RS422 weird glitch

[Deft]

Hello!

So here is the problem:
Emulator II + HD, model 6065 serial 2539. HDD removed and HXC installed as 1st fdd, and fdd as second.
Problem is that sometimes, while trying to send or receive bank or sample from/to EII (it doest matter if its EMXP and emuser, or MAC with Sound Designer, so problem is definately in EII not cables etc), EII hangs with "under control of macintosh" on display and not reacting on any button. Power off and reboot helps.
Problem is not happening systmatically - I can work normally for 3 hours without any problems sending and receiving banks and samples. but it also can happen 10 times during 10 minutes.

I`ve replaced both IC`s for RS422 - its IC108 and IC132. Checked motherboard for microcracks - all seems to be ok.

Any ideas? )


Regards,
Kirill

[Wolfram]

Do you have a scope, can you measure the clock signal from you RS422 ?

[Deft]

I`m not that good in electronics, but I have a friend who can do that, what needs to be checked?

[reginator]

Check the "Computer Interface" connector on the back of your EII for loose sockets. Over time with repeated use, connection pins inside most connectors will lose their grip. They make special tools for checking pin-grip (known as Contact Retention Testers) but you can use a spare pin that has been crimped on a wire to test this. Loose connections can give lots of errors in computer operated things.

If you open up the EII then check that none of the solder where the Computer Interface connector mates with the PCB is disturbed / cracked / loose. You'll have to take out the PCB to do this. I tell you this because I just recently repaired a Tascam recorder and Casio CZ-101 that had loose solder joints. The operation returned to normal after re-soldering.

Also check your interface cables to make sure they're not frayed or have intermittent operation due to broken wires.

[Deft]

Thanks, checked that already - that was my guess also, but everything seems to be ok. And cable interfaces - as i said same problem with Emuser on PC and Mac with sound designer, cables are different )