more power har har har!

[Janitor Tzap]

pretty good..but it ain't all that..me and friends used to play stun gun tag at a friends house.. his dad was a sherriff.. and just happened to have 2-3 stun guns.
they hit hard. but we had a lot of fun too...

Some peoples kids!

Well, back in my earlier days.......
Some delinquent geniuses had discovered that tin foil gum rappers,
made for simple circuit breaker poppers, when stuffed into an AC outlet.
Though, these idiots were doing it while the outlets were live.
Thus, they'd burn their fingers while sticking the rapper into the outlet.

I will relate a story that is sort of electrically related.........

At my old High School we had a Electronics Room.
But due to budget cuts, the advanced Electronics course was dropped,
and the Electronics Room was going to be re-purposed.
The instructor asked if some of us students would help out getting the room cleaned up.
So, me and three other guys, {who were friends} said we'd help.
Well, the Electronics Room had several old beat up B&W sets that were pretty much just junk.
The instructor told us to take them out to the dumpster.
We looked at several of the sets, and the CRT's were still sealed holding a vacuum.
A wicked idea came to mind.{He-he-he!}
We quickly stripped two of the CRT's out of the sets, and headed to the school roof.
Looking down from the roof, we could see the schools garbage dumpster just bellow.
One of the guys went and opened the top of the dumpster,
then moved any bags into corners so there was nothing to absorb impact.
With safety goggles on, that we got from the Chem Lab.
We dropped the first CRT into the dumpster.
There was a POP! with the tinkling of glass as it shatter in the dumpster.
Then we dropped the second CRT into the dumpster with similar results.
Our Instructor came running, wondering what was making the noise.
He couldn't really punish us, because we were doing what he asked us too do.
But the next day, when we went to finish throwing out the rest of the sets.
The glass nipples on the back of the all the CRT's were snapped off.


Signed: Janitor Tzap

[Lenp]

About shocks...

Years ago I developed a small skin tag on my eyelid. My wife, an R.N., told me that they are routinely removed using a Hyfrecator. This is an instrument that develops a small high frequency spark that is used to cauterize tissue. Later I remembered that I actually had an antique hyfrecator in my over grown gadget collection.

Next day, without the benefit of professional assistance, I fired the unit up, came close to the skin tag and zapped it.
Kazoooow! Bright lights, head jerk, off the chair, on the floor in a zero microsecond moment.
My resident RN neglected to tell me ....... they numbed the area first!
BUT....
The skin tag never returned!

Len

[jwax]

And I thought I had a large "gadget collection"!
No hyfrecator's at all!

[dacflyer]

lol.. CRT's such fond memories when i was working on arcade games for a living.
i used to dispose of crt's a lot.. bad ones.
usually i'd out it in the dumpster, then blindly swing a hammer to knock the neck off. and usually it would break off and you'd hear the hiss or a poooshhhhh... well one day i took a whack at one to do as i always did.. i guess i missed my mark because this tube went KaBOOOOOMMMMM
all the guys in the office came running to the shop to check on me fearing the worse. and thay fine me hysterically laughing. that was so loud ! i apparently missed the neck and hit the side of the tube.
after the guys seen i was ok, they went back to the office..
i heard one mumble " that guy is a frigging nut"...lol

i never knew a tube could be that powerful on imploding. thats the reason i put them in the dumpster and duck down as i swing the hammer inside to break them..
i have since devised a easier way to do it now.. i'd use a flat file.. take the corner edge score a line on the neck. then heat it with a torch for a sec. and then the neck would get a hairline crack and slowly leak down safely..

[Janitor Tzap]

i never knew a tube could be that powerful on imploding. thats the reason i put them in the dumpster and duck down as i swing the hammer inside to break them..
i have since devised a easier way to do it now.. i'd use a flat file.. take the corner edge score a line on the neck. then heat it with a torch for a sec. and then the neck would get a hairline crack and slowly leak down safely..

Yeah, some of the Monitor CRT's had a very high vacuum in them.
Because the better the vacuum, the longer the life of the electron guns in the CRT.
This was important for the Video Arcade Owners.
Since the Video Games were running non-stop 24/7.
Thus, they didn't want to have repair guys coming out every few months.
Replacing the monitors in the games.

On some of the early Flat Screen CRT's, they had a high vacuum.
Because of problems getting the Mask, and the Sealing grommet around the front of the screen from leaking over time.
These were used mainly in computer monitors.
So if the CRT seals did leak.
It was hoped that it was slow enough that it wouldn't have any significant effects till some two years later.
When most companies had a policy of replacing computer monitors every two years any way.
But as it was, I was sending lots of CRT's back to the manufacturer, because they failed much sooner than planned.

Speaking of removing the vacuum on the CRT......
My instructor always said the easiest, and safest way,
was just snapping the nipple off the end of the tube.
The nipple was in the middle of the pins for the Electron guns.
So, we'd just take a big set of diagonal cutters, and cut the pins and glass nipple off at the same time.


Signed: Janitor Tzap

[Lenp]

Years ago I removed the chassis from a portable TV under repair and in a wink, I saw the front half of the set, minus the chassis, flip over the edge of the bench.

CRT? Gone!,
Cabinet? Gone!,
Customer?...Gone too!

Ah Those were the days. Spending a long time getting the zillion purity and convergence tweaks just right, then the new CRT goes gassy.....

Len

[Janitor Tzap]

Years ago I removed the chassis from a portable TV under repair and in a wink, I saw the front half of the set, minus the chassis, flip over the edge of the bench.

CRT? Gone!,
Cabinet? Gone!,
Customer?...Gone too!

