1960s vintage 9" GE B & W Portable TV has no Picture

[Captainclock]

Originally Posted by Gregb

I know on my set I had noticed the high voltage lead was all covered with I assume corona dope or something like that. I had measured very low HV and I could hear some arcing but could not see anything. I changed the lead out for some new stuff and the HV came right up to where it was supposed to be and got a nice bright picture.
I also cannot see the filament glow on the 1V2 when in the operation but due to the correct HV I can safely say it is working properly.

Gregb

What kind of wire did you use to replace the HV Lead with? Would regular Heater Cord Wire work? Because I noticed that my HV lead wire has some sort of coating on it as well (some sort of bluish/green crap covering the end of the HV wire lead going to the HV tube socket.)
Also would a replacement coupling capacitor that was too far above the original capacitor's rating cause my issues I'm having? I'm asking because this TV used a coupling capacitor that was a really funky value of .0039 MFD and I replaced it with a .0047 MFD capacitor and the capacitor was rated at +/- 10% and the value I chose to replace that .0039 MFD Capacitor was more than 10% above the original rated capacitor's rating and I'm wondering if I should of maybe left that .0039 MFD cap in place or replaced it with a .0033 MFD Capacitor (which would of been within 10% of the original specs).

[Eric H]

The 1v2 gets it's heater voltage from a winding on the flyback, if the B+ is low then the high voltage is low, hence the heater voltage to the 1V2 will be low.

You have a picture on the screen so the 1V2 is getting enough heater voltage to work, the picture being shrunken and distorted indicates a power supply problem.

Possibly the Selenium Rectifier has gone bad, do you have a volt meter? You will need to start checking voltages, starting with the B+.

When things like this happen it's usually caused by something that got hooked up wrong (been there done that) I would check your work carefully, make sure there are no Solder bridges between circuits.

[Captainclock]

Originally Posted by Eric H

The 1v2 gets it's heater voltage from a winding on the flyback, if the B+ is low then the high voltage is low, hence the heater voltage to the 1V2 will be low.

You have a picture on the screen so the 1V2 is getting enough heater voltage to work, the picture being shrunken and distorted indicates a power supply problem.

Possibly the Selenium Rectifier has gone bad, do you have a volt meter? You will need to start checking voltages, starting with the B+.

OK but I did find a problem that will need to be addressed with the HV wiring, and that is that the connector for the HV wire going into the Picture tube socket is broken so how would I go about repairing that issue? Also Where would I check the B+ voltage at, and would I check the B+ voltage with the set on? And if it is the selenium rectifier that's gone bad what kind of silicon rectifier would I use to replace it with? Would a 1N4007 work? or would I need something different?

[Captainclock]

Well I tested the Selenium Rectifier in both diode mode and with the continuity test mode and it failed both tests so now to figure out what kind of silicone diode to use in place of that old Selenium rectifier.

[Dubis7]

Originally Posted by Captainclock

Well I tested the Selenium Rectifier in both diode mode and with the continuity test mode and it failed both tests so now to figure out what kind of silicone diode to use in place of that old Selenium rectifier.

I've heard 1N4001 is generally more than acceptable.

[Captainclock]

Originally Posted by Dubis7

I've heard 1N4001 is generally more than acceptable.

Service manual shows a 1N1007 which is a germanium type rectifier which I would assume that the silicone equivalent to that would be the 1N4007 but not sure, anyways I'll have to look into the 1N4001 as well. but also I do need to figure out how to repair the HV pin on the picture tube socket because its broken it was apparently previously broken but was being held together in the picture tube socket but then when I went to take the back of the picture tube socket apart to check the HV pin to see if it needed to be cleaned or something and went to pull it out of the retaining hole that's when I figured out that the HV pin socket was broken. any ideas as to how to fix it? would just soldering it back together be good enough?

[MRX37]

Originally Posted by Captainclock

Well I tested the Selenium Rectifier in both diode mode and with the continuity test mode and it failed both tests so now to figure out what kind of silicone diode to use in place of that old Selenium rectifier.

Something i learned on my Sylvana... that rectifier might not be bad.

Here, this post from my thread may be useful to you:
http://www.videokarma.org/showpost.p...5&postcount=83

[tom.j.fla]

Hi, 1N4001 is rated at 50 piv(peak inverse volts) minimum would be 1N4004 rated at 400 piv. ckeck the mouser & allied sites for Belden wire rated for 10 kv, or if you have a color set that non repairable its focus lead if long enough will work as well. On 70 & 90 degree delta gun crts it's on pin 9 & on RCA type inline gun crts on pin 1 tripotenal crts on pin 3 will be wire rated for 15kv. All the best tom.

