Bush Tv22 Help needed!

[slidertogrid]

Hi,
I have been working on a Bush TV22, my first TV restoration, I followed the Radiocraft restoration, but did not strip the LOPT.
After cleaning the chassis I recapped the set and powered up, the Ht was very low but the set came to life and I had a dim raster.
After running the set for a while the Ht fell to 100v and the EY51 went out.
after a few checks I concluded the ht side of the pz30 was probably clapped so I disconnected the ac into the valve holder and lashed up a temporary ht supply using a series resistor and a silicon rectifier, I left the line stage part of the pz30 connected as original.
I now have a fairly bright raster and intent to buy a standards converter as soon as funds allow.
Sorry to go on! Here is the bit that puzzles me, I connected a wire to the aerial socket and by tuning L5 which I assume is the band 1 tuning I can pick up fm radio! I can get radio 4 radio 2 and a couple of others, the contrast control acts as a sort of gain control and the sound goes into bursts of oscillation if the control is turned fully up.
The raster can be made to flicker and roll with the hold control there doesn't seem to be any modulation on the screen and the brightness control seems to have little effect.
The Lower deck differs from the trader circuit in that the trader sheet shows EF80 s and my set uses EF91 s which are smaller, the same size as the EB91 s If I put my hand near v2 I get a increase in volume.
So, what have I done wrong!? I can post some pictures if needed the set is easily accessible as it currently resides on my dining room table!
My other question concerns a 405 signal, until I can afford a converter if i get a kind person to do me a vhs tape of 405 how do I connect the video machine to the set, do I buy a vhf modulator and then connect video and audio out from the machine to the modulator and then into the set?
If so any hints on where to get a modulator?
I am starting to feel a little out of my depth, and there is a limit to how long I can get away with it being in its current location!
Any help gratefully received !
Rich.

[yagosaga]

Hi,

Originally Posted by slidertogrid

Sorry to go on! Here is the bit that puzzles me, I connected a wire to the aerial socket and by tuning L5 which I assume is the band 1 tuning I can pick up fm radio! I can get radio 4 radio 2 and a couple of others, the contrast control acts as a sort of gain control and the sound goes into bursts of oscillation if the control is turned fully up. ...
The Lower deck differs from the trader circuit in that the trader sheet shows EF80 s and my set uses EF91 s which are smaller, the same size as the EB91 s If I put my hand near v2 I get a increase in volume.
So, what have I done wrong!? ... My other question concerns a 405 signal, until I can afford a converter if i get a kind person to do me a vhs tape of 405 how do I connect the video machine to the set, do I buy a vhf modulator and then connect video and audio out from the machine to the modulator and then into the set? If so any hints on where to get a modulator?
I am starting to feel a little out of my depth, and there is a limit to how long I can get away with it being in its current location!
Any help gratefully received !
Rich.

You did nothing wrong. The receiving of FM stations is possible with the Bush TV22. I can also receive FM with detuning L5.

You should try to get a new PZ30.

A good 405 standard converter is the Aurora converter, offered by Darryl Hock:

http://converter.home.comcast.net/~converter/

The Early Television Foundation also offers a 405 modulator:

http://www.earlytelevision.org/405_modulator.html

Kind regards,
Eckhard

[murphyv310]

Originally Posted by yagosaga

Hi,



You did nothing wrong. The receiving of FM stations is possible with the Bush TV22. I can also receive FM with detuning L5.


http://www.earlytelevision.org/405_modulator.html

Kind regards,
Eckhard

Hi.
Well done I dont think you have any great problems. If you are in a good signal area for FM tuning L5 high up will give you Radio reception, and if you see disturbance on the screen that would confirm the video stages are OK.
Personally I would get a PZ30 ASAP as these sets do take a while to heat up so the HT can be unloaded for quite a while prior to the set drawing current.
The aurora is the best solution both a standards converter and modulator combined and a good price.
Well done and i'm sure the bug has bitten.
Trevor

[Steve_P]

Agreed. Get a new PZ30 and a Modulator and try it. You will get FM radio by retuning L5 - FM radio is about twice FM so it will come in. Ignore it!

Please try and clean up the lopt though, for reliability.

Cheers,

Steve P.

