Saba Meersburg Automatic 6-D
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Tim Norman from
Ampthill very kindly dropped off this rather fine radio which
he'd found in his loft. From the label it's certainly a German
import.. maybe brought back to the UK in the late 1950s or early
1960s by a National Service conscript? I hadn't realised it had
a motor tuning feature which must have made it an expensive proposition.
Our Murphy family radio from the late
1930s had an auto-tune feature but it wasn't fitted in our example.
click
the radio above to see its circuit diagram |
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Canadian 52 Set ZE12
Power Supply
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Purchased March 2022,
this is the matching power supply for my 52 Set
Click to
see more |
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CJD ELF/VLF Receiver
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R1355
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I bought this because
it looks reasonably complete (except missing the outer case and
painted in an odd blue and yellow colours).
When these receivers came onto
the government surplus market in the 1950s they were advertised
as being admirably suited for modification to serve as IF amplifiers
for home brew TV sets. They are rarely seen in an unmodified
state. This example has a mains power supply and strangely, a
new set of components.
The chassis is fitted with an
RF24 marked with numbers 1-5 which could relate to Band I Channels
1 to 5 except the RF unit tuned to lower frequencies as shown
below. For TV use an RF25 would be better but I can see through
ventilation holes the RF24 has also been fitted with new components..
so has it also been modified for Band I reception?
What confuses me though.. the
components are really new.. too new for Band I TV.. so what's
its purpose?
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Channel |
Vision MHz |
Sound MHz |
RF24 MHz |
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1 |
45.00 |
41.50 |
22.0 |
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2 |
51.75 |
48.25 |
22.9 |
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3 |
56.75 |
53.25 |
25.3 |
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4 |
61.75 |
58.25 |
27.3 |
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5 |
66.75 |
63.25 |
29.7 |
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Click the picture to read more
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Mystery RAF Radio
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I couldn't resist
buying this WW2-vintage receiver as I've never seen one before.
It turned out to be quite interesting as it's actually a Bendix
MN26-C Radio Compass. From what little information I've found
these cover 100KHz to 1500KHz in three wavebands so would make
a very good domestic radio, which is how the government surplus
market handled them. This example has been modified for use as
a domestic radio, rather than the alternative advertised use
as a car radio, but still maintaining its remote tuning gearbox
but with lots of extra knobs and switches dating from the same
era as the set. On the top of the case it carries an RAF crown
and what looks like the code 10D/401**.
When I have time, I'll open
it up and see why it's so incredibly heavy. Originally it was
packed full of IO based valves and a dynamotor for 28 volts DC.
That dial carries only 0-100 and could do with a good clean.
Click the
radio to see more |
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**Below, the only external
markings, slightly indistict which Alf, G3WSD has decoded as
"110D/401".
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Teac AG-D200
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Not an ancient collectable
radio, but a replacement for my ageing Teac
Receiver/Amplifier which has started to give me a headache.
Things started to go wrong when electrolytic capacitors in its
low voltage power supply circuits began to fail. Then dry joints
started to make their presence felt, and then something inside
started to get very hot causing it to cut out. Hours with a soldering
iron, then the addition of a computer fan running from the amplifier's
internal 12 volt supply (via a resistor to limit the voltage
and hence fan speed an acoustic noise) fixed the problems, but
not long afterwards the thing would fail to deliver any sound
unless thumped very hard on its top. Time to replace the whole
thing... and I spotted this much newer Teac being sold with a
"staticky" fault. Hopefully I can fix this and then
perhaps spend time to correct failings on my AG-15D? The new-looking
remote control only responded to a few of its buttons so I took
it apart and found lots of syrupy deposits on the circuit board.
Considering the circuit board is covered by a rubber layer carrying
moulded buttons it's puzzling as to how liquid got under the
layer of rubber, but careful cleaning restored 100% of its commands. |
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The equipment seems
to work OK but I looked on the Net for a repair manualand had
no luck. I can find an operators' manual but not that for repair.
Interestingly, I must have triggered a response because I now
get advertising blurb for a new example of the AG-D200... at
a whopping £349.99 plus £6.99 postage (opposite).
My outlay of £35 for a crackly version seems pretty good!
I plugged it in and sure enough I could hear faint crackling
on radio reception. The front feet slipped off the front of the
bench and the thing bumped down half an inch. I slid it back
into place on the bench and the crackles had completely stopped
so it looks like an embrionic dry joint or could it just have
been poor radio reception?.... I'll lift off its covers and try
and spot it. Let's hope it's more repairman friendly than the
difficult- to-dismantle AG-10D...
PS. It's just as awkward to
take apart as the old model and waggling everything in sight
wouldn't make it crackle, although one of the side speaker outputs
was quieter than the other and the display is a bit dim. |
Hello Allan Isaacs,
Based on your recent activity, we thought you might
be interested in this.
TEAC-AG-D200-7.1-Channel Home Cinema Receiver.PROFESSIONAL.4X
HDMI INPUTS
by Teac
Price: £349.99
Dispatched from and sold by D**** (UK). |
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A magic meter that can seemingly
test anything.
