View Single Post
Old 11th Dec 2018, 8:30 am   #24
Catkins
Pentode
 
Catkins's Avatar
 
Join Date: Feb 2015
Location: Chepstow, Monmouthshire, UK.
Posts: 234
Default Re: 1938 Murphy A56V television restoration

Quote:
Originally Posted by peter_scott View Post
Great write-up. Thanks for posting.
Thanks Peter.

I have now got my HMV 900 out of storage and I can now give you the model numbers.

Sod's law means I had already packed it away when you asked for the model numbers. I didn't expect it to be over three years before I got chance to look at it again (my excuse is I only have space to have one set under restoration at any one time).

I have begun a preliminary check of the chassis and compared it against the descriptions elsewhere. Is anyone keeping tabs on the extent of Baird circuity present in these first generation sets? I see there's recording of whether the Baird valve is top-blanked or bottom blanked, but there appears to be quite a few differences between top blanked sets. Some have the socket top blanked and nothing left whatsoever of the other circuitry. Some have more than that. I saw one thread with photographs that showed it had almost the complete Baird circuitry surviving bar the standards switch.

Further reading suggests the difference is often between EMI modified sets and dealer modified sets. EMI did the complete overhaul whereas dealers often did no more than necessary, remove the switch, blank the socket.

Is that your understanding of the situation? Does anyone care about this?

This HMV 900 seems to have more Baird circuitry present than anything else I have seen. From what I can tell it is complete bar the standards switch.

Regards

Catkins
Catkins is offline