I would like to respond to an old archived thread in case anyone in the future needs this information.
I was in desperate need for this and was fortunate enough to find the information, I feel I should share it for those not so lucky.
https://www.electronicspoint.com/threads/power-requirements-for-proto-board-pb-503.61310/
Looking at the female connector on the PB-503 board, there is a 5 pin din input. If we label the inputs on the board from 1 to 5 from left to right, the input voltages needed are:
1: -26 volts*
2: Not connected
3: Ground
4: +10.5 volts
5: +26 volts*
*The measured output of the transformer is closer to ±22.5v. The 10.5v output reads accurate.
PB-503 Input connections:
The current outputs for the 400 CA1 transformer are listed as +10v 1.2A, ±26v 0.6A
I was in desperate need for this and was fortunate enough to find the information, I feel I should share it for those not so lucky.
https://www.electronicspoint.com/threads/power-requirements-for-proto-board-pb-503.61310/
Hello,
I have a PB-503 that has been lying around for a while and somehow got
separated from its power supply. It's the older style with a 5-pin DIN
connector on the back left corner (as opposed to the newer ones that
have the power supply entirely inside the cabinet.) Very nice, with
all sorts of signal generators and power supplies, but next to useless
without the right input voltages.
Does anyone have one of these handy and can provide the
pinout/voltages of the "wall-wart" adapter that plugs into the DIN?
All the unit says is the adapter number is "400 CA1."
I would appreciate any help!!
--------------------------------------------------------------------------------------
Doug the Desert Tripper - Exploring Southern Cal deserts and the Net since '94
www.geocities.com/destrip
destrip at sonic dot net
--------------------------------------------------------------------------------------
Looking at the female connector on the PB-503 board, there is a 5 pin din input. If we label the inputs on the board from 1 to 5 from left to right, the input voltages needed are:
1: -26 volts*
2: Not connected
3: Ground
4: +10.5 volts
5: +26 volts*
*The measured output of the transformer is closer to ±22.5v. The 10.5v output reads accurate.
PB-503 Input connections:

The current outputs for the 400 CA1 transformer are listed as +10v 1.2A, ±26v 0.6A