GE 14" Safety Question

[Notimetolooz]

Originally Posted by Jon1967us

I have some problems with the CRT tester (B&K 465) and am prioritizing that a bit, replacing some aging components, such as totally open and dry Sprague Atoms, and treating oxidation. The meter is wacked out and quite inaccurate and so I probably need to replace diodes - but thats a topic for another time.

I have a 465. I doubt very much the diodes are a problem. Five of the six are silicon and the sixth is germanium in the meter circuit. Much more likely is the switches and pots, even the cable is a possibility since it is flexed in use.
Hopefully the panel meter itself is OK.

[Electronic M]

Originally Posted by Yamamaya42

getting shocked ( i mean by the HV) is half the fun with old sets like these!

you have not lived until POW-ZAP! your hair is standing on end!

Ooh I've lived plenty...Ever seen the movie office space?...I kinda regard the HV stored in a powered off set like the protagonist regards that staticy doorknob: a necessary annoyance. I hardly even flinch in most screwups...just cus a bit.
The real scary thing to get bit off of is the yoke and the H output top cap of a powered on set...those can supply lethal current, and even if you don't get it across the chest and live to tell they will still char your skin and leave a nasty burn...I have learned that the hard way twice.

When dealing with a powered up set everyone should always keep one hand in a pocket or wear rubber gloves...

[Yamamaya42]

Originally Posted by Electronic M

Ooh I've lived plenty...Ever seen the movie office space?...I kinda regard the HV stored in a powered off set like the protagonist regards that staticy doorknob: a necessary annoyance. I hardly even flinch in most screwups...just cus a bit.
The real scary thing to get bit off of is the yoke and the H output top cap of a powered on set...those can supply lethal current, and even if you don't get it across the chest and live to tell they will still char your skin and leave a nasty burn...I have learned that the hard way twice.

When dealing with a powered up set everyone should always keep one hand in a pocket or wear rubber gloves...

I love the smell of skin burn in the afternoon, it smells like... YUCK!

I remember working on a Zenith hybrid in HS, got a little TOO CLOSE to one of the many electrified metal tabs in it that are sticking up (300v+ or so ), instant automatic reaction was to pull my arm back, this caused the tab to cut in deeper and burn a nice long line on my arm as it went. instantly cauterizing as it went.

Still have the scar.

[Electronic M]

Originally Posted by Yamamaya42

I love the smell of skin burn in the afternoon, it smells like... YUCK!

I remember working on a Zenith hybrid in HS, got a little TOO CLOSE to one of the many electrified metal tabs in it that are sticking up (300v+ or so ), instant automatic reaction was to pull my arm back, this caused the tab to cut in deeper and burn a nice long line on my arm as it went. instantly cauterizing as it went.

Still have the scar.

Ouch! That had to have been a bad day.

Burnt skin is up there with 'strand of hair lands on the soldering iron' in the least appatizing smells working on electronics department.

[old_coot88]

Ever had an RF burn from a transmitter feed line? There's no feel or sensation at all, just the wafting smell of burning hide.

[Tube TV]

I'm not sure about this chassis, but a GE that I have with much the same chassis as this is hot and sits on nylon insulators, and insulated tuner shafts.

All metal parts, chassis, HV cage, tuner are connected to 1 line of the 115 volts ac.
If this is the case with yours also keep this in mind and also check the insulators and take note of the screw lenghts. And check the cabinet with a meter after you reassemble.
Also seing as you're new to tv's, save yourself a great deal of hassle and mark the position of the ion trap on the crt neck with a marking pen before you take it off.

Nice looking set. Best of luck.

[Jon1967us]

Originally Posted by Electronic M

I have done 3 of these sets. You have the early version. Chassis removal is a pain....I think I got the chassis half way out such that I could reach the HV connector on the CRT and discharged it with a probe. I have the Beitmans service manual (a reprint of GE service manual) for the late set and it reccomends crushing defective original caps and resistors on the PCBs and twisting the old and new component leads together and soldering....I have to agree with that approach....the solder side of the PCB is blocked by the chassis and unscrewing the boards to get at the solder side usually destroys the factory board standoff grounds and involves unsoldering several wires...



HV dielectric bounce back!...It is a treacherous bitch. On almost all sets you will get it if you dead short the HV to discharge. The best way to avoid bounce back is to discharge the HV through a resistor 1M or higher....I almost always use my HV probe to discharge and never get zapped when I do....it's always when I cheat and dead short the HV (or neglect to discharge it at all) that I get shocked....

I have no problem with the crushing/J-hook method. I just did some of that on my Philco. I didn't even have to take the chassis out - just worked on the IF board with the back open.

The term "dielectric bounce back" is a new one to me. I didn't know what this was called, however I was observing this phenomenon the other day with a pair of electrolytics, a voltmeter, and test clips with and without a bleed resistor, and sure enough it's the case.

[Jon1967us]

Originally Posted by old_coot88

Ever had an RF burn from a transmitter feed line? There's no feel or sensation at all, just the wafting smell of burning hide.

Negative. I haven't experienced that and I'm an Extra class ham!

[Jon1967us]

Originally Posted by Tube TV

I'm not sure about this chassis, but a GE that I have with much the same chassis as this is hot and sits on nylon insulators, and insulated tuner shafts.

