of things to worry about...
I would be more inclined to worry about certain vendors parts (as
was discussed a couple of months ago)...
At 10:33 AM 8/9/2003 -0800, Scott Gravenhorst wrote:
>I thought the same thing...
>Actually, the URL supplied is rather interesting. I didn't know
>about "metal migration".
>Are recently manufactured ICs still subject to this? If the old
>ones only last 15 years (expected life), then what of new ones?
> I'd prefer that they outlast *me*. This is pertinent for me
>because I have a 4000 series fetish.
>I'm all ears... er eyes...
>Tim Ressel <madhun2001 at yahoo.com> wrote:
> >I'd replace all the electrolytics.
> >Replace the 4000's??? I've never heard of that. The
> >only thing I can think of is if the ICs were stressed
> >by ESD hits. I'd leave them until something fails.
> >--- john mahoney <jmahoney at gate.net> wrote:
> >> Having read Scott Rider's article "Things to Know
> >> When Repairing Vintage
> >> Synthesizers"
> >> (http://www.oldcrows.net/~oldcrow/synth/tips.txt), I
> >> am now a
> >> little concerned about my Korg Mono/Poly, which has
> >> reached adulthood
> >> (assuming that synth years = human years).
> >> Basically, Scott says to replace
> >> all old 4000 series CMOS chips as well as certain
> >> types of caps.
> >> My questions for you folks:
> >> (1) Many of you have years of experience. Have you
> >> seen signs of CMOS
> >> senility or caps with Alzheimer's?
> >> (2) Should I replace the "at risk" components now,
> >> even though the synth is
> >> working perfectly? Or, wait and see, but *if*
> >> something goes bad then
> >> replace everything as he suggests. I'd like to add a
> >> few extra
> >> inputs/outputs/patchpoints to the Korg, so I have
> >> reason to do surgery.
> >> (See? This is a DIY question!)
> >> (3) Given the parts list below, do you see any parts
> >> that I should try to
> >> obtain now, just in case? For example, if the SSM
> >> chips are available,
> >> should I stock some? (I don't even know if the SSM
> >> chips are available
> >> anymore!)
> >> (4) Oh, yeah: What's the difference between the
> >> HD14000 series and the
> >> normal 4000 series, if any?
> >> ICs in the Mono/Poly (thanks to the excellent Zen
> >> Mono/Poly website):
> >> SSM2044 4-pole voltage controlled filter
> >> SSM2033 Voltage controlled oscillator (Qty: 4)
> >> MM5837 Digital noise source
> >> Intel 8049 8mhz CPU
> >> HD14007UBP Dual complementary pair + inverter
> >> HD14013BP Dual D flip-flop
> >> HD14042BP Quad latch
> >> HD14066BP Analog CMOS switch
> >> HD14069UBP Hex inverter
> >> HD14071 Quad "or" gate
> >> HD14174BP Hex flip-flop
> >> MC14504 Hex level shifter
> >> NJM4556 Dual high-current op-amp
> >> NJM4558DV Dual op-amp
> >> M5230L Variable output voltage regulator
> >> TL072 Dual J-FET operational amplifier
> >> Thanks to everyone for any and all insight you can
> >> offer.
> >> --
> >> john
> >Do you Yahoo!?
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