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Old 14th Mar 2021, 4:47 pm   #261
Helder Crespo
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Default Re: My first telly TV22

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Originally Posted by Travellingwave View Post
I see from earlier in the post that to increase the width I need to add capacitance - so I should be able to put some capacitance in parallel with the existing to find the right amount - so I can tag onto lopt topside , saves me messing about under the chassis till I find the right value and put it in properly.

Better get some ordered.
I guess you could get/use cheaper 1000V-rated ceramic caps to find the right value (it's a good idea to tag them onto the lopt topside to test) and then order a dipped silver mica as final.
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Old 14th Mar 2021, 6:49 pm   #262
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Default Re: My first telly TV22

I’ve just connected a raspberry pi via composite video to the hedgehog and played a video clip. Getting quite a lot of buzzing on the sound , seems less when the video is on full screen mode. Not sure if it’s vision on sound , but if I unplug the audio inputs to the hedgehog it does reduce which tends to suggest it might be coming from the rasp pi
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Old 14th Mar 2021, 8:33 pm   #263
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Default Re: My first telly TV22

If your powering the Pi from a switch mode power supply it could be filtering through.
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Old 15th Mar 2021, 9:29 am   #264
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Default Re: My first telly TV22

Thanks Freya It’s powers from a raspberry pi wall wart which I assume will be a smps will try with a dvd
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Old 19th Mar 2021, 8:53 pm   #265
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Default Re: My first telly TV22

I got a 240 pf mica 1000v cap. Ended up buying from the US as the Usual UK suppliers were asking ridiculous postage for a £2 component of only selling in lots of 100.

Anyway I recon it’s added a couple of cm to the width , could do with a bit more but probably ok

Might have another go at waking up my nos PL81 see if that helps

Is there likely to be any issues waking it up in circuit - ie if the line output doesn’t start up properly?
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Old 19th Mar 2021, 8:55 pm   #266
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Default Re: My first telly TV22

Also got an HDMI to composite converter which should give a few options for sources
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Old 19th Mar 2021, 9:55 pm   #267
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Default Re: My first telly TV22

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Also got an HDMI to composite converter which should give a few options for sources
I got one of those too, but ended up not using it much. My main source is a cheap freeview box with composite output (eBay) which also plays most video formats from a USB stick.
I'm glad you managed to increase the width with the new cap. In my case, 240pF would have been too much, but this of course depends on the actual capacitance of a particular rewind. Have you tried to play videos from sources other than your raspberry pi with the noisy ps? I'm still curious about how it handles actual content as the scene brightness changes.
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Old 19th Mar 2021, 9:58 pm   #268
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Default Re: My first telly TV22

Quote:
Originally Posted by Travellingwave View Post
I got a 240 pf mica 1000v cap. Ended up buying from the US as the Usual UK suppliers were asking ridiculous postage for a £2 component of only selling in lots of 100.

Anyway I recon it’s added a couple of cm to the width , could do with a bit more but probably ok

Might have another go at waking up my nos PL81 see if that helps

Is there likely to be any issues waking it up in circuit - ie if the line output doesn’t start up properly?
Have you adjusted/optimised C28 (on the Mk2 trader sheet)?
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Old 20th Mar 2021, 10:44 am   #269
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Default Re: My first telly TV22

Tried adjusting c28 it had a very small effect. I put back in the nos PL81 , this time it’s fired up but width is even lower and not a very bright picture with a lot of size change when brightness is adjusted. I’m leaving it switched on for a while to see if The new valve wakes up a bit more
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Old 20th Mar 2021, 10:45 am   #270
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Default Re: My first telly TV22

What does the trimmer cap on the deflection coil adjust?
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Old 20th Mar 2021, 11:08 am   #271
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Default Re: My first telly TV22

New valve has woken up nicely and I recon I’m back to where it was before the Lopt rewind
Pic 1 before
Pic2 after
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Old 20th Mar 2021, 11:25 am   #272
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Default Re: My first telly TV22

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What does the trimmer cap on the deflection coil adjust?
visually, it minimizes the fast intensity variations (vertical lines) on the left side of the image
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Old 20th Mar 2021, 11:39 am   #273
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Default Re: My first telly TV22

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New valve has woken up nicely and I recon I’m back to where it was before the Lopt rewind
Pic 1 before
Pic2 after
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Old 20th Mar 2021, 1:47 pm   #274
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Default Re: My first telly TV22

I have hooked a fire stick via HDMI to composite converter to the hedgehog and it seems to work ok. Get a bit of interference from the WiFi but nothing too bad. Picture seems stable enough to me . I have taken a video and will post on YouTube later.
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Old 20th Mar 2021, 1:50 pm   #275
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Default Re: My first telly TV22

I never replaced the mains filter cap which might be why I’m getting a bit of breakthrough as I’m using a power line WiFi extender to get a signal to my garage
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Old 20th Mar 2021, 5:41 pm   #276
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Default Re: My first telly TV22

I have uploaded a video to youtube of the set working with some real content

link below

https://youtu.be/2RSYF-1usEA
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Old 20th Mar 2021, 6:41 pm   #277
Helder Crespo
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Default Re: My first telly TV22

Quote:
Originally Posted by Travellingwave View Post
I have uploaded a video to youtube of the set working with some real content

link below

https://youtu.be/2RSYF-1usEA
Thanks! Nice scene from The King's Speech, with the Battersea power station art-deco control room posing as the BBC HQ
Looks great, with perhaps some sound on vision. You can try to minimise this by adjusting/slightly detuning the oscillator coil (L5, I think). I don't know what the possible wifi interference (via mains) would look like though. Are you getting good interlacing? From the image there seems to be at least some line pairing, which is normal in the TV22 anyway.
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Old 20th Mar 2021, 6:45 pm   #278
Helder Crespo
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Default Re: My first telly TV22

Quote:
Originally Posted by Travellingwave View Post
I have uploaded a video to youtube of the set working with some real content

link below

https://youtu.be/2RSYF-1usEA
Sorry, I don't think there's much sound on vision after all. There's some intermittent noise / glitch, but this does not seem to be correlated to sound.
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Old 20th Mar 2021, 6:53 pm   #279
Helder Crespo
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Default Re: My first telly TV22

Quote:
Originally Posted by Travellingwave View Post
I have uploaded a video to youtube of the set working with some real content

link below

https://youtu.be/2RSYF-1usEA
I coudln't detect any change in image size with scene brightness. Your set seems perfect in this respect. I guess the NOS PL81 really made a difference here (after waking up).
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Old 20th Mar 2021, 7:11 pm   #280
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Default Re: My first telly TV22

Hi Helder

I'm pretty sure the glitching/noise is coming from the wifi range extender - its one that uses the mains wiring in the house to transmit the wifi signal - and I can see that the noise correlates to the network traffic light flashing on the range extender, I suppose it adds a bit of realism as though the signal was coming off air.

Its quite interesting to watch the same You tube clip on the computer/modern tv v the old 405 line set - the 405 seems sharper to me somehow.
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