Mikeymushradio's HMV 900

[Murphyv310]

        Hi.
I'm writing this from Mike's home in Cramlington. I've been his house guest on Sunday and will head off around 10am to head home. The main purpose was to get The HMV 900 running after the electronics were repaired in 2012. Mike had some problems when the chassis was mated with the cabinet last year. The frame transformer had gone down over that time. So yesterday I connected up the transformer and carried out some other jobs. A few resistors had failed as well. Soon a picture was seen and after David Boynes arrived the sync level was set up we had a brilliant picture. The results are quite amazing considering the dreadful state the set was in when purchased in 2011.

[ppppenguin]

What a lovely result. Looks like a really good CRT.

[Murphyv310]

The tube is superb Jeffrey

[peter scott]

Looking good!

Nice to see a good set develop from a wreck.

Peter

[`FRANK.C]

A really superb result, well done.  
I remember seeing it in 2011 and it was in a terrible state, it would be hard to believe then that it could ever be capable of producing such a brilliant picture.

Frank

[Geordie McBoyne]

Mike's 900 has the best Emiscope 6/6 I've ever seen. We're absolutely delighted with the results. The picture is rock steady. The sync separator is a bit tricky to adjust in these sets, very dependant on the adjusted video level. The two MSP4 sync separator pentodes are conducting during the active picture period and are turned off by the negative going sync pulses. The sync control sets the critical bias level for the valves. Positive going sync pulses are present at the anodes. Having two sync separators is good practise, the results are proven because the interlace is perfect.
It's all the more marvelous when one considers design work on these sets must have began sometime in 1935.

Geordie McBoyne.

[Murphyv310]

Hi.
The odd thing was three resistors had crumbled away in 5 years and the EHT smoothing resistor eventually failed after two hours, I'm sure there could be other small niggles but the result was stunning. the 2.5Mhz bars were resolved and the picture was rock steady with no glitches, jitters or anything.
Mike's face was a picture when it began to spring into life

[Murphyv310]

One thing I forgot to mention was as yet the sound is not connected. The radio chassis has been done but the two have not been tested together.