Back when I worked in a TV repair shop as a 15 year old kid, I simply snatched the horizontal oscillator tube out of a running TV set and headed off to the tube tester in a different room. Anyone who actually knows what they are doing would NOT do this as it leaves the output tube without drive or bias.
Upon returning I found the output tube glowing nearly white, and mostly melted. I shut the TV off immediately and tried to cool things off with a fan. After cooling the horizontal output tube had the glass sucked inwards and nearly perfectly formed around the elements. Unfortunately it had soldered itself into the socket and I broke it trying to get it out before the boss got back from a service call.
I have tried several times to replicate this effect, but have failed. In each case I started with a pretty sick tube. I think a tube with strong emission is needed, but I never tried it with a good tube.
The original TV set in the shop event happened in 1968 and used a Compactron tube. We were a Philco warranty shop, so the tube was likely a 6KD6. After extraction, I replaced the output and oscillator tube and the TV worked.
Upon returning I found the output tube glowing nearly white, and mostly melted. I shut the TV off immediately and tried to cool things off with a fan. After cooling the horizontal output tube had the glass sucked inwards and nearly perfectly formed around the elements. Unfortunately it had soldered itself into the socket and I broke it trying to get it out before the boss got back from a service call.
I have tried several times to replicate this effect, but have failed. In each case I started with a pretty sick tube. I think a tube with strong emission is needed, but I never tried it with a good tube.
The original TV set in the shop event happened in 1968 and used a Compactron tube. We were a Philco warranty shop, so the tube was likely a 6KD6. After extraction, I replaced the output and oscillator tube and the TV worked.
I was 15 years old and making $1 per hour, which was below the Federal minimum wage. As soon as I turned 18 I took over the repair shop at the #1 Olson Electronics store in the US (next to the U of Miami).
The TV shop folded soon after that as TV's started becoming solid state. They are a bit harder to fix with a VTVM and a tube tester. The owner did have a good knowledge of Philco TV's, and could usually look at the picture and tell me what to change....if there was a picture. Something other than a Philco TV, or other than a TV, was my domain. If he can find me, I'll give him his dollar back. And a couple of tubes!
The TV shop folded soon after that as TV's started becoming solid state. They are a bit harder to fix with a VTVM and a tube tester. The owner did have a good knowledge of Philco TV's, and could usually look at the picture and tell me what to change....if there was a picture. Something other than a Philco TV, or other than a TV, was my domain. If he can find me, I'll give him his dollar back. And a couple of tubes!
I just lied about my age and started working at Lafayette at 14. I installed car stereos and got paid cash. The guy hired me when he realized how much business I was taking away from him. I still installed stereos in my father's driveway.
I got hired at Lafayette again in college, same gig. That was a pretty good job for a teenager.
Radio Shack wouldn't hire me, even when I was in college, because I didn't have a college degree. How silly. I was a freaking wizard by the time I was 15. What a stupid, stupid company. I was already working summers at IBM by the time I was 19. No way in hell I'd work for "The Shack"
after that.
Corporate types and marketers are so idiotic.
I got hired at Lafayette again in college, same gig. That was a pretty good job for a teenager.
Radio Shack wouldn't hire me, even when I was in college, because I didn't have a college degree. How silly. I was a freaking wizard by the time I was 15. What a stupid, stupid company. I was already working summers at IBM by the time I was 19. No way in hell I'd work for "The Shack"
after that.Corporate types and marketers are so idiotic.
>Until then I have an extra fan blowing across the condenser coils.
If it was me, that'd be the permanent solution. Cooled, I bet that compressor still has several years of service left. According to what I'm hearing, maybe competitive with the longevity of a "new" fridge...
Speaking of fans and tubes, one guy in the cal lab at Digital noticed I was interested in an old Optimation AC source / power amplifier they had. He signed it out to the recycle store, where I later picked it up. It had 8 6CA7s cooled by a 120mm AC fan that just ran full blast when you turned the amp on.
I assume they had issues with the tubes melting without the fan... So, there's a way to prevent that - if you can stand the noise!
If it was me, that'd be the permanent solution. Cooled, I bet that compressor still has several years of service left. According to what I'm hearing, maybe competitive with the longevity of a "new" fridge...
Speaking of fans and tubes, one guy in the cal lab at Digital noticed I was interested in an old Optimation AC source / power amplifier they had. He signed it out to the recycle store, where I later picked it up. It had 8 6CA7s cooled by a 120mm AC fan that just ran full blast when you turned the amp on.
