New Acquisitions

Portable Linesman's Phone (Jun 2019)

 

 

 The above telephone was discovered in an attic and kindly donated by Paul Berry from Burley.Apparently it's a Type 44 for non-military use and the absence of a lid is because it originally came in a leather case.
 

 Wireless Set No.88 (June 2019)

 

  Another early VHF transceiver

Click the picture to read more about this little set

 Wireless Set No.31 (May 2019)

 

 Despite the numbers showing in the dial, this is a VHF FM transceiver and not for use in the HF bands.

Click the picture to read more about this set.

 Andrus SDR (May 2019)

 

 This rather fine looking "Software Defined Radio" was made in Estonia and was designed for reception of radio frequencies from 5KHz to about 32MHz. It's on its way here but I bought it untested at about 20% of its usual price so whether it will work or not I don't know... It was described as "house clearance" and "can't test because I don't have a power supply". A rather risky purchase. Sure enough.. I plugged it into my computer and there wasn't a request for a driver. After a few minutes the case began to get warm so I unplugged it. The next day I removed the circuit board from its case and found that it has three LEDs inside. One lit green and so did the second. Pressing the two buttons "Reset" and "HWBE" caused the second LED to flash three bursts of five which looks to me like an error message? I measured the internal power supply (there are several) One was about 3.3 volts and another 1.8 volts but the other was trying very hard and failing to reach 3.3 volts. I checked and found the circuit drawing too much current and causing the regulator to run exceedingly hot was labelled VCC3V3ETH/AVCC3V3ETH and fed almost exclusively the ethernet controller, a chip labelled KSZ8851SNL. This fed an ethernet socket incorporating two LEDs. I removed this and also a tiny choke feeding the two ETH supplies. Connecting a power supply to the ETH circuit proved it to be consuming 1.5amps at 1.5 volts with the chip running too hot to touch. Maybe someone connected a cable carrying DC (power over network cable) and blew up the chip? The chip is dreadfully difficult to remove and just as tricky to fit a new one. See the picture below..

Without the ETH supplies connected, I plugged in the USB cable and after pressing Reset and HWBE the third LED lit and the computer requested a driver...

click the picture to see its schematic

 

 Although I've swapped lots of surface mounted chips this one will be the trickiest so I've ordered a new rework station. Up to now I've struggled with a normal soldering iron but the so-called QFN package with 32 pins is not going to be easy. It's size is 5mm square x 0.85mm high and the 32 pins are on the underside of the chip. Some QFN chips do not have side access to their pins but this one may because it's defined as a Micrel MLF package. Above, you can see the code number in full (often this isn't the case and you're left puzzling over exactly what it is from the sparse information printed on it). In fact the KSZ8851SNL is no longer made because the KSZ8851SNLI (the version with a wider temperature spec of -40/+85C) has displaced the 0/70C version.

Why did the original fail? As it connects to an ethernet network it might have suffered from a high voltage from lightning or even an experimenter playing around with Power-over-Ethernet. I removed the ethernet socket in case this was responsible for the problem. This is coded TE-6-6605851-1 (click to see the spec) and, because it includes some parts I'll need to check it out for damage before refitting it.

 

 
 The rework station arrived and I detached the faulty chip without any trouble. To see if the chip had been preventing the board from booting up I plugged the board into a USB port. Two green LEDs came on but it was only when I pressed the Reset and HWBE that one of the green LEDs went out and a red one come on that it was detected by the computer (exactly as before). My guess is the ethernet chip is checked by the main processor and failure to respond will prevent completion of bootup.

 

 

 Before fitting the new chip.

As there was a decent quantity of solder present on the pads I didn't add any fresh solder but a good smear of flux was added before applying hot air at around 380C to the board to preheat it especially the solder on the centre pad which I checked was fluid before accurately placing the new chip above its pads.

 

 
 Once the chip was placed in position with its marker dot correctly orientated I continued to apply hot air. At no stage can you see whether it has been soldered correctly as the pads are mostly underneath the chip. After around 10-15 seconds I removed the hot air gun, waited for the board to cool then refitted the ethernet socket which I'd removed for access then refitted the inductor removed to break the short-circuit on the power rail. Just a few spots of flux to remove and the radio looks as good as new...

 Now came the proof of whether (a) the chip has been soldered properly and (b) whether this was the only fault...

The board is powered via a mini-USB lead fitted with two USB plugs for USB3 sockets. Because the SDR program deals only with the Andrus via its ethernet adaptor I also plugged in a patch lead. Plugging in the mini-USB lead made the computer respond which it had failed to do previously. With the ethernet chip removed I had to press the reset button to enable the board from being detected and at this point it couldn't find the right driver. The aerial plugs into the inner BNC socket and then I opened SDR Console and searched for and selected Andrus... whereupon it was detected correctly, and starting the receiver proved all was fine. Radio 4 came in loud and clear with 40m noisy but full of stations.

