Sound Sales - a not so short story......

[PJC58-Hythe]

Sound Sales - a not so short story......

I bought a Sound Sales Set for £10 and decided it would make a good project as there aren't many about and not much is known about them. Little did I know what I was letting myself in for!

To start with it was in a far worse condition than the pictures had originally portrayed. Secondly I discovered there is virtually no service data for these sets, and to make matters worse I had one that no one seemed to be able to identify. The nearest was a Schools 'Special Six' but that one did not have the tuning indicator. There was only one thing for it, take lots of pictures, trace out the circuit and produce my own service data! This proved a little more difficult than I first imagined as the first two valves were impossible to identify, the metal coating having deteriorated badly and the markings impossible to see. Then I remembered a tip my Dad once gave me about applying a very small quantity of water on a rag to the coatings and bingo! I could read the faint writing X61M and W61.

Once I had the circuit finalized and the data made up in a document I set about stripping down the set. All I can say is this set must have been labour intensive to build as there are so many screws and nuts! I first removed the front panel dial and lamps, then the associated tuning mechanism along with the volume pot and mains switch. I drilled out the rivets holding in the valve bases then un-soldered the transformers, choke and the smoothing capacitors, and removed these. I then removed all the screws and nuts holding in the metalwork under the chassis and withdrew the shafts for the wave change and radio/gram switches. I was then able to remove all the remaining components plus valve bases along with the metalwork from the bottom of the chassis.

The chassis, case, transformer casings and front panel were in such a bad way due to rust I had to get them grit blasted. Once this was done I then spent literally hours sanding down the chassis in order to paint it. The front panel (as you can see) has a polished metal ring around the tuning dial but after coming back from grit blasting it was pitted and definitely not shiny! Several hours more with a Dremel grinder plus various grades of wet & dry from 200 - 600 and finally metal polish I had it back to it’s original state. The metalwork dividers under the chassis weren’t too bad and I prepared these without the aid of grit basting. An unexpected advantage of having the case grit blasted and lightly sanded afterwards was that I could just spray it black and it looked very close to the original crinkle effect without the need for the crinkle paint.

The dial had a domed plastic cover which was completely shot and needed to be replaced. Fortunately I know someone who works with plastics and he was able to produce me one from a mould which he used for something else. Otherwise I would have scrapped the set - producing a mould is a costly business. The dial itself could not be cleaned without removing the lettering so I took some high quality pictures of the lettering and used software on the computer to produce a good black and white image suitable for printing back on the dial. Once I had completely cleaned off the paint (the dial is made of brass!) and re-sprayed it antique white I used a self-adhesive transfer to reapply the lettering and then over sprayed with a durable varnish.

I decided to replace all the caps with the exception of the very low value ones in the RF section and the 4uF 400V one in the smoothing section as that seemed OK. Surprisingly all the resistors were within tolerance. I then set about reconstructing the re-sprayed under chassis metalwork with the components attached. I tested the output transformer, choke and mains transformer and discovered to my horror the mains transformer was open circuit primary and VERY leaky between windings. This meant I had to find someone who could either produce a replica or rewind the original. Problem was I didn’t have the voltages for the HT-0-HT but luckily I found someone on the Internet who had a working Special Six with the same valve line up and who was happy to measure the AC voltage off load for me – Thanks Mike! I managed to find a small company not too far from me who were extremely patient and more than helpful (http://www.transformers.uk.com). While they could produce an almost exact replica it didn't quite have the same footprint as the original. Cut a long story short they agreed to rewind on the original bobbin provided I came up with the winding details. So….. one rainy I day stripped down the transformer laminations, counted the turns on each winding (HT was 1821T of 30swg!) took loads of pictures and kept a sample of the wire from each winding. I presented them with the bobbin, the sample wires and a pair of laminations (which are UT rather than EI) and they rewound on the original bobbin. I then reassembled the laminations and the casing and I was back on track again.

I then set about re-assembly of the rest of the set starting with the transformers, tuning capacitor, rectifier base, smoothing choke and the 4uF capacitor. Then I assembled all the under chassis metalwork and components separately. Once I had this complete I then lowered the whole lot into the Chassis along with the valve bases then riveted them in. I then inserted the switch spindles and bolted everything together. Once the underside was complete I set about the rest of the set finally finishing with the front panel. I then attached a loudspeaker and powered the set up. After checking a few voltages I attached a short wire to the aerial socket and was rewarded with a fully working set on both MW & LW. I did some spot checks on various frequencies to make sure there hadn’t been a ‘phantom fiddler’ and everything seems to be spot on. I have a small amount of residual hum that needs to be tracked down but it’s only noticeable with no signal so I’m not too worried about that. For the moment I’m happy enjoying the set, the sound quality of this set is truly amazing. Just need to put it back in its case now.

I hope you have enjoyed this ‘not so short’ restoration and hope it will spur you on to tackle things that look beyond redemption!

[PJC58-Hythe]

Some more Pictures....

[mark pirate]

You have done A fantastic job, a real labour of love
How bad was the case? I am doing my first cabinet rebuild at the moment, give me the electronics anyday!

Mark

[neil29]

What a transformation. i know ive said it before and ill say it again. that is i wish i had the patience to do such a thorough restoration. top job . cheers neil.

[Andrewausfa]

That's excellent, glad you got this sorted I really do admire the work you put into your restorations, like your Murphy earlier this year, way beyond what I'd even dream of attempting.

Andrew

[Herald1360]

Impressed!

Sounds like full marks to Majestic for customer service, too.

[PJC58-Hythe]

For anyone that's interested I have attached the Circuit diagram with corrections found during the rebuild.

[PJC58-Hythe]

Thanks for the comments Mark - The case was just as bad as the chassis! Fourtunately it's metal so it was sand blasted and has been sprayed black, but I'm not happy with the finish so it will be done again (hence no pictures yet). See the attached picture just after primar had been applied.

[PJC58-Hythe]

Chris thanks for the positive comments. I cannot stress how helpful Majestic were, it's refreshing to find a company with old fashoined values in this day and age!

[Tim]

Wow! Thats what I call a restoration.

[IJK2008]

Truly amazing! You must be very pleased with the outcome.

Ian