I assume they had issues with the tubes melting without the fan... So, there's a way to prevent that - if you can stand the noise!
I have always looked younger than I am, but at 15 I could pass for 10.
Florida required "work papers" for anyone working under the age of 16. These mostly involved the school system and "dropout prevention," since Florida was, and still is pretty far down the list in high school graduation rates. A business employing undocumented under age kids could lose their business license. National chains like burger joints and gas stations that employed kids did get visited, but I doubt the TV shop even knew about the requirement.
I was enrolled in a three year long vocational electronics program and it was the school system that got me the job in the TV shop, and did all the paperwork.
It was soon decided that I could fix TV's better than the owner could, and in-home service customers didn't like the "owner's kid" being inside their TV, so I stayed in the shop fixing stuff.
The Olson Electronics and the Lafayette Radio Electronics store both had "bargain tables" where they sold blemished or defective items for cheap. I bought from both. The manager of Olson's had asked me what I was doing with the stuff, so I told him that I fixed it and sold it at school. He said that his tech told him it couldn't be fixed, and I replied that he needed a new tech.....but Olson policy required age 18, which was several months after I left high school. I started at Olson right after my birthday.
There were a few, very few, people that did engineering work at Motorola without a college degree. Of my three closest non-degreed friends, the other two came to Motorola from Radio Shack.
The non-degreed people were called "electrical designers" and typically one or two pay grades behind a comparable engineer's salary. By the late 80's designers were an endangered species, so I took the "get an engineering degree at the company's expense" route. Only one other non degreed person besides me got his degree via this route before the plug was pulled on the program.
Florida required "work papers" for anyone working under the age of 16. These mostly involved the school system and "dropout prevention," since Florida was, and still is pretty far down the list in high school graduation rates. A business employing undocumented under age kids could lose their business license. National chains like burger joints and gas stations that employed kids did get visited, but I doubt the TV shop even knew about the requirement.
I was enrolled in a three year long vocational electronics program and it was the school system that got me the job in the TV shop, and did all the paperwork.
It was soon decided that I could fix TV's better than the owner could, and in-home service customers didn't like the "owner's kid" being inside their TV, so I stayed in the shop fixing stuff.
The Olson Electronics and the Lafayette Radio Electronics store both had "bargain tables" where they sold blemished or defective items for cheap. I bought from both. The manager of Olson's had asked me what I was doing with the stuff, so I told him that I fixed it and sold it at school. He said that his tech told him it couldn't be fixed, and I replied that he needed a new tech.....but Olson policy required age 18, which was several months after I left high school. I started at Olson right after my birthday.
There were a few, very few, people that did engineering work at Motorola without a college degree. Of my three closest non-degreed friends, the other two came to Motorola from Radio Shack.
The non-degreed people were called "electrical designers" and typically one or two pay grades behind a comparable engineer's salary. By the late 80's designers were an endangered species, so I took the "get an engineering degree at the company's expense" route. Only one other non degreed person besides me got his degree via this route before the plug was pulled on the program.
Speaking about Olson, and Lafayette....
About 3 years back, my neighbor brought me a cosmetically perfect Lafayette LR-9090 receiver.
Not a scratch or mark on it.
It neeeded the usual stuff, dirty switches, a couple caps, dial lamps, etc.
Beefy build quality for sure, but definitely worth the effort, effortless sonics for 90W/ch.
Afterwords, I was stunned at what it originally cost!
And I still have my old Olson transistor tester, still works, but sitting unused up on a shelf, dusty.
About 3 years back, my neighbor brought me a cosmetically perfect Lafayette LR-9090 receiver.
Not a scratch or mark on it.
It neeeded the usual stuff, dirty switches, a couple caps, dial lamps, etc.
Beefy build quality for sure, but definitely worth the effort, effortless sonics for 90W/ch.
Afterwords, I was stunned at what it originally cost!
And I still have my old Olson transistor tester, still works, but sitting unused up on a shelf, dusty.
Attachments
Had a model railway power booster not behaving.
It takes in DCC signals from a DCC encoder and boosts them to 2.5 amps for accessories or another track.
I found one edge of the opto-coupler which reads the DCC signal was about 10uS delayed.
So I blamed the opt-coupler. I revisited the spec but no it can do 10mega bits per second and my signal is around 10KHz.
So replaced it in case faulty but still the same.
The only other thing in the circuit is reverse protection diode and a current limiting resistor.
I thought maybe the 1n4004 reverse protection diode was maybe a bit slow changing phase so swapped it out for a 1n4148. Hey presto works.