[Captainclock]

Originally Posted by tom.j.fla

Hi, 1N4001 is rated at 50 piv(peak inverse volts) minimum would be 1N4004 rated at 400 piv. ckeck the mouser & allied sites for Belden wire rated for 10 kv, or if you have a color set that non repairable its focus lead if long enough will work as well. On 70 & 90 degree delta gun crts it's on pin 9 & on RCA type inline gun crts on pin 1 tripotenal crts on pin 3 will be wire rated for 15kv. All the best tom.

OK, well the only issue is that I don't have any TVs that are duds yet... so I may have to check your suggestion about the Belden Wire rated for 10kV.

But the only problem is, I think the wire itself is fine, I think what my problem was, was that my tube socket's HV pin connector was broken and thus had an intermittent connection and so because of that I had low HV and B+ to the picture tube, so I need to figure out a way to fix the said connector.

[Eric H]

Originally Posted by Captainclock

I think what my problem was, was that my tube socket's HV pin connector was broken and thus had an intermittent connection and so because of that I had low HV and B+ to the picture tube, so I need to figure out a way to fix the said connector.

I took a look at a spare chassis I have and it has a CRT socket with a Phenolic cover that is held on with two small screws, if your set uses this type of socket then repairing it is simple, just remove the cover and resolder the wire to the pin. If the used the one piece type socket on yours then you will have to find a way to remove the pin connector and reattach it.

Use great care when plugging and unplugging the socket from the tube, the HV pin on the tube sometimes gets corroded and brittle on these because of the high voltage running through it. A little WD-40 rubbed on the pins can make it slide on & off easier.

[Captainclock]

Originally Posted by Eric H

I took a look at a spare chassis I have and it has a CRT socket with a Phenolic cover that is held on with two small screws, if your set uses this type of socket then repairing it is simple, just remove the cover and resolder the wire to the pin. If the used the one piece type socket on yours then you will have to find a way to remove the pin connector and reattach it.

Use great care when plugging and unplugging the socket from the tube, the HV pin on the tube sometimes gets corroded and brittle on these because of the high voltage running through it. A little WD-40 rubbed on the pins can make it slide on & off easier.

It does have the phoenolic end cap held in place with two small screws which is how I actually discovered that the HV conncetion was broken, which is more than likely why the TV was acting up and wasn't getting the B+ and HV that it was supposed to be getting.

[Electronic M]

Originally Posted by Captainclock

It does have the phoenolic end cap held in place with two small screws which is how I actually discovered that the HV conncetion was broken, which is more than likely why the TV was acting up and wasn't getting the B+ and HV that it was supposed to be getting.

A broken HV connection will only reduce effective HV at the CRT....It should either roughly maintain load on the flyback (perhaps the most power hungry stage in the set) or reduce the load on the flyback. An unloaded fly consumes LESS power so the B+ should either be unaffected or INCREASE slightly (from reduced load) if the HV connection opens like that.....You do realize HV and B+ are two completely separate power sources in a TV right? The power transformer derived or rectified power line derived 150V to 475V B+ found in all tube TV receivers is considered LOW VOLTAGE in TV parlance. The 3KV to 50KV found on the second anode connection of the CRT (usually, but not always flyback derived) is called HV (High Voltage).

You still most likely still have a low B+ issue. If not, then....In most TVs there is also a roughly1000V B+ BOOST rail that is flyback derived (often from the damper in B&W sets, often from it's own diode in color sets).....The BOOST line usually feeds the vertical stage (sometimes CRT screen grid, and other things too).....So if the horizontal is out of whack bad enough to kill or reduce the boost it will affect the vertical, but usually not close to the degree that your screen shots show.

[Captainclock]

Originally Posted by Electronic M

A broken HV connection will only reduce effective HV at the CRT....It should either roughly maintain load on the flyback (perhaps the most power hungry stage in the set) or reduce the load on the flyback. An unloaded fly consumes LESS power so the B+ should either be unaffected or INCREASE slightly (from reduced load) if the HV connection opens like that.....You do realize HV and B+ are two completely separate power sources in a TV right? The power transformer derived or rectified power line derived 150V to 475V B+ found in all tube TV receivers is considered LOW VOLTAGE in TV parlance. The 3KV to 50KV found on the second anode connection of the CRT (usually, but not always flyback derived) is called HV (High Voltage).

