F. Stephen Masek's HMV468 restoration
 

I'll add more posts to this thread as the restoration progresses.

This radio has been sitting in my garage for too many years. I've now got it on one of my work tables, with the chassis removed. The cabinet front and sides are good enough to save, but not the top, so I may just refinish the top. I'll try.

I bought this at a sale in San Diego at the home of a deceased collector. Somebody did some work on it, but most components appear to be original. A Marconi model seems to have the same chassis.

https://i269.photobucket.com/albums/...ssis%20out.jpg

https://i269.photobucket.com/albums/...as%20found.jpg

Re: F. Stephen Masek's HMV468 restoration
 

It is finally on my work table. The schematics I have show a resistor in series with the field coil, but this radio was built with another choke in series with the field coil. It is original, as it supports the terminal board for the cable to the speaker.

The two large Bakelite blocks for resistors and capacitors under the chassis are also different that what is shown for the Marconi models.

It would be nice to have a schematic for this radio, but I will probably have to draw it by modifying the Marconi schematic.

The choke and terminal board (I untied the wires to trace the circuits)
https://i269.photobucket.com/albums/...028_085645.jpg

The main power fuse, an unusual (to me) yellow thing
https://i269.photobucket.com/albums/...028_085657.jpg

Re: F. Stephen Masek's HMV468 restoration
 

Hi
Unless I am mistaken the yellow thing is a heat coil protector that I saw used to protect strowger switches on 50 volt exchanges. As the coil in the device heats up with excess current through the coil the solder holding the pin in melts and the spring in the mount pulls the pin out of the body.
Regards
Ian

Re: F. Stephen Masek's HMV468 restoration
 

Somewhat like a fire sprinkler in which a link holding a plug in place melts.

It would be nice to find a schematic for this model, but it may not exist.

Re: F. Stephen Masek's HMV468 restoration
 

It seems closer to the HMV 467 Model, as it has a tapped field coil with one end grounded, and two chokes in the power supply.

It has a fuse between the center tap of the high voltage winding and ground, a nice feature to prevent destruction of the power transformer.

Re: F. Stephen Masek's HMV468 restoration
 

I've made good progress. The capacitor block is rebuilt and ready to re-install. I stripped the cabinet today, revealing very nice wood grain on the front, and a water mark on the top, probably from a houseplant. I'll use wood bleach, and stain the top and sides to obtain an even color. The Marconiphone 276 schematic is the closest I have found to this model.



The capacitor block out and the top with the terminals removed
https://i269.photobucket.com/albums/...16%20small.jpg

The rebuilt capacitor block. I cut away unneeded parts of the can. I noticed that one corner of the can had shorted to a wire going to the rectifier tube. That edge is now gone, and I've patched that wire.
https://i269.photobucket.com/albums/...00%20small.jpg

I am grateful that the water damage on the top is not bad.
https://i269.photobucket.com/albums/...10%20small.jpg

The original grille cloth is made with red, olive green and gold yarn or thread.
https://i269.photobucket.com/albums/...26%20small.jpg

I saved the best for last in this post. Look at that beautiful veneer on the front which was hidden under the darkened and deteriorated old finish.
https://i269.photobucket.com/albums/...32%20small.jpg

Re: F. Stephen Masek's HMV468 restoration
 

The chassis mounting arrangement. I will have the red rubber pieces re-made.

Re: F. Stephen Masek's HMV468 restoration
 

Very impressed with the work so far. It's a shame that the clock ( being designed for 50hz mains in the UK0 won't be accurate on your 60 hz.

Ian

Re: F. Stephen Masek's HMV468 restoration
 

I will find a way to operate the clock. It does not need much current, so some sort of relatively simple converter should be possible. Perhaps I will return the radio to Europe, perhaps to the flat Rima and I own in Vilnius, Lithuania.

Re: F. Stephen Masek's HMV468 restoration
 

It is alive, at least from the 3rd valve through to the speaker. I was able to connect a signal generator to the grid of the 3rd valve and heard the 400Hz tone in the speaker. It had a VP4A in the 3rd position, instead of a VMS4B. I tried switching the VMS4B in the 1st position into the 3rd position, with the same result. That tells me both valves work, at least somewhat. The MH4 oscillator becomes warm, but I've not yet determined if it is oscillating.

