Ultra 6114 radio 1963

Ultra Electronics has its origins as Edward E. Rosen & Co., which was founded in 1920 by wireless specialist Teddy Rosen. In 1925, a new company was opened, named Ultra Electric Ltd. after a popular commercial loudspeaker that Rosen had developed. It launched various radio-related products during the 1930s, receiving orders from various customers, including the aviation sector. This radio appears to have gold plated fittings, even the VHF telescopic aerial. The gold hasn't kept it's original sheen and there's a faded patch on the leather front, but I've never seen another? so I brought it anyway at a fair price.

The repair

It was a dead as a Dodo, as the old phrase goes, so I stripped it down, two large hex bolts and one Philips bolt in the inside corner hold it all in place. The two hex bolts that double up as rear fixings are slightly different lengths and if fitted the wrong way around will cause the over tightening of the back fixings and breaking of the bolt fixing holes on the inside plastic front. This had happening in my case, the short bolt should be used on the right side. Luckily the broken plastic pieces were in the cabinet and I moulded them back in place with a hot iron. Next I photographed the inside for wiring purposes and un-soldered the speaker and aerial connections, this allows you to completely remove the inside. This protects the leather from being scratched and the wires fraying, but you'll need a spare speaker to test it, unless you extend the wires to the original one.

The design of this set was quit revolutionary for 1963, as getting the extra transistors and IF coils for the FM band takes up quite a bit of extra room, especially in such a small radio as this. The only down point is the failed Mullard AF series transistors. The set has 9 transistors and 5 are the 'AF' type. Don't be frightened of the 4 wires coming from these transistors, the extra wire was just added to earth the metal body. The two center wires are base and earth with collector and emitter either side. The earth is slightly apart from the other wires. Over time the germanium crystals grow in size inside and  eventually touch the metal body and then shorting out the wiring to earth.

One quick test on a dead receiver such as this is to tap each 'AF' transistor on the top with a heavy screwdriver, sometimes if the transistor is shorting the tap will dislodge the crystal from shorting, sometimes it will make a loud crackle and not recover, but this points out the doggy culprit. This I did on this set and nothing happened. I then applied an RF signal (470 kc/s) to the base of each RF stage starting a t the volume control end. When applied to the first general IF transistor, TR3 the radio sprung back to life, so I suspected that transistor, I removed it's earth wire and (hence if it shorts again, it won't be to earth) and the radio has worked fine since. Incidentally the transistors are easy to find on the print side, as they are drawn in a box shape, unlike earlier radios the pins could be anywhere. When removing a transistor or any component us a de-soldering tool (like a small sucker pump) or solder braid to soak up solder.
I've added some service manual information and text form the original service sheet.
General Description:
Nine-transistor (plus four diodes), M.W./L.W./ V.H.F., A.M./F.M. portable receiver. Battery 9 volts (DT6, PP6, T6oo6), no-signal consumption (approximately) A.M. 16 mA., P.M. 19 mA.
Semiconductors: (VT1) AF114; (VT2) AF113; (VT3, 4, 5) A116; (VT6) 0075 or AC156; (VTY) OCS1D or AC11S; (VT8) OC81 or AC154; (VT9) AC128 or AC159 (n-p-n); (W1, 2, 3) OA90; (W4) AA120 (bias stabiliser). Notes: R26 is correctly adjusted when potential of VT8/VT9 emitter junction is 5 volts with respect to positive line. I.F. 470 kc/s., 10-7 Mc/s.
Dismantling:
Remove battery and detach battery lead from wire clamp. Un-screw hexagonal fixing studs (2) and Phillips 4BA screw and washer securing lower right-hand corner of printed board. Note and remove fibre washer located between printed board and fixing bracket. Unsolder lead from tag 5 on tuning gang and also leads from tags 1, 20 and 21, then withdraw printed board assembly from case. When reassembling, do not omit to fit card insulator over loudspeaker magnet.

Transistor that failed for me today (repaired by mod to earth wire)

Some internal labels showing date of cabinet manufacture and battery types, some were loose so I re glued them,

A final touch to the job by giving the band switches and volume control some switch cleaner and too brush to clean controls and she's a rare runner. No doubt if your looking to repair one of these or even have one please let me know as I've never seen another.