You still most likely still have a low B+ issue. If not, then....In most TVs there is also a roughly1000V B+ BOOST rail that is flyback derived (often from the damper in B&W sets, often from it's own diode in color sets).....The BOOST line usually feeds the vertical stage (sometimes CRT screen grid, and other things too).....So if the horizontal is out of whack bad enough to kill or reduce the boost it will affect the vertical, but usually not close to the degree that your screen shots show.

Well I'm not sure if I tested in the right spot for it or not but I had tested the 300MFD 150 Volt power supply capacitor with the TV on to check the B+ voltage and what I got was 147 Volts or so which I'm not sure if that's correct or not because like I said I'm not even sure if that was the correct spot for testing B+ voltage or not but as far as voltage goes for the capacitor itself its still within specs yet (the capacitor in question is a 150 Volt capacitor and it measured 147 under load which is still within specs yet which means that the capacitor is apparently still good yet).

[Electronic M]

Most sets have more than two B+ rails (the lower voltage ones are usually derived from the higher ones with a voltage divider). You need a SCHEMATIC to know where to measure and how much voltage should be at such point....Otherwise you are going to just spin your wheels guessing. Until you (or any would be TV restorer for that matter) have at least 10 tube TV restos under your belt it is usually futile to troubleshoot a set WITHOUT a schematic (even with our help), and even those of us seasoned enough to do most work blind sometimes have check a schematic to know how aspects of a given set should be.

Check with libraries in major cities in your region, and libraries at technical colleges/vocational schools....Odds are one of them has a free sam's library, and for the cost of photocopying you can get the service data. There is such a place 15 minutes from my house (they only keep mid 60's and later sam's), and a more complete library in Milwaukee about a mile from my old College.

147V on a 150V rated cap seems high....If that point is at the doubler and there is a resistor or choke between that cap and the circuits loading the B+, which is going open then it would explain that odd measurement and low B+.....If your set uses a doubler it could also signify the other doubler cap failing.

[Captainclock]

Originally Posted by Electronic M

Most sets have more than two B+ rails (the lower voltage ones are usually derived from the higher ones with a voltage divider). You need a SCHEMATIC to know where to measure and how much voltage should be at such point....Otherwise you are going to just spin your wheels guessing. Until you (or any would be TV restorer for that matter) have at least 10 tube TV restos under your belt it is usually futile to troubleshoot a set WITHOUT a schematic (even with our help), and even those of us seasoned enough to do most work blind sometimes have check a schematic to know how aspects of a given set should be.

Check with libraries in major cities in your region, and libraries at technical colleges/vocational schools....Odds are one of them has a free sam's library, and for the cost of photocopying you can get the service data. There is such a place 15 minutes from my house (they only keep mid 60's and later sam's), and a more complete library in Milwaukee about a mile from my old College.

147V on a 150V rated cap seems high....If that point is at the doubler and there is a resistor or choke between that cap and the circuits loading the B+, which is going open then it would explain that odd measurement and low B+.....If your set uses a doubler it could also signify the other doubler cap failing.

I actually do have a schematic/sam's for this TV that was provided to me by another member here, bu the schematic is split up between 4 pages and I can't see whether or not there's anything about B+ voltage measurements and what they should be, they have tube pin voltage and resistance readings given but nothing for B+ voltage readings. I tried to upload the copy of the Sams I had for this TV but it was too big for me to upload on here.

I saw something about the boost voltage on the schematic and its coming off of the HV transformer and the Boost Voltage is supposed to be 250 Volts, but I'm not sure if that has anything to do with my TV and its issues or not.

Also the Public Libraries near me threw out anything considered old and obsolete (including service manuals, records, audio tapes, video cassette tapes, etc.) years ago so I don't think it would be possible for me to find any Sam's Photofacts in any of the public libraries near me, plus the library system near me is about 30 years old (with most of the library branches being built in the mid to late 1980s) the only library that's old enough to of been able to of held anything like say Service manuals is the main branch of our public library system which is in town and that library's building was built in the 1920s, and it was the only library in Elkhart, Indiana up until the 1980s when they decided to make a city wide library system that featured several different branch buildings located across Elkhart for each township, and then the original library in town was named the main branch of the Elkhart Public Library, and then all of the sub-branches are named after the township or suburb they are located in (e.g. Jefferson Branch, Dunlap Branch, Osolo Branch, etc. and they were all built in the mid to late 1980s so not even old enough to have a sam's or a rider's service manual archive).

So yeah I kind of have to rely on online sources or other people on here for my service manuals that I don't have if I happen to get a project to work on that happens to be covered in a service manual that I don't own a physical copy of.