Re: F. Stephen Masek's HMV468 restoration
 

I'm finally back to working on it!

The cabinet with vinyl sealer applied. I had first cleaned away the shellac I'd previously applied, as the cabinet was too dark, and there were some runs where the stain and shellac had mixed.

https://i269.photobucket.com/albums/...ll%20image.jpg

The water damage on the top will be mostly hidden by the new HMV water-slide decal. I thought about replacing the top veneer, and decided the risk of damaging the side veneer was too great.

https://i269.photobucket.com/albums/...ll%20image.jpg

The cabinet after the first coat of clear gloss lacquer
https://i269.photobucket.com/albums/...ll%20image.jpg

Re: F. Stephen Masek's HMV468 restoration
 

I sprayed some Deoxit D5 on the band switch assembly today, then worked it for several minutes. That was quite helpful. The radio is still weak, but I've got no idea about the condition of the valves, and one of them is missing all of the spray-applied shield. I'll probably take the radio to Europe, where the clock will work properly (Rima and I have a second home there).

Re: F. Stephen Masek's HMV468 restoration
 

Playing, with the old valves of unknown quality I have. I'll try to rig a way to test them.

Re: F. Stephen Masek's HMV468 restoration
 

That cabinet looks very good to me.

Re: F. Stephen Masek's HMV468 restoration
 

Hello,

This looks interesting but what’s the story? I’d love to know why you are keen on this particular set, what it means to you to be doing this so mindfully and I get a sense of almost protectiveness towards it.

Shame about the externally-hosted photos , they’re really slow to upload. Can you upload them onto the site , very easy to do ?

Also , are you the restorer ? It’s confusing ; I assume you’re referring to yourself in the third person for some reason? I’ve never come across that before

Re: F. Stephen Masek's HMV468 restoration
 

I just like it, and it was obviously a top of the line model when new.

This is the way I do all of my restorations. Some others do far more and have far more experience and skill. It is a fun hobby, and it is still fun to hear them play, often for the first time in many, many years. To see more of the ones I've restored, just search Antiqueradios.com for threads with FStephenMasek in the titles, or look at my Photobucket Library.

I bought it at an auction of the collection of a San Diego, California, USA collector who had died.

Where did I use 3rd person? Not that I can see, unless it is a typo somewhere.

Re: F. Stephen Masek's HMV468 restoration
 

Oh it says FStsphenMasek’s restoration of a ... ‘, and you are FStephenMasek.

I’ve only ever see another person make someone in the 3rd person ...

Re: F. Stephen Masek's HMV468 restoration
 

The cabinet is coming along nicely. This is with the first coats of clear lacquer, the new top decal (from a maker in Peru!) and dark brown toned lacquer on the base trim (Mohawk M104-2060 Dark Sapele Brown). I will wet sand it, then spray the final coats of clear gloss Mohawk lacquer.

I wonder who owned this radio before me? It seems likely that they listened to all of the events of WWII on it. and who know what else before it somehow got to San Diego.

https://i269.photobucket.com/albums/...ed%20small.jpg

Success with an HMV468
 

I finally found a wiring error. I took care to label each wire to the capacitor block, but it may have been my error. Someone else had worked on it, so perhaps I bought it that way. Who cares, it sounds great now! Since it is a British radio, I decided to connect a CD player to the Phono. input and play a Londonbeat CD. It sounds nice indeed. The error had the bottom of the inter-stage transformer secondary connected to the center tap of the cathode/filament resistor of the PX4 output valve.

The best schematics for this radio are those for the HMV Superhet Concert 7 in the Music Seller Circuit Disgram Supplement dated September 1933, and the one for the Marconiphone Model 276 in the Service Engineer Supplement to The Broadcaster dated July, 1935. Note that the schematic for the Marconiphone 176 has the part designations for the left resistors flipped - R10 is where they show R10, and vice-versa.

Somebody (not me) closed my thread on this radio, so please search to find more information. I now need to align the radio, then install the components, including the clock, in the cabinet.

Here it is playing, and a section of the schematic:

Re: Success with an HMV468
 

Nice work detecting the error in the wiring!

How are you running it with your 110v supply? A British radio normally runs at 240v - 50 hz.

SEAN