 

 Here's a couple of screenshots, the second an 80m QSO between G3OQD and G4HJW..
 

 
 

 Measurements Corp. GDO Model 59

 

 

 This old frequency meter arrived today.. 9th May 2019 and looks Hallicrafterish.. It needs a set of coils made to match its dial and at first sight it seems to be a hand-held signal generator covering 2.2 to 420MHz. All will be revealed when I open the case... Yes it's a signal generator and it uses a 955/VT121 triode. This valve was introduced in 1935 and is to be found in several WW2 equipments.

After a little investigation I found the meter part would have plugged into a power supply box, via its cable terminated in an octal plug. The PSU box carried a meter indicating the valve's anode current, making it a grid dip meter.

 

 

 The only maker's mark on the instrument is this logo accompanying the code "SER.748". It looks a bit like an anchor, but I prefer a meter.

The manufacturer was "Measurements Corporation" of Boonton, New Jersey and below are advertisements from 1952 (above) then 1950 (below) depicting the GDO.

 
 

 TS-184A/AP

 

 Above, from 1944 is a piece of test equipment which I was told was used to monitor IFF broadcasts from aircraft. As it's pretty rare I'll need to investigate its pedigree and it's very surprising to see it's survived over 70 years without being canibalised for parts.

 R3673 Receiver

 
 The R3673 forms part of the last version of the GEE system developed during WW2 for accurate bombing. It uses lots of all-glass valves, mainly the EF91 in place of the SP61 or EF50 valves and embodies all the RF and processing circuitry within the same box and is remotely controlled via cabling. See a mention of the system here.

 R210 Receiver

 

 The above aquisition is a prototype of the receiver. Click the picture to see more of it.

 R216 Supply Unit Rectifier No 24

 

 I picked up this power unit for my recently acquired R216 receiver (see below) and will take the place of my home constructed PSU.

 Solartron HT Power Supply

 Similar to this one but a few years newer

 

 LeCroy 9450 Digital Oscilloscope

 

 This rather fine Swiss-made oscilloscope dating from 1990 and the Solartron power supply were given to me by Steven who spotted my old Solartron and thought a second would come in useful. The scope has a fault that's eluded other repairers.

Click the picture to see more.
 
 

 R216 Receiver

 
 

 

I wanted one of these receivers when they first appeared as government surplus but they were too pricey for me. I'd imagined the R216 was just a VHF version of the R206 which I bought in 1958 but of course their design is ten years later (although it does have a turret tuner). When Leighton, GW3FSP advertised his for sale I was first in line and the set arrived here after a week or so.

 

 

 DST100 Communications Receiver

 

 Strowger Relay

click on the picture to see more

 

 Low Voltage Stabilised Power Supply

click the picture to see more

 

 

 Doolittle PR7NA

US Navy receiver made in 1944

click the picture to see more

 

 T4188 Transmitter

These were fitted in the V-bombers

 Click the picture to see more


 A Resistance Bridge made by Elliott Brothers

 A Lissen Kenilworth with push-button tuning

Model 8543

 


 

This has been propped up on our window ledge pointing up the stairs for the best part of 25 years.

Does anyone recognise it?



Toyo 100Watt Dummy Load

 A useful dummy load which turned up recently. I wonder why it's spec starts at only 3.5MHz and what's the significance of "M" and "N" on the curves? This has a PL259 socket so I wonder if "N" implies there's a version with an N connector?

 


 An old REVO electric fan from the early 1930s I think?

 

 

 This came fitted with an old two-pin 2-amp plug commonly used before WW2 and, on the underside, the makers' name "Revo" Model? "12" and Serial Number 62384.

 

It bears a marking for 200 to 220 volts 50 Cycles but etched next to this is "240 volts".

 

I haven't plugged it in because the wiring is a bit too brittle for my liking.

 

I think there are plenty of Electric Fan followers out there so maybe one would care to comment on the Revo's true age?


Sony CDP101

I was tidying up the workshop when I found an old CD player. It was left over from the days I used to repair such things and I recall this particular thing belonged to me rather than a customer. Repairing CD players was a tricky business. Usually one could buy a complete optical mechanism for a few pounds and drop it into place and the player would work like new, however, some manufacturer's models used very unusual optical units whose replacement cost well over a hundred pounds. These equipments were automatically consigned to the scrap heap because prices on new players had dropped to less than £30.

