Telefunken RT200 User Information page 8

Contents
Some Reverse Engineering
Since the tuner's PCB is single-sided, it is principally possible to reverse-engineer the device by following
the traces, but at least in Germany, there is a much simpler way: go to www.schaltungsdienst.de, the web
page of the Lange circuit service in Berlin. This company offers a unique service: it archives schematics
and manuals for about any piece of audio/video equipment that was ever sold in Germany. Manufacturers
usually only have schematics for the newer devices, but Lange always gets a copy of the schematic and
stores it (hopefully) forever. It might even happen that when you ask a manuacturer for an older schematic,
they will automatically forward your request to Lange. Of course this service is not free; expect about
20..40 DEM plus shipping, depending on the number of pages to copy. I however think that this is well
worth the money, given the amount of time and nerves you save. Fortunately, this schematic already gives
the pin functions of the central microprocessor IC (a Matsushita MN4500 by the way, but that doesn't help
anyone...):
Pin
Name
No.
1 Vss
2 LW
3 MW
4 FM
5 OUTLED OUT
6 MUT OUT
7 LATCH OUT
8 DIGIT OUT 5
9 DIGIT OUT 4
10 DIGIT OUT 3
11 DIGIT OUT 2
12 DIGIT OUT 1
13 DIGIT OUT 0
14 KEY IN 0
15 KEY IN 1
16 KEY IN 2
17 KEY IN 3
18 STAT DET
19 PWR DET
20 KEY IN 4
21 KEY IN 5
22 BCDOUT 0
23 BCDOUT 1
24 BCDOUT 2
25 BCDOUT 3
26 TEST
27 RESET
28 GND
29 LOCKDET IN
Direction
---- Ground
Output goes high if switched to long wave AM (unused on the RT200)
Output goes high if switched to medium wave AM
Output goes high if switched to FM
Output goes high to turn tuner on
Output goes high to mute the AF output
Output controls data transfer to the synthesizer chip
Output row selectors for the display/keyboard matrix
Output
Output
Output
Output
Output
Input sense lines for the keyboard matrix
Input
Input
Input
goes high when a signal of sufficient quality is received; needed for
Input
auto scan
Input issues a 'reset pulse' after the main supply comes back
Input sense lines for the keyboard matrix
Input
Output contols the decoder driving the station key LEDs
Output
Output
Output
Input unused input
Input low-active reset for the CPU
---- Ground
goes high when the synthesizer's PLL has synchronized to the
Input
programmed frequency
Function
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