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Resistor behavior
- Thread starter 62vauxhall
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If I remember right......
#1 failure mode is high leakage or shorting.
#2 High ESR.
#3 Open or low cap value.
I kinda remember failures caused by ripple or noise riding on a DC voltage which basically exceeded the voltage rating of the cap. The caps would physically blow apart in some conditions.
Robert
#1 failure mode is high leakage or shorting.
#2 High ESR.
#3 Open or low cap value.
I kinda remember failures caused by ripple or noise riding on a DC voltage which basically exceeded the voltage rating of the cap. The caps would physically blow apart in some conditions.
Robert
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Needed some shrink tube so drove "into town" to get some. I should know better than to do that mid morning on a Saturday. An hour and a half round trip turned into 4.
Before I left I did some reading about tantalum capacitors and it would appear a new-ish generation of ceramics (monolithic) have replaced or can replace them. i got some of those (10uF 50V) and some tantalum's again plus some 100V and 160V 10uF electrolytics. During my morning "research" I read that ESR gets lower in electrolytic's as voltage gets higher.
I am strongly inclined to use the monolithic ceramic - non polarized though it is. Do you guys concur?
Before I left I did some reading about tantalum capacitors and it would appear a new-ish generation of ceramics (monolithic) have replaced or can replace them. i got some of those (10uF 50V) and some tantalum's again plus some 100V and 160V 10uF electrolytics. During my morning "research" I read that ESR gets lower in electrolytic's as voltage gets higher.
I am strongly inclined to use the monolithic ceramic - non polarized though it is. Do you guys concur?
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Well, encouragement so far. Put in that ceramic monolithic and resistor R27 stayed cool to the touch so thanks to one and all.
Still blows me away that I looked for a C29 on the board so many times and overlooked it each and every one. Preconception, assumption, whatever - it never occurred to me that 25V 10uF could mean anything but an electrolytic.
With any luck, I will be able to solder all those wires back onto the board without incident. But the fun part will be looking for the fasteners I removed three years ago and when found, remembering how it went back together.
Regarding that earlier photo I inserted of the tantalum saying it was green but looked black, turned out it was neither. It was actually blue - once.
Damn camera - won't properly shoot Macro anymore. Time to start looking for another $20 Craigslist Special.
Still blows me away that I looked for a C29 on the board so many times and overlooked it each and every one. Preconception, assumption, whatever - it never occurred to me that 25V 10uF could mean anything but an electrolytic.
With any luck, I will be able to solder all those wires back onto the board without incident. But the fun part will be looking for the fasteners I removed three years ago and when found, remembering how it went back together.
Regarding that earlier photo I inserted of the tantalum saying it was green but looked black, turned out it was neither. It was actually blue - once.
Damn camera - won't properly shoot Macro anymore. Time to start looking for another $20 Craigslist Special.
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Well, that high was short lived but good point.
No more on this particular board but reviewing the parts list, there are some scattered around elsewhere.
*2 on what's called Amplifier A board - 16V 10uF
*2 on what's called Amplifier B board - 35V 0.15uF
*2 each on Dolby B Encode & Decode sections 16V 10uF.
So far, I've been able to identify Amp A & B and they don't look too terribly hard to dislodge. Maybe with them out of the way, the Dolby board(S) will become evident.
So back to the parts store on Monday and the tribulations continue.
No more on this particular board but reviewing the parts list, there are some scattered around elsewhere.
*2 on what's called Amplifier A board - 16V 10uF
*2 on what's called Amplifier B board - 35V 0.15uF
*2 each on Dolby B Encode & Decode sections 16V 10uF.
So far, I've been able to identify Amp A & B and they don't look too terribly hard to dislodge. Maybe with them out of the way, the Dolby board(S) will become evident.
So back to the parts store on Monday and the tribulations continue.
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Yes, scarce indeed.
When I started frequenting them, there were four I used to hit. One went all gung-ho with metal detectors and prospecting so now a waste of my time. Another went heavy into A/V hardware, 3D printers, kits, etc. but never have what I want and the poor few semi-conductors they sell is limited to NTE.
The longest standing one was in business since 1971/72 but shut down for good a few months ago. A lot of people got speaker foams there and I bought lots of belts, bulbs and long obsolete things they still had on hand. They also had thousands of tubes and a couple of good ol' drugstore tube testers for customers to use. A grandfather started the business and his son and grand-sons were the staff. Then he died and not long after, his son. The grand kids and their mom decided to shut it down for their own reasons.
The fourth is one that opened in the late 1970's. Until fairly recently I never bought a lot there, preferring instead the one that recently closed. But within the last two years, they expanded, moved to a nicer, larger store and have gotten a hell of a lot busier. Although it is a Chinese family who runs it and consequently sell mostly stuff sourced in Asia, I've never had any complaints about what I've bought there - no counterfeits that I've heard of. I don't think they'd risk their reputation. There's a really good selection of parts, chemicals, hardware, supplies etc. and I've even had special orders made for a few transistors. When I need stuff I go there first but if I come away dry or mostly dry, I use the online usual's.
I will miss those bulbs, belts and foams though.
When I started frequenting them, there were four I used to hit. One went all gung-ho with metal detectors and prospecting so now a waste of my time. Another went heavy into A/V hardware, 3D printers, kits, etc. but never have what I want and the poor few semi-conductors they sell is limited to NTE.
The longest standing one was in business since 1971/72 but shut down for good a few months ago. A lot of people got speaker foams there and I bought lots of belts, bulbs and long obsolete things they still had on hand. They also had thousands of tubes and a couple of good ol' drugstore tube testers for customers to use. A grandfather started the business and his son and grand-sons were the staff. Then he died and not long after, his son. The grand kids and their mom decided to shut it down for their own reasons.
The fourth is one that opened in the late 1970's. Until fairly recently I never bought a lot there, preferring instead the one that recently closed. But within the last two years, they expanded, moved to a nicer, larger store and have gotten a hell of a lot busier. Although it is a Chinese family who runs it and consequently sell mostly stuff sourced in Asia, I've never had any complaints about what I've bought there - no counterfeits that I've heard of. I don't think they'd risk their reputation. There's a really good selection of parts, chemicals, hardware, supplies etc. and I've even had special orders made for a few transistors. When I need stuff I go there first but if I come away dry or mostly dry, I use the online usual's.
I will miss those bulbs, belts and foams though.