Click it to read more. |
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Voxon bass fifty amplifier
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This old amplifier was donated
by Alan Phillips, a visitor to the Radio Museum carrying duff
lift circuit boards needing attention. I'd previously shown
Alan my rebuilt Moreton Cheyney amplifier
when he said he'd got something similar. It was only later I
lifted it onto the workbench when I realised it was indeed similar
because of its immense weight and having removed the rear cover
and noticed the two hefty transformers.. Those output valves
are Pinnacle-branded EL34s, and the name "fifty" maybe
implies 50 watts output? |
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The valves are a mixed bunch.
The EL34s are Pinnacle and a Mullard with the two smaller audio
valves both ECC83, again a Pinnacle and a Mullard. The rectifier
valve is an EZ80, presumably for the EL34 anodes and on the right,
under the chassis, is a selenium rectifier for the ECC83s. There's
also a pair of silicon rectifier diodes.. maybe for the EL34
bias supply? Or the other way round as I haven't checked the
circuit details.
As you can see below, from the printing
on the mains selector panel (missing its shorting plug), the
amplifier post dates the Radiospares change to "RS"
in 1971 but my Hi-Fi year books are silent on the Voxon name..
at least in 1972/76/ 79. |
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Below a view under the
amplifier chassis and then a view from the top. Most of the parts
seem to have been sourced from RS. The mains transformer appears
to have a date in November 1966 and the output transformer is
marked 15 ohms and "785-80" (possibly an RS stock number?). |
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Audition Instruments Pre-amp/Reverb unit
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Above...this preamp which
came with the Voxon, at first looked like it came from the same
manufacturer but when I looked inside it was completely different.
It uses a couple of printed circuit boards marked "CDK TP-15A
and TP-15B" and Toshiba transistors. From the crude build
quality it looks British***. The badge states "Audition
Instruments" but I can find no record of this nor the Voxon
amplifier, although "Voxson" does appear mis-spelled
as "Voxon" in a few places.. |
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*** You can see the construction
in the pictures below. When I attempted to detach the chassis
from the case after removing securing screws it wouldn't budge.
I used a screwdiver as a lever and forced it out. The self-tapping
screws holding the lower circuit board were far too long and
prevented the chassis sliding into the case so it had been jammed
in place. Wiring conforms to the "scrambled" spec and
anyone that's handled Roberts
radios from the same era as this pre-amp will recognise the
general design and be aware of excellent performance coupled
with incredibly poor mechanical design with little thought for
a repairman. I'm reminded of a comment by a Plessey mechanical
engineer (concerning some satellite ground station equipment)
back in the late 60s... "the string is NATO approved string
not just any old string". |
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Inside the pre-amp case
are two early printed circuit boards with the mains transformer
on the right.
All the transistors seem to
be PNP devices and are germanium rather than silicon based. The
pair in the centre, mounted on heatsinks screwed to the lower
of the two circuit boards, are Toshiba 2SB462 with the "B"
standing for PNP. The case style is TO66 dating back to the 1960s.
Maybe the marking "CDK
TP15" means something to somebody? |
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BC221M
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Another item from Dave
G3SUL is this BC221 which is a different model to my
previous BC-221-AF example seen here. The availability of
these equipments back in the 50s, 60s and 70s provided a convenient
way of meeting the terms of ones amateur radio license although
actually having one to show a GPO inspector didn't always mean
it had ever been used. |
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Dave also gave me this
wooden box. It contained a rather nice 550-0-550V transformer,
not the original Type 2 Crystal Monitor, whatever that was? |
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HP Spectrum Analyser
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Dave, G3SUL kindly donated
this equipment which comprises the HP141T, HP8552B, HP8553B,
HP8554B and HP8556B (together with a few very nice 1930s radios
which are pictured below, together with a nice clean RA17). As
you can see the spectrum analyser is in immaculate condition
unlike my usual Hewlett Packard acquisitions.
Timing is amazing because I was just about to go searching for
a low frequency spectrum analyser with which to investigate my current amplifier rebuild.
The 8556 works from 20Hz to 300KHz and includes a tracking generator
and I'm hoping this will let me measure the quality of the amplifier
in terms of linearity and distortion. Below some radios donated
by Dave, G3SUL. |
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This generation of radios from
1936 often used a fashionable shiny brass grille over the speaker.
I removed the speaker assembly and found the grille was really
badly tarnished but turning it over revealed the other side was
in fair condition. I glued the cloth in place and fitted the
grille which restores the radio's looks.
I use a brushing wax to restore
cabinets and once applied looks OK.
Below its unusual audio output
valve, an MPT4. |
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Ultra Lynx
From 1931
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McMichael
Model 364
from 1936
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A very clean example of
the RA17 with S/No. N2866. |
This has a few faults
that need clearing up.
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Skanti TRP8255
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This is the Plessey-badged
transceiver fitted in the HDRS, later NCRS, cabins that were
supposed to carry army radio traffic to attempt to bring order
back to the UK, devastated by nuclear war.
Thankfully the possibility of
this ever happening caught MoD off guard leaving the project
high and dry.
All advanced projects go wrong
because of software problems and HDRS was no different. MoD were
more to blame than Plessey because sensible timescales and costs
were always secondary to available time and cash.
The more a project is starved
of timescale and finance the worse things can get. HDRS wasn't
really required but Plessey managed to get the thing delivered
under the guise of a sort of plaything for the Army.
Later the whole thing was sold
off at bargain basement prices and here's one of the radios I
bought from a fellow radio ham...
Read more
about the Project.. which for
a period I had the dubious pleasure of managing. |
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