Here's a Photo of a normal PDS adapter and the PVT adapter pay attention to the 343S1027's and the backs of the boards
Fascinating. Between the two boards, it seems all the serial capacitors mentioned in DCDMF3 are gone - only the resistors are left. The markings on the resistor packs on the back (big yellow package) aren't readable in the picture, are they readable on the real thing?
On the front side, they have different packs of resistors on the NuBus line (the three yellow or black packages on the top right). The three yellow packs are
SOMC1605 271/471G packs from Vishay, so 270 Ohms to one line and 470 to the other (one is likely +5V the other ground, not sure which is which from the pictures). The other adapter in the same picture only has '8940' and '143J ' markings, the first is a production date and the second I couldn't trace. I've seen pictures with CTS packages (greenish grey) labelled 767165171A, those are
767-series of the same value as the Vishay parts (270/470). But the Radius adapter that
@Trash80toHP_Mini posted in
Project30 - fourth edition has '9145' and '8j08' markings from BI - they are likely to be
TT Model 628 packs, similar packs but with a lower resistance of 220/330 ohms.
The 343S1027 from their size and some tracks and the IIci/IIcx schematics are likely just drivers, consolidated replacements for the set of 8x 74ALS651 in e.g. the IIcx. They need 8 as they have 4 (4x8bits per chip == 32 bits) for data and 4 for addresses to connect the split address/data bus of the '030 on the multiplexed AD line of NuBus. Each 343S1027 replaces 4x 74ALS651, 2 on each side, so they can multiplex 16 lines with less board space. 74ALS651 aren't made anymore and I have never found a "standard" equivalent to 343S1027 (from Harris or anyone else), but I suspect 74ABT651 would do the job just as well.