I am working on some hand-sketches for schematics.
First I am to go for the primary side of the transformer, the secondary electronics probably have to wait a bit- it seems that the hex/allen Screws that hold the heatsink are US standard, not metric like my tools...
Anyway, I could need some help with the transformer- it seems that is double-tapped and has multiple voltage levels on its secondary outputs.
Rough going of wiring as follows:
Cable to wall outlet->single Fuse on line, after that to the switch in the front that switches line and neutral, this goes to a connector board. Nicely done, as it allows for some bridging of connectors. From this board on it goes to the transformer.
This routing board has 12 terminals. I numbered them 1,3,5,7,9,11 for the side coming from the main switch, 2,4,6,8,10,12 for the side facing the transformer.
1: Black wire from Switch/Line potential
3: not connected
5: Bridged to 1
7: bridged to 9
9: bridged to 7
11: light brown wire from Switch/ neutral potential
2: not connected
4: brown wire to transformer
6 grey wire to transformer
8: white wire to transformer
10: black wire to transformer
12: other black wire to transformer
Removed the secondary wiring from the pcb and powered the system up. Voltages measured are like the following:
1/5 (L)-> PE 235 V
3 ->PE 229 V
7/9 ->PE 117V
11 (N) -> PE 0 V
On the secondary side it looks like:
3 connectors coming out. Two of them providing 8.7 VAC as supply voltage to the LCD displays. Each of them is isolated against each other.
The third connector goes to the PCB board, is manufactured from Panduit and looks like an IDC connector type on the cabling side. 6 Pins, one of them PE.
Pins and voltages against PE:
1-orange 4V
2-orange 5,4V
3-black 9,5V
4-yellow 3,9V
5-yellow 15,1V
6- PE green 0V
For curiosity, I checked some voltages against line potential:
1-orange 17V
2-orange 15V
3-black 30V
4-yellow 35V
5-yellow 24V
6- PE green 235V
Conclusions I drew from this:
a) the primary side of the transformer is probably double-tapped to allow adjustment for a supply voltage of whether 110V or 220V (given its date of manufacture somewhere in 1987 according to the date code of the parts)
b) output is not floating (therefore some caution is needed, as a isolation transformer and differential probe for my oscilloscope are still on my shopping list)
c) the transformer is having multiple windings, especially for the secondary side
Question: As this is my first approach to this kind of transformer- could someone point me in the direction for some literature and how to draw it in a nice way in schematics?
Voltages here: