1945 ambassador 545 ac/dc

[David Simpson]

Folks, I've had a shufti through "Search", but can just find a 2014 thread about a mains Radiogram version. Nor can I find yet a circuit diagram. Nothing in the BVWS Trader Sheets CD's, nor in my old Molloy & Pool books. Just a brief bit of info on "Radiomuseum". Seemingly a mixture of 12V & 35V heater valves.
Made by R.N.Fitton Ltd of Brighouse, Yorkshire.
Any advice most appreciated, please.

Regards, David

[Boater Sam]

Its a fairly common American Octal valve lineup, a set with similar valves should be a circuit that you could use.

Try Amplion Delegate HU610

[David Simpson]

Well, I've eventually found some circuit diagrams & brief info. The Radiomuseum site has pictures & no circuit diagram, but with AC/DC valve info.
Then the radio-workshop.co site just has a c/d + info for the 545H AC only version, as does an old Molloy & Pool ref book I've found. That also tells me that there were 3 versions of valve line-up for the AC/DC sets, Brimar, Ferranti & Mullard. This one has :- V1 = Brimar 12K8GT, V2 = Brimar 12K7GT, V3 = Brimar 12Q7GT, V4 = (poor lettering) C13(?)something, V5 = Brimar 35Z4GT. The 545H mains version has all 4V valves, seemingly.
I guess this is a "Brimar" version.
However, it would still be handy to get an AC/DC Circuit Diagram. The M & P book also says that the AC/DC version should have a "Brimistor" fitted in the heater circuit.

Regards, David

[David Simpson]

Finished at last. There are, I suspect , at least 3 versions of this model. The 545H which is a mains only version. And possibly two versions of the 545 :- a UK/Pan European AC/DC version, and a Middle/Far Eastern AC/DC version.
This one I've been working on, plus the gash/damaged donor(see the "Any Ambassador Experts ?" thread in the Cabinet Restoration sub-forum) have three frequency ranges :- 1 = 550 to 1800 KHz, 11 = 1.75 to 6 MHz, 111 = 13 to 49 MHz. On the dial glass, for ranges 1(MW) & 11(SW), only middle & Far Eastern Stations are listed, and the higher short wave band 111 does list quite a few world-wide stations. So they appear to me as export models. Great reception on all bands from late afternoon through to late at night on all bands using my 80m Doublet antenna. But struggles during the day except for Radio Scotland & a couple of Scottish Commercial stations on MW. After much blading-off of grotty varnish, much sanding with several grades of sandpaper/emery cloth, 2 coats of normal mahogany wood stain on the top & sides, and 4 coats of dark mahogany on the front, progress was made. Followed by 4 spray coats of acrylic clear varnish all round. Then a dark polish of the front, & a clear polish of the top & sides. The brown bakelite front surround cleaned up well with Farecla G10 paste, and the decent dial glass came from the donor.
Some lengths of wire with perished insulation were changed, plus a couple of capacitors that were leaking. The ON/OFF switch was moved from the Neutral i/p line to the live.
It has the same valve line-up as the Ferranti 546, and similar AC/DC circuitry.
Many thanks to Duncan Leece for the donor.

Regards, David

.

[DuncanLeece]

Well done Dave. Great to see the set brought back to life, and I know its owner will be delighted by your kindness in doing it. Also glad my scrap set came in handy.
You wonder in your cabinet thread about how the veneer came to be detaching so badly from the scrap cabinet? It came in a batch of sets I bought for parts; they were from various makers and all in similar condition, so it must be down to some very poor storage. But yes, I have rarely seen the like, and the chassis seemed fine!
The decent and highly original Ambassador 545 I have, works very well too, from what I remember. Given they are not one of the more common makes, there do seem to be a strange number of them here in Northeast Scotland, and it may well just come down to having been a particularly good dealer locally, and of course the desire of the fisher and maritime families to have sets with Trawler Band back in the 1950s, which I am sure I remember my model has.
Once again, well done.
Best wishes
Duncan

[David Simpson]

Thanks for the kind words Duncan. Fact is, folks, if Duncan hadn't donated the phooked 545, I would have seriously struggled. In yesterday's photos you'll see the donor's cabinet in the background with numerous trial patches of different colours of woodstain & varnish on the front. Trying to get close to the original finish was a nightmare. Quite frankly, I'm an inexperienced novice when it comes to Woodie restoration. Duncan & our chum Steve are advanced experts in that field, with fantastic valuable collections.
Needless to say, I wont be chomping at the bit to attempt another veneered cabinet sometime soon.
I know its a contentious issue, but I tend to steer away from AC/DC sets. Yes, one can repair them & get them working jolly well. But having an earlier military background & a later electrical inspection background, I feel that safety -wise, they are best just used as display items these days. When I return this set to its owner(it was his grandfather's), despite all my safety tests, it will be the caveat that if he does switch it on it should be via a wee modern plug-in RCD. My home & workshop is on a PME supply with everything protected by a main 30mA RCD, plus modern MCB'd Consumer Unit. But as for the premises of other folk we do jobbies for, albeit as a free favour, who knows how well protected they are, electricity-wise.

Regards, David