Author Topic: Siemens exchange do not work  (Read 1804 times)

Offline dsk

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Siemens exchange do not work
« on: May 14, 2021, 03:20:00 PM »
Anybody who has schematics for this one, cant get it working. :(

Offline RB

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Re: Siemens exchange do not work
« Reply #1 on: May 14, 2021, 07:16:26 PM »
Sir... You dive off the deep end don't you???
Is that a transformer?
I bet if you follow pins 1 &2, and 4 & 5 to that white term strip, you can find the Vcc in???

Offline dsk

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Re: Siemens exchange do not work
« Reply #2 on: May 15, 2021, 12:27:56 AM »
Yes it is a small compact transformer, mot sure but I believe it is for the transfer of sound signals.

Offline RB

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Re: Siemens exchange do not work
« Reply #3 on: May 15, 2021, 04:29:03 AM »
Ok, an iso transformer.
Odd that it has 2 primary windings???
Next attempt...
First pic, lower right corner, blue rectifier...
Where do the 2 yellow wires go?
Guessing that big transformer next to it?

Offline dsk

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Re: Siemens exchange do not work
« Reply #4 on: May 15, 2021, 11:25:03 AM »
The 2 yellow is the AC wires, and the rectifier did not work well, so I changed it.  (It had a little smoke leakage, and I was not able to put that smoke back  ;D )

When I go off hook some relay are activated, and one is pulsing when I dial, but nothing more is happening.

When I press one relay, one of the phones is ringing at 60V mains frequency (terrible sound)

Offline rdelius

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Re: Siemens exchange do not work
« Reply #5 on: May 15, 2021, 01:14:50 PM »
That transformer has a split primary winding most likely to select 120 or 220 v taps

Offline dsk

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Re: Siemens exchange do not work
« Reply #6 on: May 15, 2021, 01:46:13 PM »
Power transformer: 

Offline RB

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Re: Siemens exchange do not work
« Reply #7 on: May 15, 2021, 03:14:10 PM »
So, guessin you have the power part solved.
And an incoming pots line? with a couple extensions connected.
My guess would be something with the line relay contacts???
or where they go next?
unfortunately, we are at the end of my knowledge of that kind of system.
So I cannot offer much more help.
hopefully someone with background will chime in and bail me out.
Hope you get is going soon.