Apparently a lot of people have been looking for this gem of an eBook and the associated images that were lost in the move to WordPress. The content has now been imported and a new gallery created so this excellent work lives on.
PSEI Trophy-8 has paxolin valve sockets which cause earthing problems for the solder tags, as shown here on the RHS mounting screw sandwiched between the paxolin and the chassis - look carefully!
Marconi CR100 centrally captivated band change cord, which proved extremely difficult to replace. Look carefully to see how the cord enters the little metal drum in two places. It’s very difficult indeed to assemble it correctly.
GEC BRT400K steel dialdrive wire runs in greased brass guides. Early variants (without front panel handles or dial lock) used pulleys. Dial lamps have been removed for clarity.
British Army R209 Mk2 pressure testing set-up, showing the desiccator which has to be temporarily replaced by a purging bung for this operation. When all is well, the manometer shows unchanging pressure after initial pumping.
National NC100XA dialdrive endstop plate shown standing vertically with one bevelled corner visible. This is a very poor design which required careful filing to operate correctly.
KW202 tuning capacitor, showing its non-standard glued plastic cover which considerably reduces VFO drift. Also shown is the Kokusai 455kHz SSB mechanical filter.
Murphy B40D tuning gang, with its fragile ceramic shaft which snaps if the radio has been dropped. This is a scrap set, hence the dead leaf on the LO valve socket!
Racal RA17L filmstrip scale, a thoroughly well engineered solution. Dial bulb removed for clarity. The big disc is the MHz display dial. Its outer knurling bites the dial lock brakeshoe rubber when required.
Murphy B40D needs air to enter this very heavy radio from underneath. The tuning chain can be seen wound round its small drive sprocket which can be seen through the big hole in the casting.
British Army R209 Mk2 desiccator cartridge, with its rubber O-ring seal. Shown with home made pressure testing adaptor which includes the Schrader valve used to prove sealing.
Collins R-390A bellows coupler employed to turn the BFO shaft whilst accommodating squeeze & stretch. At the bottom of this picture are two Sprague Black Tubular (BT) capacitors which must be replaced. To the left of them is a Vitamin-Q which a reliable type.
Hand tools most commonly used by the writer in his own workshop for radio restoration work. Yes, the roll of kitchen towel is there deliberately! The chassis to the left is a Marconi CR100/B28.
Marconi CR100 is a very properly engineered radio which has an ill-deserved reputation for drift and unreliability. The little subchassis standing up to the left of the gang is the noise limiter, with its toggleswitch.
Marconi CR100 showing ceramic pillars used to replace original stud-ended tubular capacitors. A modern polyester capacitor is strapped across the pillar from top to bottom, to replicate the original earthing arrangement.
Marconi CR100 band change shaft is split to allow the flexibility necessary on mid production chassis such as this one. The misalignment is due to a design or manufacturing error which was fixed in late production models.
Marconi CR100 underside view showing absence of BFO cover, discarded at some time due to overcrowding. This chassis has even gaps everywhere: a good layout.
National NC100XA interior view of the catacomb casting. Centre top biscuit removed, to show stator contacts visible through the shaped hole. Rack & pinion drive mechanism to the right of the carriage. Notice the mighty guide bar to the left of the carriage!
Eddystone S358X has a very unreliable single pole mains switch which can fail to break. B40s use the same family of switch: a potential fire & safety hazard.
GEC BRT400 Mk1 IFT carries 240VDC between the RHS (secondary) bobbin and its overwinding, shown here. There is no gap and no meaningful insulation so flashovers are common, especially in damp conditions. Notice the Philips beehive trimmer, a type prone to short circuits. Later BRT400D IFTs had mica fixed capacitors but kept the beehives.
GEC BRT400D with typical decomposing bitumen-impregnated Iron HT components, a very common cosmetic problem on GEC and Philips sets - and also on the RCA AR-8516L.
Marconi CR100 grid caps rewired in 16/0.2mm PVC for the LO (left), and RG316/U PTFE coax cable for the mixer (right). Also shows Hellermann insulating sleeves.
EKCO R1155A original screened cable fitted with a new 16/0.2mm PVC inner, to preserve appearances. The new PVC insulation can be seen next to the grid cap.
This PSEI Trophy-8 uses Meccano chain drive. One example has been seen with a rubber belt instead. Probably the writer’s set was modified at some time.
PSEI Trophy-8 chassis design gives plenty of room to its RF box. Note the retrofit HT fuse mounted by the output transformer, and the new mains cable, fitted by the writer. These modifications are intended to promote safety.
PSEI Trophy-8 general view, showing the cabinet and the unusually tidy chassis topside layout. Notice the huge gold-metallized 6TH8G triode-hexode mixer.
Acorn glass triode which seats into this type of special ceramic socket for the Hallicrafters S36 receiver. Also shown is a later, more advanced 6CW4 nuvistor triode which was in volume production for USA TVs for a couple of years. These were very high technology devices employing ceramic/metal seals.
Eddystone EA12 uses many cheap and nasty components such as these troublesome grey Dubilier resistors. Notice again, the horrible original solder joints.
Lozenge mica capacitors often go leaky. Some American types ooze sticky froth where the leadout wires emerge from the plastic casing when a high DC voltage is applied. This is a sure indication of trouble.
Hunts “Mouldseal” moulded capacitors like these, are extremely inclined to crack open and go leaky or open circuit. The writer’s policy is to replace them on sight!
