Re: Zenith Z-90 startup
Hello, I am reading through message archives and came across your post. Did you get your h90 sorted out? Craig
Re: Zenith Z-90 startup
On 05/12/2018 02:29 PM, Mister PDP wrote: Hello, I have had this issue with a number of H/Z89s I have. The terminal board and the logic board are two separate systems, so it seems to be common for the logic board to go down while the terminal board keeps working. I would check voltages on the logic board, then take it out of look for blown tantalum caps and burnt traces. The tantalum caps used in these systems seems to like to cause issues, with 5\8 of my systems experiencing issues with them. If that doesn't do the trick then check the power regulators on the logic board, as those can cause issues too. Thanks, I'll take a look. I've actually got lots of technical docs for the system... schematics, firmware source listings, CP/M BIOS source listings etc. - Zenith seemed to be really good in that regard. If it's not somehow expected behavior then I'll do some digging regarding caps, voltages etc. and go from there. Will reseat chips, too - when I pulled* the boards yesterday to do some general checks I did notice quite a bit of tarnishing on IC legs, which makes me wonder if some of them haven't rotted from the inside-out (as they sometimes do). * What an odd setup! Nice hinged case for access to the inside, but then lots of unscrewing and unplugging stuff and digging around right next to the CRT in order to actually *do* anything. I half wonder if Zenith's intention wasn't to make all the boards hinge out backwards too, and then they found that they just couldn't quite make it work. cheers Jules
Re: Zenith Z-90 startup
Hello, I have had this issue with a number of H/Z89s I have. The terminal board and the logic board are two separate systems, so it seems to be common for the logic board to go down while the terminal board keeps working. I would check voltages on the logic board, then take it out of look for blown tantalum caps and burnt traces. The tantalum caps used in these systems seems to like to cause issues, with 5\8 of my systems experiencing issues with them. If that doesn't do the trick then check the power regulators on the logic board, as those can cause issues too. I'm not too familiar with the terminal setting on these systems, but I would check the DIP switch settings with the manual and see if there are any settings changed. There are many good sources for the manuals online last time I checked On Sat, May 12, 2018 at 1:23 PM, Jules Richardson via cctalk < cctalk@classiccmp.org> wrote: > > Any Zenith Z-90 owners out there (which appears to be the same thing as a > Z-89 / Heath H89, but with a DD soft-sectored disk controller)? > > I was given one up a couple of days ago which isn't giving the expected > "H:" prompt at power-on - but it *does* give a blinking cursor, and hitting > off-line lets me type, and characters get echoed to the screen. > Right-shift-reset clears the screen and gets me back to the cursor. > > Before I dig deeper, I'd like to verify that this isn't a feature, i.e. > that it's not auto-magically dropping into "terminal mode" at startup :-) > Unfortunately while I have masses of documentation for the machine, I'm > lacking a basic user guide which might shed light on any such mode; some of > the more detailed documentation that I have talks about rerouting the port > cabling to use the system purely as a terminal, but doesn't mention doing > any other configuration. > > cheers > > Jules >
Zenith Z-90 startup
Any Zenith Z-90 owners out there (which appears to be the same thing as a Z-89 / Heath H89, but with a DD soft-sectored disk controller)? I was given one up a couple of days ago which isn't giving the expected "H:" prompt at power-on - but it *does* give a blinking cursor, and hitting off-line lets me type, and characters get echoed to the screen. Right-shift-reset clears the screen and gets me back to the cursor. Before I dig deeper, I'd like to verify that this isn't a feature, i.e. that it's not auto-magically dropping into "terminal mode" at startup :-) Unfortunately while I have masses of documentation for the machine, I'm lacking a basic user guide which might shed light on any such mode; some of the more detailed documentation that I have talks about rerouting the port cabling to use the system purely as a terminal, but doesn't mention doing any other configuration. cheers Jules
