Blizzard 1260 - SCSI-IV trouble

[Hyperspeed]

I have a Phase5 Blizzard 1260 accelerator board and a DCE SCSI-IV
adaptor (v8.5 ROM) but I tend to get a lot of "There is a Checksum
Error on xxx".

When I click retry the error vanishes!

I have changed memory from EDO to FPM, have active termination on the
last device, cable length appropriate for Asynch mode and I have used
only Phase5 utilites for HD prepping (no mixing prepping tools).

I can't work out why I get these sporadic errors, am I picking up RF
interference? My cable length is 2.5m including internal and the
scanner. The limit for Asynch SCSI-1 is 4m...

When I squeaze the SCSI-IV to 25-pin plug the error sometimes doesn't
re-occur as though I'm absorbing RF or making a better contact ont he
pins.

I've changed cable though and the problem is still there! I've heard
about increasing the Error Retries but surely this is a sign of a bad
chain in the first place!

Help me SCSI-IV users!

[Hyperspeed]

I'm not sure what a zebra strip looks like. What's on the DCE SCSI-IV
kit is like a little female block with curly pins inside, like smooth,
springy things that squeaze onto the PCB of the Blizzard 1260
mainboard.

The 1260's gold contacts became very yellowy like matt-yellow and not
shiny gold so on the SCSI-IV expansion connector I use a blunt tweezer
to scrap off the oxidisation to make it shine again (making sure not
to scratch but to gently ebrase (whilst keepign earthed).

This seemed to work for a while ontop of the FPM (which replaced the
EDO SIMM), but things have gotten worse recently.

I have a converted PC PSU so plenty of juice and I've tried varying
cable length and drive combinations to no avail.

The trouble is my Mask/MaxTransfer setting is set to Zorro3 hex speeds
that can go up to 16mb/s...  this concerns me and I'd like to try the
settings for the same speed as an IDE drive just for curiosity.

Any ideas?

[Hyperspeed]

Castellen, what about the trapdoor expansion connector... does that
oxidise over time too?

I thought gold was chosen for connector because gold does NOT oxidise.
Has Phase5 been sold some brass and fobbed off as gold?

:-)

Does Isopropyl Alochol dissolve tarnish or just finger grease?
Wouldn't I need something like Brasso medal polish or something to
shine up the contacts?

I do get more reliable performance when I remove and re-install my
B1260 + SCSI-IV but I'm more suspicious of the dodgy 50-pin to IDC
adaptor that I made myself. It makes circuits but I'm not sure about
insulation or shielding.

I heard that you must remove a terminator if your chain combines
internal and external cables...

Any ideas are greatly appreciated!