R-390A mechanical filters from all three manufacturers who made them: Collins, Dittmore-Freimuth and Whitewater Electronics. Some ceramic filters from Clevite were also fitted - not shown here. Beware Collins round-emblem filters which rattle due to rotten foam inside.
British Army R209 Mk2 is a very pleasant small HF receiver which works very well indeed. Design quality was excellent. Production was by MEL o/b/o Philips.
Largely Marconi workshop instrumentation, the most useful being the TF1041C VTVM in the foreground and the two TF144H signal generators. The oscilloscope is a Cossor CDU150. Note the prominent emergency STOP switch.
National NC100XA on the LF band of its coverage. Most of the radio electronic circuits are openly accessible. This side of the chassis is to the original design.
National NC100XA on the HF band of its coverage. This switch position reveals the PSU & AF sections, all non-original due to wiring problems and missing Iron components.
National NC100XA topside view, showing a generally tidy layout using the old style HRO crystal filter. The PSU and audio strip is totally non-original, necessary because of rotten wiring and missing Iron components.
Marconi CR100 operated well under battle conditions as its knobs are large and widely spaced. The RIS connector has been replaced by an S-meter, as is common.
Heathkit SB-300 topside, extremely neat and tidy. This example has three crystal filters, and a full set of six range conversion crystals. There is one compactron. The VFO came from TRW, and is very competent indeed.
KW202 topside, showing lots of wires. The vertical PCB in the foreground is the calibrator, and at rear left is the solid state notch & Q-multiplier board. Notice the writer’s black plastic cover over the VFO capacitor, to reduce drift. Also notice the yellow Kapton tape covering a hole on top of the VFO box. This is directly below the lid finger hole. It stops unwanted rubbish getting into the VFO.
KW202 underside. The two big series resistors feeding the VFO are exactly as fitted originally. Notice how the PCB groundplane is broken up by lots of heater tracking. This causes excessive hum in the audio.
EKCO R1155A with the late dialdrive is a truly excellent receiver, and very light in weight. A previous owner has removed the DF facilities. This example has been much hacked-about over the years, and is typical of most survivors of this model.
EKCO R1155A RF interference trap canister supported only by a small bent Aluminium bracket. It nevertheless proved strong enough to withstand the shock, bump and vibration in a Lancaster bomber aircraft.
Eddystone EA12 variable selectivity. The ¼” shaft carries three cams & levers which change the position of one winding inside each 100kHz IFT. The red Hunts dipped capacitors shown here are usually OK, but beware these grey Dubilier resistors.
Eddystone S770R/1 has some heroic engineering underneath! The antenna trimmer shaft leaves the RF unit at a rakish angle to reach the front panel via two UJs.
Eddystone S770R/1 showing a lot of valves crammed into the space available, a neatly executed design. Inadequate ventilation means this set is a hot runner.
Eddystone S770R/1 RF strip originally fitted with three EF95s, now has a 6AJ5 variable-µ RF amplifier. Selection is needed to choose the right sample because not all 6AJ5s have a suitable transfer characteristic. TungSol examples work fine here.
Eddystone EA12 uses logarithmic compensation of scale linearity. Various covers go over this assembly. Notice the top quality Philips beehive trimmers, which have proper machined leadscrews for a change. The writer wonders why GEC did not use these in the BRT400.
GEC BRT400K has a new loom fitted along the power supply sidewall, shown at the bottom of this photo. The original loom was fried due to shorts somewhere in the bulb wiring, which is a common fault.
GEC BRT400K is a handsome radio but heavy, and the chassis is very inclined to crack and develop other structural failures. Early BRT400s lacked front panel handles and calibrator but went up to 33MHz, and not all late sets had the calibrator.
GEC BRT400K chassis topside view showing a new mains transformer cover. This set started as a BRT402K, and was later given the correct table cabinet to convert it into a BRT400K. Note Kapton tape over the IFT holes, to keep dirt out. Beehive trimmers make this a very sensible precaution. Notice the adaptor plates used to fit B7G valves into chassis holes originally used for B8G types.
GEC BRT400K chassis underside view showing the set as easier to work on than is actually the case. Notice the heavy metal cover over the LO compartment, and also notice the BFO cover at the top right. Equally notice the lack of any proper covers over the aerial, RF amplifier and mixer sections of the bandchange compartment.
GEC BRT400K audio/AGC section is almost the ultimate in valve radio design. In the opinion of this writer only the earlier BRT400D/E was better, care of a posh KT81 beam tetrode output valve rather than a cheaper EL84.
Telefunken E127KW/4 dial is a beautiful piece of work, allowing surprisingly accurate and repeatable frequency readout. Notice the lenticular magnifier.
British Army R209 Mk2 chassis underside shows easy accessibility. The heavily screened box on the left contains the vibrator. The RF box is on the right.
Murphy B40D is a strange-looking but handsome set which is also unusual in its engineering. The massive cast front panel is not as strong as it looks: beware!
Murphy AP100335 is an RN LF + HF receiver designated type 618, designed for smaller vessels. It is very different from the B40, but still unconventional. As yet unrestored. Pye made an inferior direct equivalent to this receiver, selling as the Rees-Mace type CAT.
I am trying to get access to a new band, for Australian Amateurs. Originally a UK band, much of Europe, plus parts of Africa and the Middle East now have it. It will allow experimentation, including with Trans-Equatorial Propagation, as well as being handy during emergencies.