Just had the deadtime to adjust (1.5uS) and then all works fine.
It takes in DCC signals from a DCC encoder and boosts them to 2.5 amps for accessories or another track.
I found one edge of the opto-coupler which reads the DCC signal was about 10uS delayed.
So I blamed the opt-coupler. I revisited the spec but no it can do 10mega bits per second and my signal is around 10KHz.
So replaced it in case faulty but still the same.
The only other thing in the circuit is reverse protection diode and a current limiting resistor.
I thought maybe the 1n4004 reverse protection diode was maybe a bit slow changing phase so swapped it out for a 1n4148. Hey presto works.
Just had the deadtime to adjust (1.5uS) and then all works fine.
It was just a first attempt pcb to test the principle so was a bit rough.
The next revision is a bit better and a bit smaller.
I also increased thickness of some of the power tracks.
The LM317 reg's control components and decoupling were miles away from it which has been fixed.
Amazing it worked at all !
The next revision is a bit better and a bit smaller.
I also increased thickness of some of the power tracks.
The LM317 reg's control components and decoupling were miles away from it which has been fixed.
Amazing it worked at all !
A Dynaco SCA35.
And one 7199 was replaced with a non-marked dual triode, thus one channel was dead.
Replaced with a new 7199 .
power tubes ( one was flashing ) replaced with a matched quad.
Potentiometers was bad, volume really bad. Changed to my last 250k /W loudness
Repared the disconnected mono/stereo
cleaning and vacuum
Nice to be at service
And one 7199 was replaced with a non-marked dual triode, thus one channel was dead.
Replaced with a new 7199 .
power tubes ( one was flashing ) replaced with a matched quad.
Potentiometers was bad, volume really bad. Changed to my last 250k /W loudness
Repared the disconnected mono/stereo
cleaning and vacuum
Nice to be at service
Mmm an audio grade wirewound 2% resistor and then open circuit. The joy of cheap stuff.
Hi Jean-Paul,
It wasn’t a cheap resistor at all, it was so called high-end “Audio Grade” quality. I bought it for another purpose, but it ended up in the position between chassis and audio ground.
To be honest, I’ve seen quite a few ceramic wirewound resistors blown over the years. Some turned browd or dark gray and were still OK, some drifted and some opened up.
The replacement resistor will be a better, ruggidized type.
Regards, Gerrit
It wasn’t a cheap resistor at all, it was so called high-end “Audio Grade” quality. I bought it for another purpose, but it ended up in the position between chassis and audio ground.
To be honest, I’ve seen quite a few ceramic wirewound resistors blown over the years. Some turned browd or dark gray and were still OK, some drifted and some opened up.
The replacement resistor will be a better, ruggidized type.
Regards, Gerrit
Out of curiosity, crack it open and inspect the inside guts.
Something tells me it might have a 2 watt molded inside (china)
Because I've also seen caps of all types labeled "audio grade" and inside is a tiny crap cap.
This sham goes for hard drives and flashdrives as well.
Amazing how they think they can get away by robbing people.
I wound up having to replace the brushes on my 'weed-wacker'...this is the third set now. A foam spacer/insert/vibration damper enveloping the motor in the housing has long since deteriorated, some GP foam fixed that...the commutator is rather "rough" looking, very wavy, but no bridges are occurring. Each time I'm taking some fine grit sandpaper to the commutator...but not "machining" it flat...it melted a field-coil wire too once. I'm not letting the cooling vents get clogged with grass trying to keep it cool....bearings are still OK.
-------------------------------------------------------------------------Rick....
-------------------------------------------------------------------------Rick....
I've been using the same cheap old Toro weed-wacker since 2006 - 15 years now.
Never done a thing to it, maybe oil the bottom bearing years ago.
Budget "bump feed" model, I think I only paid $39.95 for it... it doesn't want to die!
Use a thin blade to clean between commutator segments when doing maintenance.
Use synthetic rubber foam, high temp if needed, though I don't think you will get it in a small quantity.
Insulating foam from engine compartments of cars will work well, it is high temperature stuff.
I use front axle grease, it is stronger and higher temperature rated than regular EP2 grease, for bearings nowadays. It seems to adhere better too.
Use synthetic rubber foam, high temp if needed, though I don't think you will get it in a small quantity.
Insulating foam from engine compartments of cars will work well, it is high temperature stuff.
I use front axle grease, it is stronger and higher temperature rated than regular EP2 grease, for bearings nowadays. It seems to adhere better too.