Intial examination:
The logic on the board is fully combinational, no pesky clocks or other noise inducing signals.
The value of the 16bit BCD inputs are latched via IC2 and IC3 (74HC573A Octal TransparentD-TypeLatchesWith 3-State Outputs) and displayed on the front 4 digit 7-segment display, via the decoder ICs 7-9 (HEF4511BT BCD to 7-segment latch decoder drivers).
Also the input values are entered in a BCD to binary converter EPROM IC14 (M27C1024 64KBx16 UV EPROM), the outputs go into IC15 (AD7535JN 14bit DAC with parallel inputs ) that uses as reference IC16 (AD587KJ or JN 10volts precision reference).
On the board are a large number of precision OP, either OP07 or OP177, some relays and a mystery EPROM, IC1 (M27C128 16KBx8).
On the front panel there are two 2 positions, non-retaining switch ( Ein - 0 - Ext ein) and (Aus - 0 - Setz), most likely switching the reference with some external one.
Recommended BCD switches:
https://www.ebay.de/itm/Kodierschalter-0-9-BCD-Codierschalter-Vorwahlschalter-Pushweelswitch-1-Stuck/312231336643So much for now, lots of things TODO.
Power (before pinout):
+5V - Over C2 (Tested OK)
-15V - Over C4 (Not-tested!!!, polarity OK, actual value TBD).
+15V - Over C6 (Not-tested !!!, polarity OK, actual value TBD).
Fun (?!?) fact: in my board the line on the capacitor body signifies (-) but fortunately the correct polarity is printed on the PCB silk mask.
The same BCD switches from Aliexpress, just ordered!
Still awaiting the boards ....
Hi,
I have two of the boards and I've dumped the EPROMs. The BCDBIN (27C1024) has identical contents on both boards (as expected) and contain a lookup table. The mystery EPROM (27C128) is different on both boards. They are essentially blank (filled with &00 not &FF) except for a few bytes which are possibly some sort of addressing for the card? Binary files below.
McBryce.
Interesting! Only 2 Bits difference. Let's see what the other board owners report.
btw: what are you using for the EPROM read-out? I do not have anything for this but it's never to late.
Thanks everybody for your contribution, now the bit two tasks are waiting
- Connector pinout !!!
- Analog part schematic, what are all the OP doing ?
If something's left in WE, I'll try the pinout, at least to start it.
Cheers,
DC1MC
It's 40 years ago when I built my last EPROM programmer for a Z80 based OEM system (U880 in East Germany) and wrote the assembler code.
I think the 2nd one is enough for my needs. Thanks for the link! I ordered one but it takes time on the slow boat from china
First idea was that the code line is a serial number of the board but than I saw that the datas are at different addresses in both EPROMs.
Hope my boards arrive today but DHL is like the weather, the forecast is never correct.
Thanks everybody for your contribution, now the bit two tasks are waiting
- Connector pinout !!!
- Analog part schematic, what are all the OP doing ?
If something's left in WE, I'll try the pinout, at least to start it.
Cheers,
DC1MC
I have already started on some of the pinout, but I still need to find out how the connector pins are normally numbered. There's no pin numbers on the physical connectors I have.
McBryce.
I found the shorter version just for that connector. I'll use the numbering they supply here (1 to 32 with rows ABC).
McBryce.
DHL is better than expected. My boards arrived.
Attached first shots for your entertainment.
Seems to be a multilayer PCB with ground and power supply in the middle?
DHL is better than expected. My boards arrived.
Attached first shots for your entertainment.
Seems to be a multilayer PCB with ground and power supply in the middle?
Welcome to the (very exclusive) club
!!!
Let's make the roll call, who has the boards and read the topic still ?
Cheers,
DC1MC
DHL is better than expected. My boards arrived.
Attached first shots for your entertainment.
Seems to be a multilayer PCB with ground and power supply in the middle?
Welcome to the (very exclusive) club !!!
Let's make the roll call, who has the boards and read the topic still ?
Cheers,
DC1MC
Me, but I didn't have enough time to look at the boards any further yet.
McBryce.
Sorry it takes some time to start. Real life implications during f@%&ing shutdown with 3 kids at home
and full time job give me only short interrupts for my bench.
(nach dreizehn Monaten zweifelt man immer mehr an der Fähigkeit unserer geilen Regierung)
Has someone ask the seller where the boards come from?
Unfortunately, he doesn't ship to UK
Waiting for my boards & connectors.
Unfortunately, he doesn't ship to UK
Fortunately, in my case - since I have some standards and don't
need another
For those who are as
anal OCD as I am, I made this sheet to help on pinout reverse engineering. The connector picture is of the mating connector, not the connector on the populated PCB.
McBryce.
It seems that all boards are sold. That‘s good because I couldn't suppress my wish to buy more boards.
Not going to have much more time today, so here is my Pinout info for today.
McBryce.
Not going to have much more time today, so here is my Pinout info for today.
McBryce.
Lets add something extra, maybe next time we can have some common editable format, let's kill all the low hanging fruits:
A B C
01 xxxxxxx xxxxxxx xxxxxxx
02 xxxxxxx xxxxxxx xxxxxxx
03 xxxxxxx xxxxxxx xxxxxxx
04 xxxxxxx xxxxxxx xxxxxxx
05 xxxxxxx xxxxxxx xxxxxxx
06 xxxxxxx xxxxxxx xxxxxxx
07 xxxxxxx xxxxxxx xxxxxxx
08 xxxxxxx xxxxxxx xxxxxxx
09 xxxxxxx xxxxxxx xxxxxxx
10 xxxxxxx xxxxxxx xxxxxxx
11 -15V -15V -15V
12 -15VX -15Vx -15Vx (IC20 - OP07)
13 +15V +15V +15V
14 +15VX +15Vx +15Vx (IC20 - OP07)
15 GND GND GND
16 GND GND GND
17 +5V +5V +5V
18 +5V +5V +5V
19 xxxxxxx xxxxxxx xxxxxxx
20 xxxxxxx xxxxxxx xxxxxxx
21 xxxxxxx xxxxxxx xxxxxxx
22 xxxxxxx xxxxxxx xxxxxxx
23 xxxxxxx xxxxxxx xxxxxxx
24 xxxxxxx xxxxxxx xxxxxxx
25 xxxxxxx xxxxxxx xxxxxxx
26 xxxxxxx xxxxxxx xxxxxxx
27 xxxxxxx xxxxxxx xxxxxxx
28 xxxxxxx xxxxxxx xxxxxxx
29 xxxxxxx xxxxxxx xxxxxxx
20 xxxxxxx xxxxxxx xxxxxxx
31 xxxxxxx xxxxxxx xxxxxxx
32 xxxxxxx xxxxxxx xxxxxxx
It seems that all boards are sold. That‘s good because I couldn't suppress my wish to buy more boards.
There are just a few connectors left, if you need them now is the time to get them.