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Vintage Television and Video Vintage television and video equipment, programmes, VCRs etc.

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Old 10th Oct 2019, 5:46 pm   #41
19Seventy7
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Default Re: RRI T24E Chassis

Hi,

Sorry if this is a really stupid question, but what part is the tuning pin? Where do I contact the 2 pins to? I've never worked on tuners before, so don't really know the ins and outs of them. I've looked on the service manual but cannot distinguish the pin.

Would there be a way of getting it to tune into a locked frequency, bypassing the tuner almost? The converter I use allows me to choose frequencies to display using the whole UHF range.

Again, apologies for any silly questions.

Thank you for your help
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Old 11th Oct 2019, 12:52 pm   #42
Welsh Anorak
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Default Re: RRI T24E Chassis

They're reasonable questions.
As you have the manual, have a look at the diagram for the tuner. There will be a variable voltage pin, usually marked VT. Apart from this, there will be a +12V pin (possibly two), an AGC pin and earth. That's more or less it. You need to earth the negative prod of the meter to chassis and connect the other (+) to the pin you think is VT. If you don't know, the 12V pin will stay at 12V and the AGC will be around 5V. The tuning ppin will vary as you select another 'channel' (1-6) on the front of the TV. When you have this voltage, tune the selected button and you should see the voltage vary from less than a volt to around 30V.
If the selector is faulty - possible, but not all that likely - you could use a single variable resistor to put a voltage on the VT pin. However, since a tuner does just that, bypassing it isn't an option, and injecting video later on into a chassis of this type just isn't really a viable option when there are easier alternatives.
Let us know what happens.
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Old 13th Oct 2019, 9:41 pm   #43
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Default Re: RRI T24E Chassis

Hi,

Sorry for the late reply.

I'll get to doing that tomorrow. I'll let you know how I get on.

Thanks for your help
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Old 14th Oct 2019, 7:10 pm   #44
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Default Re: RRI T24E Chassis

For the life of me I cannot find VT on the service manual. I couldn't spend much time with it today either.

What would the tuning pin look like?

Sorry again if it's a stupid question

Thanks
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Old 15th Oct 2019, 12:31 am   #45
toshiba tony
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Default Re: RRI T24E Chassis

Isn't that a T20 or Z718. Unless Rank used the same box throughout their range of sets.
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Old 15th Oct 2019, 8:32 am   #46
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Default Re: RRI T24E Chassis

I think they used the same box for a range of chassis and models. We have an identical looking Bush at the museum with the Toshiba C2290 chassis fitted. It has outstanding performance and has never had the back off, until I took it off since new. John.
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Old 15th Oct 2019, 2:28 pm   #47
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Default Re: RRI T24E Chassis

Yes - it's the same box on the T24. You could tell a Tv was fitted with the T24 because it had never had the back removed...
Back to your question. There are at the most five pins on the tuner. One will be earth, another +12V which only leaves a couple. Trace the wire back to the switchbank and you've got the tuning pin!
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Old 15th Oct 2019, 2:33 pm   #48
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Default Re: RRI T24E Chassis

Quote:
Originally Posted by Welsh Anorak View Post
Yes - it's the same box on the T24. You could tell a Tv was fitted with the T24 because it had never had the back removed...
Back to your question. There are at the most five pins on the tuner. One will be earth, another +12V which only leaves a couple. Trace the wire back to the switchbank and you've got the tuning pin!
Thank you for clearing that up! Ill get to do that ASAP.

Iíll let you know how it goes!

Thank you
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Old 15th Oct 2019, 9:41 pm   #49
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Default Re: RRI T24E Chassis

Wasn't the T24 Toshiba based? True, I never got one in for repair, saw thousands of T20\718 sets. I seem to remember the 718 even to went to schedule three and they were still unreliable. Did like the 18inch version though.
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