IC86 still in place on a 1770 installation…

[Bitstik]

Trying to get my eBay-find BBC working.
It’s turning on and I’ve now got the keyboard working.
When I try to format a 3.5” dd disc it goes through the motions but then I get a disk error, presumably on verify.

The machine came with a viglen 1770 interface which I understand is a facsimile of the Watford one.

It came with its own viglen DDFS which wouldn’t format the disk so I loaded a Watford rom instead.
This doesn’t work either.

Thinking the 1770 was possibly damaged I ordered a new 1770 (1772 in fact) upgrade board but note that I have to remove ic86 and replace with a jumper instead. On the current installation IC86 is in place.

I wonder if this is the reason my drive isn’t working? Is it possible somebody performed a 1770 installation and left
IC86 in place by mistake?
There is also this odd thing on the board which I thought was a resistor but, on removing the cover, it’s a “connector” of some sort which is unconnected at one end but through-hole connected to one of the long pins on the underside of the PCB

Any help gratefully received.
Thank you

[arg]

That socket connector looks to be picking up NWDS from pin 10 on the 8271 connector - quite likely it was used to run something like a sideways RAM expansion, not directly connected with the floppy interface (ie. just a convenient place to pick up that signal).

The necessity (or otherwise) to remove IC86 will depend on the specific design of the expansion board - I'm not familiar with these particular ones, but it's quite likely one needs it and the other doesn't. The one in your photo has an 8MHz crystal on board, so maybe doesn't need to pick up 8MHz (which is what you'd get by linking out IC86).

[Bitstik]

Many thanks for such a detailed response.
Onto other investigations…
I’m going to replace the psu- it needs recapping anyway - so I’m hoping a new psu might improve things in case the old
Psu was giving out flaky 5v etc.

[Bitstik]

Found the answer in another thread - tarnished connector pins on bbc- now cleaned and formatting /verifying fine!
Result!