Some information on SCSI .. trying to fix my Grand Slam

[Sim085]

Hello,

I have a Grand Slam which was not working any more. I decided to try and fix it myself. One of the problems with it was that some of the SCSI connector pins where missing.

I decided to de-solder this SCSI connector and solder a new one. Now the Grand Slam has two SCSI connectors. To test if I did all ok I tried to do a "continuity test" from one SCSI connector to another.

I did get good results on some pins but not on others. For one of the pins there is a visible track and I believe I might have done some damage while de-soldering.

To fix this I "hacked" a wire from the pin of the SCSI connector to the corresponding pin on the other SCSI connector.

My question is this;

Can I safely to the same for all pins which fail the "continuity" test?

Here is a pic of the Grand Slam internals:

http://www.bigbookofamigahardware.co...m2000_1_sm.jpg

[prowler]

Originally Posted by Sim085

Can I safely to the same for all pins which fail the "continuity" test?

That depends on the reason for the two headers. Do you know why there are two?

I don't know the Grand Slam. It looks like a cacheing SCSI host adapter.

If there's no guidance on whether you should use one header or the other to connect a particular peripheral, then I would say you could safely connect all those pins which fail in the same way you have already connected those other two.

[Sim085]

Originally Posted by prowler

That depends on the reason for the two headers.

The manual seems to indicate that it supports two hard disks (used at the same time), i.e., one header for each hard disk.

[prowler]

Then it's almost certain that the two connectors are meant to be paralleled up.

Also, in that case, if you intend to use the adapter with two hard drives, then each must be terminated because they will be at either end of the chain.

However, if you're using only one drive, then the other header will need to be terminated, and I would expect a passive terminator to be included with the card, unless it has jumpers to enable on-board termination.

[Sim085]

Originally Posted by prowler

Then it's almost certain that the two connectors are meant to be paralleled up.

So am I understanding correctly, does that mean that every pin of one header should be connected to the corresponding pin of the other header?

[prowler]

Yes, just as if they were connected via a ribbon cable on the wiring side of the board.

Though if you see any wiring between those headers which contradicts this theory, then please proceed with caution.

Note that approximately half the pins on any hard drive data ribbon connector are conected to ground. These may may be connected en bloc.
That is why corresponding external D-Type connectors on SCSI host adapters which feature them have only 25 pins.

[Sim085]

Done! Works Great!
Thanks for your help.

[prowler]

It's good to know that you got it working. Thanks for reporting back!