The "wirewrap" pins on the 11/23 and many
other DEC boards are short pins
that are accessed on the /component/ side of the board and used for jumper
links, eg to select baud rates, or in the case of an 11/23 to set the boot
configuration and other things. See for example the images at
http://store.reuseum.com/DEC_M8186_F11_Fonz_CPU_Processor_Board_
Q_Bus_p/000021514002g14store.htm
There's a group of pins with their jumpers to the right of the middle
40-pin
IC.
On that pic those links look like a DIL socket, not wire wrap pins. But if
wire wrap pins are used like that its not surprising they work loose.
I would expect them to be plated steel and therefore have characteristics
that are bad for soldering. That is:-
1. Have a relatively large mass as they need to be stiff to wire wrap
2. Therefore have a large thermal mass or heat capacity
3. So they are slow to heat up -> may not get hot enough to solder
4. Slow to cool -> likely hood of dry joints if they move while cooling
5. Poor solder whetting as they can be hard to clean....
So not surprising they sometimes work loose.
Look carefully and you'll see 5 (IIRC) other
pairs, including one near the
top
left of the crystal oscillator with a jumper on it,
and one with no jumper
to
the right of the smaller IC two rows above the main
jumper group. Other
DEC boards such as DLV11J and the notorious (because of gazillions of
jumper
options) MXV11B do actually use wirewrap to such pins
rather than jumpers,
in a few cases 2-level wrap.
--
Pete