GE 9T001. Hotpoint 9S101 - retrace lines
 

I have a GE 9T001. and a Hotpoint 9S101 TV, both have retrace lines.
What causes this ... solutions ?

Thanks,
JerryR

Brightness set too high, heater to cathode short in picture tube, vertical problems. So many possibilities. Can you give more specific info and maybe a screen picture of symptoms?

Jerry:

The primary cause of retrace lines in that TV is the absence of a blanking circuit. The CRT control grid returns directly to ground. It needs a 25 to 35 volt negative pulse to cut off the CRT during vertical retrace. When everything in that TV is working, there is little to spare so there's no place to get the negative vertical pulse without upsetting something else. The vertical output plate goes positive, the cathode is grounded, the B+ feed has nothing to spare so it leaves the oscillator plate. That's 60 v p/p, but at very high impedance so bleeding some off for blanking will reduce the vertical size and upset the oscillator timing. Look over some other GE portable designs of the era and you will see blanking schemes that could not be used on the 9" TV. I suspect the blanking circuit was the subject of a few engineering meetings with product planning. Finance eventually won out. It was a cost compromise and justified as a differentiator and a reason to step the customer up to the 14". That TV eventually cost GE a bundle. It sold for $99 and was quietly recalled to replace every 9QP4 CRT. Off-on-volume controls were another recurring problem.

It would require a design effort using a transistor or two to isolate the CRT blanking network from the other circuitry. The chassis design and PC layout leave little heat-free room for additional components. In short, it is expected to have retrace lines as designed.

Don

Why were the CRTs recalled? I have seen that set and it looks like a direct competitor to the 8" RCA portable of the time. The RCA was the better set as it was hand wired and all metal. The GE/Hotpoint used PC boards and plastic front mask and trim if I remember correctly.

GE replaced the CRTs due to early failure rates. It was a new CRT design using a low wattage heater, light weight glass and a single ended connector. There is no separate anode connection. Within a few months of operation many experienced bad picture tubes and bad off-on switches. Many of the CRTs listed on ebay are the duds.
GE wasn't too particular about getting all the bad tubes back so some were stored around TV shops for years. New GE replacement tubes should have a blue monogram on the very end of the tube connector and a number-matching warranty card.

The 8" RCA was a better basic design with a power transformer, conventional tubes and more B+. It had poor sensitivity and early vertical problems. Both had 2 video IFs, but RCA had 1 IF in the tuner and had to skimp on the tuner gain as well to keep it to two tubes. The 9" GE used a conventional Oak tuner.

About the same time, Admiral made a rectangular 10' that was much better. Unfortunately, it suffered from bad tuner design.

Don

Sensitivity is not great on the RCA. On a weak signal, the contrast drops off. It is still I think one of the best of the Fifties metal portables.

So is there any hope for these two TV's I have?

JerryR

I have a picture of the Hotpoint screen here, how do I post it?
JerryR

reduce you pic size to less than 200k (or less than 900x900) whichever is less. Then at the bottom of the thread where you normally post a reply, click "Go Advanced"

After you have done that, you will see a button labeled "Manage attachments" at the bottom of the page. Click it to bring up a window that will allow you to upload your file. When your done, click the "submit reply" Button.

Alternately you can post the IMG code if you are hosting the picture on an image serivice (photobucket, imageshare, imageshack, etc...) Most of those sites have a code generator if you are unfamiliar with the syntax.

Here's a picture of the Hotpoint screen guys.
JerryR

Jerry:

That looks like video trouble or a defective CRT. Does the brightness or contrast affect the picture? Are you able to get a watchable picture with a good antenna?

Don

If the brightness control has no effect, then the picture tube likely has a heater to cathode short which might be cleared with a rejuvenator.

You can also use a crt filament isolation transformer (looks like a "booster" but is for isolation only) if you have an h-k short.

Yes the brightness or contrast affect the picture - I'm getting audio, I'm just using a set of rabbit ears at this time. Would our outdoor antenna be better?
JerryR

Hi Jerry,

The set should produce a good pic with few/no retrace lines in under most conditions.

It definitely needs a strong signal, i checked one of my sets and as soon as the signal drops off the retrace lines pop up, the switch next to the antenna terminals is a local/distant switch, it should be set to distant if you're in a weak signal area.

Also the brightness needs to be kept low.

You didn't mention if you've done any work to these sets?
Usually replacing the capacitors is the minimum they will need to work right, also the horiz afc double diode is always bad on these (it's Selenium but can be replaced with two ordinary Silicone diodes)

Wonder if GE will still honor the CRT recall and replace my CRT? :D
This set is using a rejuvenated tube.
(The pic looks better than the actual picture on the set!)

