Unidentified PCB in a 33ASR

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Tomas
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Unidentified PCB in a 33ASR

#1

Beitrag von Tomas »

In my Teletype 33ASR (Teleprint version) I have an unidentified PCB.

The card is marked BS292 on the sticker, on the back of the card there is a text ”TZ-197”

The Orange/White cable goes to Connector 1, cavity 6
The Grey ones goes to connector 12 on the motorcontroller BS263 and other places as well
The Purple/White one goes to connector 6 cavity14, connector 1 on the tape reader card, and some more places as well
The Blue cable goes to Connector 1, cavity 1

Can anyone Identify it, and possibly have a schematic, or identify the white the white component marked ROTA ELEKTRIK?
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ProgBernie
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Re: Unidentified PCB in a 33ASR

#2

Beitrag von ProgBernie »

The white block is a reed relais (i am pretty sure). The diode is the recovery diode to avoid voltage peaks to damage the driving circuit.
The grey cables maybe ground and the orange white drives the relais (positive voltage here)). The function of the resistor is not obvious, it seems to be connected between blue and maybe grey.

The board connections are not clear, the normal rota relais has the following diagram:
     o
 o------/ -----o
            o
The middle rows are the contact the two pins diagonal are the solenoid.

So this board is just a little relais switch board. If you want more info, attach a picture of the bottom side :)
Gruß Bernd
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Topic author
Tomas
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Re: Unidentified PCB in a 33ASR

#3

Beitrag von Tomas »

As far as I understand it

The resistor sits in series with the coil, the diode most probably a fly-back/Freewheel diode.
Now the coil is connected between number 1 and 6 in the J1 connector assembly.

One end of the relay contacts is connected to the Reader PSU (BS241 card) Edge contact number 3 and number 14 on J6 (card reader connector).
Reader PSU Edge connector 3 is a relay contact to the 0-terminal on the 18-9-0-9-18 Winding on the transformer.
The relay is operated with the Auto/Man switch on the right face-plate (not standard 33 thing I guess)

The other end of the BS292 relay is connected to one of the circuits in the Online/Local mode switch as well as number 12 and through a diode to 11 both on J4 (motorconnector)
In the scanned schematic I have, I cannot se whats connected on J4-11 and 12 on the other end, seems to be some sort of solenoid
It is allso connected to Edge connector 12 on the motor control board BS263
The Local/Online Mode switch, when i Local shorts the relay contacts.
So, whats up?

I have done about 90% of the schematic, need to verify keyboard, reader, printer and motor.


Topic author
Tomas
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Re: Unidentified PCB in a 33ASR

#4

Beitrag von Tomas »

Here is the nearly finnished schematic.
I havent checked the wiring to keyboard, printer and reader yet.
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ProgBernie
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Re: Unidentified PCB in a 33ASR

#5

Beitrag von ProgBernie »

Hi Tomas, he diode has the cathode connected to the upper orange/white wire on the positive line PIN 11 and the cathode down to the blue line PIN 17. Otherwise the diode would shorten the coil when the polarity is as indicated on the board.
Gruß Bernd
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FredSonnenrein
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Re: Unidentified PCB in a 33ASR

#6

Beitrag von FredSonnenrein »

But the other end of the cable connection to the "BS292" is not connected at all, so the actual polarity of the coil control voltage is not known.
Grüße,
Fred Sonnenrein, Braunschweig
i-Telex 952741 (Lo133), 531075 (Creed75), 8579924 (T100s), 792911 (T68d) oder 781272 (T100)
Bei Besetzt bitte 531002 versuchen.


Topic author
Tomas
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Re: Unidentified PCB in a 33ASR

#7

Beitrag von Tomas »

There is most likely a few errors in the schematic, at least it is a start, I am going to vive in to it and correct the faults.
Finding out what is Anode and Cathode on those Diodes isn't that easy, have to measure them and see what it tells, however the coil will probably fuck up the measurements.

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ProgBernie
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Re: Unidentified PCB in a 33ASR

#8

Beitrag von ProgBernie »

The unpopulated other side of the board shows the direction of the diode and the plus sign indicates the polarity (unless they have a plus und a double plus voltage). You can see the copper traces through the board, both sides seem identical :)
Gruß Bernd
--
Fernschreibstelle Labenz
898906 laeng d


Topic author
Tomas
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Beiträge: 9
Registriert: Mo 28. Okt 2019, 17:44
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Re: Unidentified PCB in a 33ASR

#9

Beitrag von Tomas »

Oh, I am so embarressed, I did'nt see that, need new spectacles I guess.

One other question, since it is different from the Teleprint 390 schematic I found here, TX and RX-lines can anyone identify them?

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