Ultra U930 Minstrel

[Jim - G4MEZ]

An account of my first real restoration and the cause of me catching the old radio bug all over again...

This seems a quite a rare one if searching the web is anything to go by. It's an attractive little bakelite table model with a white plastic grille and is one of the very early VHF sets. Mine is dated 30th June 1955 by way of a date scratched on the inside of the case.

It has been in my family for longer than I can remember. My last memory of it working was when I was a young boy and seeing it sat on a shelf above my dads lathe in his workshop. That was about 1972 and I recall it being very decrepit then with no VHF reception and little in the way of AM reception. I had completely forgotten about it until I found it languishing in a corner of my dads loft about 10 months ago, covered in dust and cobwebs.

It did not look promising on first inspection. One section of the dropper had (and still is) been bridged with an RS Dropper Section and the UCC85 was missing. After a good clean-up it did not look half as bad as it did.

I gave it a good check over electrically, and it seemed OK, the smooting block was not looking stressed and an AVO across it showed it to still have some capacitance and little leakage. Not having the luxury of a variac or a lamp box I fired it up with a meter hanging across the HT line. I watched the valves light and watched carefully as HT began to come up. As soon as about half HT had come up, I switched off and watched it fall slowly. I repeated this about 10 times, letting the HT get a bit higher each time until finally I was happy nothing was being stressed and the HT would not rise any further although it was a bit low.

As in 1972 it was lifeless on VHF and nearly so on AM, just picking up a bit of QRM from all the PCs running in my workshop. Most of the problems turned out to be O/C Hunts Mouldseals and after replacing a few of them around the Mixer and IF amp life was restored on VHF very nicely. It had slightly distorted audio which I put down to a weak UY41 causing a low HT voltage. In searching for a replacement UY41 I stumbled on some NOS UY42s at a very good price so I bought two and put one into service. A slight improvement.

After a really good clean-up of everything the set looked really great, Electrolube CTC on the bakelite case brought it up like new and it really shines. CTC on the white speaker grille did a great job and the true beauty of the case came shining out, it really is, I think, one of the prettiest sets of the 1950's. I also replaced a few more suspect capacitors and a few resistors that had gone off-spec. Performance was then really good except for the slight distortion. People commented on the "tone" as they do..

I have used it since that day as my workshop radio where it does sterling service 5 days a week for 8 or 9 hours at a time. Sometimes it would even get left on overnight and once over a weekend . After it's thirty or so year rest it was now getting well used .

One evening I was browsing around the web and discovered to my horror that a UY42 was not a good replacement for the UY41, being rated at only 110V. No wonder they were cheap! I read of the dire consequences that would befall any set using it that ran from 240V Mains. The hunt was on for a UY41 or two and the usual source came to the rescue, along with a brace of UL41s. I got a replacement UY41 in as soon as I could given the hard life the set was now leading.

Slowly, the distortion got worse. I checked and found the control grid of the UL41 was a bit positive despite replacing the (good) grid coupling capacitor. Another UL41 cured that. I reckon the old one was suffering the leaky base syndrome and one day when I'm bored I'll try the "zapping" method of fixing it and see if it works. Strangely, when switched on from cold there was little distortion but progressively it would get worse over about 45 minutes.

The set continues to give sterling performance to this day. On at 7am and off when the last person leaves for the day, day in day out. Not bad for such a venerable old set.

VHF performance is excellent. I leave the back off so that it does not deteriorate from the heat generated by the Dropper, UL41 and UY41 and thus use a length of wire as an aerial strung around a metal framed window with metallic film on it. The walls of my workshop are metal so effectively it is working inside a metal box. A while ago I acquired a Bush VHF81 and thought I'd replace the Ultra with the Bush but I found that the Bush VHF performance was rubbish compared to the Ultra. I could not receive a good signal on the Bush despite its FM performance being bang up to spec. It could not handle all the QRM generated by the PCs running in close proximity so the Ultra remains in service, doing a sterling job.

What an excellent little radio. I recommend to anyone to save and cherish one if they ever come across one. It's my favourite, even over my VHF64!!

Jim

[Paul Stenning]

An excellent first restoration.

Originally Posted by G4MEZ

Strangely, when switched on from cold there was little distortion but progressively it would get worse over about 45 minutes.

That's fairly usual. I guess the problem gets worse as the valve warms up, though I'm no expert on the inner workings of valves.

A while ago I acquired a Bush VHF81 and thought I'd replace the Ultra with the Bush but I found that the Bush VHF performance was rubbish compared to the Ultra. I could not receive a good signal on the Bush despite its FM performance being bang up to spec. It could not handle all the QRM generated by the PCs running in close proximity so the Ultra remains in service, doing a sterling job.

I suspect your VHF81 may need some further attention as these usually work very well (though the internal VHF aerial isn't much use). However you have a workshop radio now that was also a workshop radio 30 years ago, so why replace it!