Eric

Jerry:

See what it does with an outdoor antenna or cable. Can you get a picture like the one in Eric's example?

Did I understand that you have two of these TVs? If so, compare performance. If they both perform about equal, that may be as good as it gets. These TVs were most popular in metro areas served by VHF channels. There was very little UHF and the transmit audio channel was operated at higher power. It was intended as a second TV for use in the kitchen or childs room and not as the family TV.

I tried both TV's with an outdoor TV antenna @25'. The GE 9T001 has audio with what seems like about 3 retrace lines. The Hotpoint 9S101 has no audio but still retrace lines. The GE has some cap work done to it. I have a Precision CRT tester that I can test the picture tubes with. I haven't checked the vacuum tubes on either set. I'm also working on a Sentinel TV-400, just began recapping it, I happen to have an extra 7JP4 for it. Any additional suggestions appreciated.

Thanks,

JerryR

Jerry:

I am not clear on the symptoms. Does either one have a decent picture with the antenna connected? Does the horizontal hold affect the picture?

Be careful teating those 9QP4 picture tubes. They operate on a 4 volt filament voltage at 300 ma. Make sure you set the filament voltage before connecting to a tester.

Don

Neither set has a decent picture with the antenna connected. The horizontal hold doesn't seem to make any difference.
How do I go about setting the filament voltage --- ?
(Be careful teating those 9QP4 picture tubes. They operate on a 4 volt filament voltage at 300 ma. Make sure you set the filament voltage before connecting to a tester).

Thanks,

JerryR

Jerry:

You must use a CRT tester with variable filament voltage. The later Sencore and B&K testers have adjustable filament voltage. If your tester is an early type with fixed 6.3 volt filament setting, I urge you not to try it. Otherwise, if your tester instructions list a 9QP4 then it should be OK after it is set up for that tube.

Don

Don,
my Precision CR-30 CRT tester has a filament voltage selector switch, it ranges from 2.5 to 25 volts. Thanks for the info, more later ......

JerryR

Bear with me guys, as this is the first CRT I've tested with the CR-30 tester. I have the connector on the CRT socket, the directions say to connect the alligator clip that's on the connector to the HV anode terminal on the side of the tube. I don't see one on the 9QP4, do I have to remove the CRT to see it? Is the 9PQ4 a metal cone type CRT?

JerryR

The 9QP4 doesn't have the anode on the side, it's in the base of the tube, the pin that's all by itself. I don't know if your tester has to have this connection or not, the B&K's don't.

I doubt your tube is bad, it seems plenty bright so the emissions are good, it could have other problems but those are rare and the fact that both sets are doing the same thing seems more likely to be a video problem.

I have three of these sets in working condition but none of them worked as found, recapping was needed to get them going. The CRT's in all of mine had various problems too, one is weak (rejuved), one had a broken HV anode wire (patched up) and the other just seems to be a poor quality rebuilt tube (dim).

Theres barely $10 worth of caps in this set and an hours time once you have it apart. I would start with that and see where you are.

...

OK Don and everyone, thanks for the help, looks as if I'll be replacing caps for my winter project here. I post results after the holidays.

JerryR

Jerry:

I recommend troubleshooting the symptoms first to avoid building in more problems before finding the original one. If the caps have already been replaced, make sure they are installed properly.

Did the TV ever work for you? If so, I would diagnose the problem before doing a wholesale changeout. It should work again with very few component changes. Once working, replacing caps may cure heat related problems, distorted audio, loss of control functions, sync drift...etc.

Check the video coupling caps first. They are the ones in the grid and plate circuit of the video amp. Also check the video detector diode. Check plate, cathode and screen voltages on the video output and CRT. Do the appropriate tube voltages vary with contrast and brightness control settings?

Don

GE 9T001. Hotpoint 9S101, FOR SALE ? I'm not sure that I will have the time to work on these two TV's. Anyone interested in either, both, or parts? Please e-mail me.
Thanks,

Jerry
[email protected]

GE 9T001. Hotpoint 9S101, FOR SALE
 

GE 9T001. Hotpoint 9S101, FOR SALE ? I'm not sure that I will have the time to work on these two TV's. Anyone interested in either, both, or parts? Please e-mail me.
Thanks,

Jerry
[email protected]

Ge 9t001
 

Hey Folks, Pete here. Got this neat little T.V. - GE 9" TV Model 9T001/2 - and I am in need of the centering ring assembly for the yoke or maybe it just slides on the neck of the tube with springs, I don't know. I spent about four days cleaning the goop out of it. Recapped most of it and did a double restore on the pix tube and it is working rather well, considering. Now all I need to do is get the pix centered and it's good to go ! ! ! Any help and/or suggestions from you folks would be a great help. Pete . . God Bless . . . . [email protected]
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