EMI First Generation Intermittent brightness

[Jac]

Hi David,

If you remove the mid wooden part with the glass and rubber mask attached to it, you can take out the CRT from the top.
See attached pictures.

Jac

[Jac]

About the CRT cowl:

The early 702 and 901 models had a cowl that encloses the CRT almost to the bottom.
Later versions had a large cut-out on the back, so that the deflection coils (and push-about-coil) are accessible.
The old type cowl weighs over 3kg...

Jac

[FERNSEH]

Hi Jac,
My HMV 900 is a very early production model. When I get the chance to dismantle the set I'll take pictures of the CRT housing.

DFWB.

[Jac]

I'm looking forward to that David!

Jac

[FERNSEH]

The attached picture shows the CRT housing of this particular version of the HMV 900. I have in the past attempted to remove the CRT through the aperture without success.

DFWB.

[Jac]

That's interesting David.

Indeed completely different from the "normal" CRT ironwork.
Does it have a similar cover on the back as the later models?

If the hole is too small for the CRT to pass, it must be possible somehow to remove part of the structure.
Isn't it possible to take out the aperture from the top (and separate it from the "normal" ironwork)?

Jac

[FERNSEH]

Originally Posted by Jac

About the CRT cowl:

The early 702 and 901 models had a cowl that encloses the CRT almost to the bottom.

The old type cowl weighs over 3kg...

Hi Jac,
And here it is, it's real heavy engineering stuff. Just check out those welds!

DFWB.

[brianc]

I see your 900 has the Baird TB valve holder in position. Are the extra components in situ too, Dave?

[FERNSEH]

Originally Posted by Jac

That's interesting David.

Indeed completely different from the "normal" CRT ironwork.
Does it have a similar cover on the back as the later models?

If the hole is too small for the CRT to pass, it must be possible somehow to remove part of the structure.
Isn't it possible to take out the aperture from the top (and separate it from the "normal" ironwork)?

Jac

Hi Jac,
The CRT housing is quite different from all the other HMV 900 sets I have come across. However, the rear of the housing does have a removable plate just like other 900 receivers. Some time in future I will tough it out and attempt to remove the tube from the housing, although really there is no need to do this. I just have to prove it can be done, after all someone installed the tube almost eighty years ago.
This is an unusual set. It does not have an HMV emblem, the cabinet is slightly smaller than other 900 TVs. That is if you can use the term "smaller" when discussing these monster sets. Also, the little celluloid ID plate informs us that any correspondence about this "machine" and not the usual term "instrument", the type and serial number must be quoted.

DFWB.

[FERNSEH]

Originally Posted by brianc

I see your 900 has the Baird TB valve holder in position. Are the extra components in situ too, Dave?

Hi Brian,
The set has been converted to 405/50 operation only. Perhaps I should consider refitting the standards switch. All the cableform is still present.

DFWB.

[brianc]

The switch is only a three pole single throw switch! Shouldn't be too hard to find! What sort of toggle should it have?

[FERNSEH]

Hi Brian,
I think the standards switch resembles the on-off switch.

DFWB.