scsi sca to non-sca

[chelseayr]

I've noticed a few older topics on this but just wanted to recheck, is a 80-to-50pin adapter with just one resistor and a row of user jumpers adept enough for to use a newer scsi hd with 50pin ribbons?
(I do know about it being mentioned that the hdds themselves also has to support the protocols too, just wondering about the physical aspect alone at this point nevertheless)

this is just an example link of what sort of adapter I was talking about

SCSI SCA 80-Pin To IDC 50-Pin Male Adapter SCSI 80-50 Card | eBay

Find many great new & used options and get the best deals for SCSI SCA 80-Pin To IDC 50-Pin Male Adapter SCSI 80-50 Card at the best online prices at eBay! Free shipping for many products!

www.ebay.ca

 

[max1zzz]

They are hit and miss, that type of adapter has no termination so that will need to be provided by another device in the chain or by a passthrough / external terminator, the issue with this though is that it still leaves half the bus on the drive unterminated when connected to a 8bit 50 pin bus, some drives are OK with this while in 8bit mode however some are not.

In regards to compatibility with newer drives, those adapters will most likely not work with U320 drives as most of those will require full buss termination to have any chance of working on a 8 bit bus, compatibility with U160 drives will be much better but again some will not work unless the full 16 bit bus is terminated

(Not wanting to sound like I am pushing my own products too much here...) I do sell SCA - > 50 pin adapters with full termination here: https://68kmla.org/bb/index.php?threads/fs-terminated-sca-80-to-50-pin-scsi-adapters.38094/ these have much better compatibility than the cheap adapters (Although they won't help with some newer drives that just don't support working on a 8 bit bus)

As one last note, if you don't already have a SCA drive I would always go for the 2.5" seagate savvio drives as they have very good compatibility (Despite being a pretty recent U320 drive!) the work fine with the cheap adapters provided some for of pass through / external termination is provided (they also work great with my adapters )

 

[chelseayr]

thanks max1zzz I see what you meant, now I know!

if when I do get my system and the hdd upgrade I'll consider your adapter

funny enough I had looked up one of the savvio series before due to comparing a 'new' 2.5" (in this case the ST936701LC) to an 'old' 50pin 3.5" drive as far as seagate pdfs went. not surprisingly the thermal power was very alike which told me I likely won't have to worry about intentionally overheating one drive in a generous case