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Old July 6th 07, 04:24 AM posted to alt.binaries.pictures.radio
James Pernal James Pernal is offline
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First recorded activity by RadioBanter: Jul 2007
Posts: 2
Default Lorenz Portable AM-FM - attached files (1/1)

In article wl8ji.15024$Io4.12763@edtnps89,
"Neil S" wrote:

Jim, if you find out anything, or you delve into the circuit on this set, I
would really like to know how they did the detector for FM. Since isolated
cathode diodes are almost unknown in battery heated versions, did they use
crystal rectifiers?

Neil S.

"James Pernal" wrote in message
...
I'm trying to ID this Lorenz battery and AC AM-FM portable. Tube lineup
as found DC 90, DF96, IR5 DK91, DF96, DF97, DAF96, and 3V4 DL94.

As you can see no labels. US version is the only label. Not in
Beitmans,Nostalgiair. Radiomuseum (non-member) and other European
sources imply its tube lineup is close to a 56, but this does not have
LW or SW. The 55 does not have the DC90 converter horizontal underneath
the variable cap.

Any ideas? Unique model for US?

Thanks Jim



Well if some good soul can ID the set, and maybe even supply a
schematic, all would be known!

I did look under the chassis and there are two OA72 black diodes. These
cross to 1N34/1N60, so I assume they are the ratio detector. This set
may be as old as late 1954, so its interesting the diodes are there.

The DC90 is a VHF battery tube, which has no cross to a US tube from
what I've read. The DAF96 which crosses to a 1AH5 has a single diode
plate, which I assume is used as the AM detector.

I suppose I can trace out the entire schematic, but getting one would
help and save tons of time. I'm not sure on the A battery voltage,
guessing 9 Volts from some other Lorenz sets around this time. Do they
switch filaments between the converters to make up 9 V? Are all in
series and a dropping resistor means a 12 V A battery? I'd like to
determine the full drop such that I can ease up on replacing the
selenium rectifier, with a diode and resistor, such the the proper
voltages are set.

Most of the broken dial cord is intact, but again service info would
speed things up.

Read about Europe being the only place that made battery FM portable
radios, and when I found this one, I wanted it and snapped it up

Jim