[slidertogrid]

Thanks all for the quick reply s I am still puzzled by how it picks up fm though, I always thought 405 sound was am, or am I wrong?
Anyone able to explain it to me (in fairly simple terms)!
I have kept a close eye on the lopt and it runs cool at the moment, true it has no cans over it and the set is not in its cabinet.
I am really scared of damaging it by trying to remove the pitch, I changed the Ey51 and the heater connections looks very fragile !
The screen has a faint patch in the centre I don't know if this is a slight ion burn of if it will get any better with use, I will try to post a picture.
Thanks all for your encouragement, I shall get myself a Aurora as soon as possible.
Rich.

[Steve_P]

It's probably what's called Slope Demodulation. If you have an FM signal, it does not in theory very in amplitude. But, the IF of an AM demodulator will be sloped. If the FM is off frequency, the slope will turn the FM into AM, which is then demodulated.

Cheers,

Steve P.

[slidertogrid]

Thanks Steve, That sort of makes sense to me I knew I should have paid more attention at Tech collage!
Some pictures of what I have so far, please excuse the smoother lash up, it is only temporary until i get the correct capacitors to rebuild the original can.
The mark on the screen can just about be seen.
Rich.

[Steve_P]

Looks OK to me but do the can and get a PZ30 before you try powering it again. Safety first!

Cheers,

Steve P.

[FRANK.C]

Originally Posted by slidertogrid

The Lower deck differs from the trader circuit in that the trader sheet shows EF80 s and my set uses EF91 s which are smaller,

There are a few different versions of the lower deck on the TV22. The version with EF91’s is available on the Vintage T.V. Service Data CD. I believe that the type fitted with EF91 is of earlier production than the EF80 type.

Frank

[Steve_P]

This is therefore a Bush TV22A. Trader Sheet 1130.

Cheers,

Steve P.

[Ian - G4JQT]

Hi Rich,

The breakthrough of FM is not unusual and is slope detected as described. It seems to go away when properly tuned in to a band I TV signal.

From your photograph I think yours is a TV22 MkI if it has EF91 valves on the lower (RF/IF) chassis. The MkII uses EF80 valves here and has some other differences in the RF/IF section.

The TV22 A has an almost identical RF/IF chassis to the MkII, but the video/audio is quite different with the line output transformer mounted horizontally with alternative focussing arrangements and other differences.

Bush TV22/TV24:
Mk I Trader sheet 1003/T15
Mk II Trader sheet 1091/T38
Type A Trader sheet 1130/T50

I have worked on a few. Lovely sets when operating well, but patience is needed when setting up the picture for optimum results.

Regards,

Ian

[slidertogrid]

Thanks all for your help and advice.
I bought a rectifier from e-bay, restuffed the smoother and removed my lash ups The set seems to run better with the valve fitted although the HT is much the same, the frame linearity seems better and the brightness range appears wider ??!
I am going to try the set on a friends Domino soon so I will see how much more there is to do!
Not wishing to drift off topic here but he has a fairly large Tv collection and has given me permission to take some pictures
Rich.

[slidertogrid]

I took the Tv22 to my mates workshop today and tried it on his converter, after finding the brightness control to be o/c and wiring in a temporary replacement a fairly good picture was at last on the screen
The set has never had a Itv converter fitted so this is probably the first picture in 40 years!
The off air picture is nice and stable but the test card is recorded on video tape and the set objects to this and gives a shaky picture, is there a "video mod" for the Tv22?
Result though, I expected more problems than just a knackered brightness pot!
The old telly bug has bitten!

Rich

[Tazman1966]

Originally Posted by slidertogrid

The old telly bug has bitten!

Well done Rich I reckon that'll be the first of many

Cheers,

[Steve_P]

Have a look around V7. Check R28, R29 and R30. Poss R33.

Cheers,

Steve P.

[Michael Maurice]

Originally Posted by slidertogrid

The off air picture is nice and stable but the test card is recorded on video tape and the set objects to this and gives a shaky picture, is there a "video mod" for the Tv22?

The old telly bug has bitten!

Rich

Playback of video recordings was always a bug bear of a lot of early TV's right up to the late 1970's, you would have to modify the flywheel sync. Personally if off air transmissions work, either don't play back video recordings or invest in a digital timebase corrector.