All metal parts, chassis, HV cage, tuner are connected to 1 line of the 115 volts ac.
If this is the case with yours also keep this in mind and also check the insulators and take note of the screw lenghts. And check the cabinet with a meter after you reassemble.
Also seing as you're new to tv's, save yourself a great deal of hassle and mark the position of the ion trap on the crt neck with a marking pen before you take it off.

Nice looking set. Best of luck.

Great advice. Will do!

[old_tv_nut]

https://en.wikipedia.org/wiki/Dielec...y%20discharged.

[Jon1967us]

Originally Posted by Electronic M

Ooh I've lived plenty...Ever seen the movie office space?...I kinda regard the HV stored in a powered off set like the protagonist regards that staticy doorknob: a necessary annoyance. I hardly even flinch in most screwups...just cus a bit.
The real scary thing to get bit off of is the yoke and the H output top cap of a powered on set...those can supply lethal current, and even if you don't get it across the chest and live to tell they will still char your skin and leave a nasty burn...I have learned that the hard way twice.

When dealing with a powered up set everyone should always keep one hand in a pocket or wear rubber gloves...

Yeah man. I hear you loud and clear. I have a healthy respect for the dangers inherent in this hobby. There is a touch of excitement derived from "riding the lightning" that, but rest assured I have no desire to get zapped. I'm trying to do as much homework before getting started, and yes I wear rubber padded gloves, kinda like a mechanic wears, or I have the super rubber gloves.

I've been zapped already from a non discharged CRT once and that time really wasn't too bad. It just felt and sounded like discharging to a doorknob during a dry winter. I've gotten AC zaps off of transformers and chassis countless time, even once across my chest and I definitely dont want to repeat that mistake. I do the one hand in pocket thing.

[Jon1967us]

Originally Posted by Notimetolooz

I have a 465. I doubt very much the diodes are a problem. Five of the six are silicon and the sixth is germanium in the meter circuit. Much more likely is the switches and pots, even the cable is a possibility since it is flexed in use.
Hopefully the panel meter itself is OK.

I missed your post earlier, and you're right, all of the diodes I tested (couldn't find the 5th Silicon) were fine. It was a case of bad electrolytics, dirty pots, and an out of cal meter.

Now it reads fairly accurately.

I'm not sure if the Cutoff test works though. The meter didn't go anywhere on the test, adjusting the G2 knob. Not sure what's going on there...

The CRT on the GE tests fine - low end of 'GOOD' which I think is pretty decent for a 65 YO

[DavGoodlin]

I have the Hotpoint version of this GE and have worked on some others. The WORST discharge I ever got was from a '68 GE color when I was 14, I was running it with the shunt regulator cap off thinking that was intermittent HV cause, and when it did not fix the issue, I leaned over the metal escutcheon to replace the insulated cap onto the 6EJ4, and pow - just like that I was tossed backward. I saw stars!

That view of the PC board brought back memories of being dumbfounded any one would design this way. At least RCA 14" from 56-57 was hand wired, not like PC board sets of 1958 and later, that also required clip and hook replacements.

The CRTS were survivors - 70 degree with a standard tube gun. The first step to take is replace the selenium rectifiers, input doubler cap and the filter caps.

GE tended to use better (still bad by now) wax caps and you may be surprised if you do just the power supply, then fire it up.

I call that a viability test, to see if yoke-fly-crt-vot is OK. The wax caps are still needed, or it won't work for long. That UHF tuner is a definite plus, I never saw one on a GE.

[Jon1967us]

Originally Posted by DavGoodlin

I have the Hotpoint version of this GE and have worked on some others. The WORST discharge I ever got was from a '68 GE color when I was 14, I was running it with the shunt regulator cap off thinking that was intermittent HV cause, and when it did not fix the issue, I leaned over the metal escutcheon to replace the insulated cap onto the 6EJ4, and pow - just like that I was tossed backward. I saw stars!

That view of the PC board brought back memories of being dumbfounded any one would design this way. At least RCA 14" from 56-57 was hand wired, not like PC board sets of 1958 and later, that also required clip and hook replacements.

The CRTS were survivors - 70 degree with a standard tube gun. The first step to take is replace the selenium rectifiers, input doubler cap and the filter caps.

GE tended to use better (still bad by now) wax caps and you may be surprised if you do just the power supply, then fire it up.

I call that a viability test, to see if yoke-fly-crt-vot is OK. The wax caps are still needed, or it won't work for long. That UHF tuner is a definite plus, I never saw one on a GE.

You say you worked on a version of this TV? The one thing I would like to know is if it's possible to power on the set with the CRT outside the chassis, so you don't have to go in and out of the chassis as you're working on it.

[Electronic M]

Originally Posted by Jon1967us

You say you worked on a version of this TV? The one thing I would like to know is if it's possible to power on the set with the CRT outside the chassis, so you don't have to go in and out of the chassis as you're working on it.

It's series heaters so you have to short the heater pins or connect a dummy load resistor of correct value (which you compue the resistance and power of based on the current and voltage spec of the CRT heater on the CRT data sheet.

One option to service this set is to remove both the CRT and chassis from the cabinet then connect the 2 on the bench. If you have a long length of spare HV wire for the HV lead you could extend the HV and yoke leads to reach into the cabinet with the chassis outside the cabinet and use the sets own cabinet and CRT as a test jig for it.... probably good to put any floating HV connections in a glass jar or mug to prevent arcing.