For some reason I'd kept this Sony player and today I looked it up on the Net. It turns out to be the first commercially produced CD player so is definitely worth keeping. These players sold originally for over £500 in 1982 and working models still fetch well over £100.

Ever Ready Portable Radio

See its relation using the same circuit

 A nice Ever Ready portable from 1939. It's a model 5214 and it's most unusual, at least in the UK, as it uses "side contact" valves. These were common in Germany and other places but not the UK, whose manufacturer's preferred octal based valves.

It came from Wimborne in Dorset.

Is the covering real snakeskin? I suspect this may have been cheaper than plastic in those days. Then again I don't recall seeing many red snakes. Perhaps they were wiped out in the late 30s when parted from their outer coverings?


Philips N4418 Open Reel Tape Recorder

 This is the Philips Model N4418, their top of the range open reel tape recorder in the 70s.

I picked it up for £10 from the local recycling centre after filling in numerous forms, presumably to imdemnify the workers, local council officials, the UK Government and Brussels beaurocrats if I accidentally electrocuted myself when plugging it in. Absolute and utter nonsense! What's the world coming to?

Fortunately the mains lead was intact, tucked into a little compartment. Were the recycling people breaking some sort of law not cutting it off!

£10 was a lot of money considering the showroom was not available for demonstrations, but I was very pleasantly surprised when I plugged it in, and switched it on, to find it was in perfect working order.

Even the perspex cover is intact. The only faults I could find were a slipping belt on the tape counter and a faulty bulb in the RH output meter.

Considering that the price of the machine when new was about 50% of a small car such a mini, £10 wasn't bad. As the chap said when he quoted £10, "collectors are after them". Well one was and I'm very pleased I coughed up the cash.


Horn Loudspeaker

 An early horn loudspeaker

Standing on a mahogany base and having a lacquered brass adjuster and connectors, this loudspeaker probably dates to around 1922 or 1923. It was made by S G Brown who were a leading company in the early days of audio amplification, particularly of crystal sets, using magnetic amplifiers, before valves were commonplace.

This example, which has a horn opening of 12" and stands 21" high, appears to have been restored, or at least repainted. The impedance of the energising coil is 4000 ohms and would have been ideal for connection to a crystal set in place of the usual headphones.


Stella ST404T

 Newer than my usual purchases, this Stella "All Transistor" ST404T dates from August 1960. It looks as if it just came out of its box for the first time and worked perfectly when three "AA" batteries were fitted.

 

WW1 Aircraft Transmitter

click the box to see more pictures

 This is part of a WWI Aircraft Transmitter. Encapsulated within the wooden box is a step-up transformer. The metal fittings on the top are parts of a buzzer which interrupts the battery supply. There is an iron stud protruding slightly in the centre of the top panel which is magnetized when current passes through the transformer primary winding. This attracts an iron spring (missing) which carries the current. As the spring moves toward the iron stud the current is broken and the spring returns to its current carrying position, from where the cycle repeats.

The high voltage produced by the transformer secondary winding provides the energising current for the morse code transmitter.

A more complete example (a Trench Transmitter) can be seen here

French Galvanometers

click the picture to see more

 These are two similar examples of a mirror galvanometer, a very sensitive device for use with something like a Wheatstone Bridge.

The greater the sensitivity of current measurement, the greater the accuracy of measurement of resistance for example.

I bought these from a chap in France, where I imagine they were used in a Physics Laboratory. This particular design was invented by a chap named D'Arsonval.

The mirrors are presently detached but normally would be suspended so that they are visible through the front window. A light source can be directed at the mirror, which reflects a spot onto a remote scale. Inside the case is a horse-shoe magnet and the flux from this reacts with the field developed by current passing through a coil mounted with the mirror. The result of this interaction is a mirror deflection.

English Galvanometer

 This is an English galvanometer, probably also from a Physics Laboratory. This type operates as an ordinary moving coil device and has a pointer which deflects when current flows through the instrument.

Both the pair above and this model rely on accurate setting up by altering the height of their feet.

 

Eddystone 770R 19-165MHz click to see

World War I but what is it? click to see

RAF Test Meter

 This meter measures a little over 2 inches across and attracted no interest to buyers, being described as WWII. If it had been correctly identified as WWI, I might have had to pay ten times the sum it went for.

It probably dates to 1917 or 1918, as before then it would have been inscribed "RFC" rather than "RAF".

The case is heavily nickel-plated brass and it reads 0-0.5Amp.

It once lived at the W/T Stores Depot, RAF Kidbrooke in Kent and it has No.4494 marked on the dial.

From the scale marking it could be a hot-wire type of meter and as such could have been used for tuning an early spark transmitter (click to see)

 

Calibrator, Crystal No7 MkI

click to see more


Some old valves

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