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 Post subject: TELE-TONE Variations Question
PostPosted: Jul Thu 15, 2021 11:20 pm 
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Howdy all knowing TV gurus. I am trying to help a friend restore a TELETONE which has no model number on it. It is very similar to the set showin in SAMS Set 95, folder 6. In fact, the RF/IF chassis appears identical except for one difference. There is an octal socket on the side of the chassis which does not appear to be anywhere in the schematic.

The problem: Got raster, got sound. Brightness works. Contrast control seems to control <ahem> the volume a little bit. No picture, just raster and some scan lines.

I have traced video, with a scope, through to the output of the video amp V8 plate, through to the Sync Sepearator V9. However, no video seems to be getting to the second chassis, which is where the SAMS differs. The actual set has an extra tube (a 6X5) so I do not trust anything on that part of the schematic.

I'm hoping someone might be able to point me to the proper schematic. I've included a few photos of the one of the two chassis in question. I'm wondering if there is supposed to be a jumper plug in that extra octal socket, on the IF chassis (not shown,coming tomorrow).

The photo shows only the deflection/crt chassis, which shows the extra tube that is not in this SAMS, which btw is for a Teletone TV208TV/TV220. The set on the bench does not appear to be this chassis. I'll photo the RF/IF chassis tomorrow, showing the extra octal jack on the side.

Thanks!


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 Post subject: Re: TELE-TONE Variations Question
PostPosted: Jul Fri 16, 2021 1:53 am 
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Your Teletone may be model 208TR, as covered in Riders (Vol. 3?).
The extra octal socket is a test socket and should not have a tube in it. This is not covered in Sams.
Video is connected via a separate wire and pin jack, or via pin 12 of the connecting harness.
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Ron


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 Post subject: Re: TELE-TONE Variations Question
PostPosted: Jul Fri 16, 2021 2:03 am 
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TahoeTV wrote:
Your Teletone may be model 208TR, as covered in Riders (Vol. 3?).
The extra octal socket is a test socket and should not have a tube in it. This is not covered in Sams.
Video is connected via a separate wire and pin jack, or via pin 12 of the connecting harness.
====
Ron


Thanks Ron. I have the sams for the 208TR. The extra octal socket does not have a tube... I wondered if it needs some jumper but will do some more tracing. I just took a 30 minute shot at it today, not enough by far.

The video plug in wire seems to go to the cathode of the CRT, but at the moment has zero video signal on it. I'm going to try checking tomorrow with that lead disconnected. My first question to my buddy was did he check the CRT ... he said he tried another. But didn't check either of them lol. Be great if it's a shorted CRT lol.

Stay tuned. The reason I don't trust the sams is the extra tube on the CRT chassis, which SAMS does not show.

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 Post subject: Re: TELE-TONE Variations Question
PostPosted: Jul Fri 16, 2021 2:28 am 
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Try this Riders. It shows a test socket,
http://www.earlytelevision.org/pdf/tele ... ider_3.pdf

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 Post subject: Re: TELE-TONE Variations Question
PostPosted: Jul Fri 16, 2021 3:44 am 
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Location: Crystal Bay, NV
I don't really know what model you have. Is it actually a Teletone? Teletone made sets for other companies too.

Riders does cover the test socket on the side of the signal chassis, but it does not show the extra 6X5 on the CRT chassis.
It may be a replacement for the selenium rectifier shown on the Sam's schematic.

Sometimes, it is not possible to get an exact match from Sam's or Rider's for a particular set. There were often production changes on the same model number.
Shortages of materials would sometimes dictate a circuit change.

One more thing... If the vertical linearity is not satisfactory, consider replacing those HV ceramics (.005, 5KV). Other types have proven better at maintaining the correct capacitance with wide input voltage swings.
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 Post subject: Re: TELE-TONE Variations Question
PostPosted: Jul Sun 18, 2021 1:54 pm 
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Looks like a new crt


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 Post subject: Re: TELE-TONE Variations Question
PostPosted: Jul Sun 18, 2021 2:05 pm 
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Yes, it is supposedly a new CRT. He had two, one NIB according to him.

I have not gotten back to it yet but first thing is going to be turn off the HV and disconnect the CRT and see if any video is getting to it at all. I suspect not. So stand by :)

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 Post subject: Re: TELE-TONE Variations Question
PostPosted: Jul Mon 26, 2021 3:59 pm 
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Location: Phoenix, Arizona
I had an intermittent problem in one of these sets and found a connection from a tube socket ground to be the cause.

They use tube sockets with a ground post in the center, it grounds through one of the mounting rivets and then a wire is soldered from the post to a punched lug on the chassis.

One single socket didn't have the ground wire and didn't make connection through the rivet.

As I recall there is a test socket on one of the chassis and some versions had one more tube which was a rectifier I believe. thought it was an octal base. The missing tube was a factory design change and as I recall there are other variations from what sams and riders reports.

Those ceramics won't likely work for the vertical, and those electrolytic's look old and could be dried up.

I put a piece of wide masking tape around the test socket and labeled the pins so I could test at will

Jim


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