Ouch!
Yeah, some of the sets were rather tipsy.

Oh, here's a good one....

While taking Advanced Electronics at the local VoTech.
The class would take in TV's, Radio's, Etc, to be repaired by us students.
A guy dropped off his JC Penny 25" Color Television that had a problem with the tuner,
{Couldn't get channel 2 to work}.
Note: This was a community type VoTech,
in which kids from the local High Schools were coming in too learn Radio\TV repair.
Well, the instructor let the High Schooler's have a crack at the set.
Instead of looking at the work sheet on the TV, they just started pulling the set apart.
They got it almost completely torn down.
When one of them was playing around with a wrench,
and hit the plug socket on the back of the CRT, snapping off the end.
The instructor wasn't at all happy with them.
He took them off of the TV set, and handed it off too us more experienced students.
Well, upon looking at the chassis,
those high Schooler's had cut out most of the wiring, resistors, and capacitors!
Luckily we had a schematic of the TV, but that didn't mean it was going to be easy.
It took some three weeks of re-wiring the chassis, replacing components,
and getting the new CRT installed into the set.
Then putting on a cross hatch pattern on it, and doing the purity, and convergence alignments.
We had gotten the set in almost like new condition.
When the set's owner called, and was getting antsy too get his TV back.
But we still hadn't fixed the tuner yet.
Our instructor, knowing that he promised the owner he'd have it ready that day.
Started digging through the shops Old Tuner Bin,
and found a tuner that was identical to the one in the JC Penny Set.
Both tuners were the barrel stye with individual tuned sticks for each channel.
Thus, we took and swapped out the bad channel 2 tuned stick for the good one.
The TV worked great, all channels came in, and it had a great picture.
The owner was pleased to get his set back, and working.
Though, I don't think the instructor told him about it being completely rebuilt.


Signed: Janitor Tzap

[Lenp]

Going back to the B&W days when CRT's had hollow soldered pins instead of the more modern wire pins, cold solder joints were sometimes found, especially for the heater pins because of the larger current.

I had a friend with a set that would dim the picture then it would go off. Some time later, or after a smack on the set top, it would come back.
It was a big console, so I stopped by to look at it and I found that the CRT filament was off but a gentle tap on the socket would restore it.
Ah-Ha, a bad pin connection. In those days they made a crimper that would fix it in a jiff. I crimped the heater pins, and no luck. The problem still persisted. The conclusion was an intermittent in the heater and the CRT would need to be replaced. Yes, there were some guys that tried welding the open filament with a large charged capacitor but it never seemed to be a success either. He decided not to replace the CRT because of the set's age.

Weeks later I stopped in again and he was still watching the same TV. He had rigged a hinge, a small block of wood, a couple of screw eyes and a string so that from across the room, he could thump the back of the CRT and turn it back on. This could have been the original 'remote control'! A long time later the thumping failed and he finally replaced the set but I think I still have the crimper!

Len

[Janitor Tzap]

Yeah,
I saw several of the older sets with heater pin problems.
I'd use my B&K, or the shops Sencore CRT Rejuvenator, and try arc welding the open.
But more times than not, it just made it worse.

Through the VoTech shop I had found a good CRT re-builder that was reasonable.
Wisconsin Tube Factory.{Now Out Of Business}

I was given an old 1968 Zenith 23" color set by a neighbor,
since he knew I was into repairing the old sets.
He told me that he had replaced the CRT on it once already,
but it didn't last no more than a year before it went out.

I looked at the CRT, and quickly knew why it had failed so quickly.
It was a rebuilt CRT that was done by a local guy,
who had a reputation for selling crappy rebuilt CRT's cheap.

The VoTech Shop had many dealings with bad CRT's from that guy before,
and so they stopped getting CRT's from him altogether.
They then went with either Wisconsin Tube Factory,
or a electronics parts dealer that could get factory OEM CRT's.
What was nice about Wisconsin Tube Factory,
is that if you had a one off CRT, or special CRT.
You could send it to them, and they'd rebuild it.
Another thing that was nice about Wisconsin Tube Factory,
was they had a Core exchange policy.
After you got the rebuilt CRT from them.
You then used the shipping container that the rebuilt CRT came in,
to ship the dead CRT back to them.
You then got a check back for the Core.
One thing they stipulated was that the CRT had to be intact with a vacuum still on it.
I didn't understand why, till I got to talking with one of their re-builders.
Simply put, when you snap the nipple off the back of the neck of the tube.
The in rush of air is strong enough to damage the phosphor-coated inner side of the screen of the tube.
Making a blank spot on the screen.

I paid some $85 for the rebuilt CRT, and got $40 back for the Core.
While I had the set all apart.
I checked the power supply, and the large capacitors in it.
Several cap's were leaky, so I replaced them.
Pulled the tuners apart and gave them a good cleaning as well.
After I put it back together, and added a 120VAC muffin fan, too keep it running cooler.
It worked great.
I used it for some ten years, till I replaced it with a 20" Fisher Stereo TV.
I sold the Zenith too some guy for $120.


Signed: Janitor Tzap

[dacflyer]

i used to put larger heatsinks on parts that were hotter then i was comfortable with..
in my book..if you cannot hold onto a heatsink for at least 10 seconds, then its too hot.
i used to salvage lots of heatsinks from other sets or stereo amps etc. i have a box full of them still..some are massive.

[Bob Scott]

i used to put larger heatsinks on parts that were hotter then i was comfortable with..
in my book..if you cannot hold onto a heatsink for at least 10 seconds, then its too hot.

Yup! I call it my rule of thumb ( ) for hot transistors and power ICs.