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View Full Version : Northstar Advantage 8/16 no video



leaknoil
April 12th, 2009, 05:57 PM
I picked up a Advantage 8/16 this weekend from someone that used to work for Northstar. He told me it hadn't been turned on in 20 years and well it looked like it. Its still in excellent condition but, needed some serious cleaning.

Anyway, made it all new looking and reseated everything that could be reseated. All looks good. Power it up and get one beep and nothing more. Fuse in the power socket blew. Luckily it had a spare in it. Swap them and now it beeps and lights up and will even load a disk when I randomly mash keys but, the screen shows nothing. Nothing changes when I adjust the brightness knob in the back. It doesn't seem like the tube is being powered or may be dead. No typical CRT sounds and doesn't feel warm or make the hair on my arms stand up when pressed against it.

Dead tube ? I know nothing about the CRT side of old computers. Honestly I dont like messing with them. Welcome to any suggestions. Double checked all connections and they appear fine.

He also gave me what look to be original factory blue print schematics for the thing. Has hand written corrections on it and is an actual blueprint not something out of a manual. I guess he designed the production floor for the Advantage there. Also the internal telephone directory for Northstar in 1984 which is kind of cool. That and 50lbs of other docs. I'd love to get this working.

Chuck(G)
April 12th, 2009, 07:10 PM
If you take a peek at the neck of the CRT when the unit's powered on, can you see the glow of the filament? If not, the jug may be toast. Or about a dozen other things...

leaknoil
April 12th, 2009, 08:36 PM
If you take a peek at the neck of the CRT when the unit's powered on, can you see the glow of the filament? If not, the jug may be toast. Or about a dozen other things...

Might be hard. They put the damn connection to the motherboard in about the perfect place to make it really hard to open and have it connected.

leaknoil
April 12th, 2009, 09:22 PM
Well I did the only thing I could remember from my days of analog tv and wacked it on the side. Couple times and it did what it did back then and brought it back to life. The wack on the side is really the best tool in my toolbox.

I guess the next thing is figuring out how to make some disks for it. I have what looks to be gdos 2.0 and GCP/M 2.2/1.2.0 disks. Oh and BDS "C" compiler disk 1 of 2 which I am sure is very useful. Also a version of MSDOS 1.25 that runs on it for what good that does me with hard sectored floppy drives.

It has a serial card. Is there something like ADTPro for the Northstar and where can you get hard sectored disks anymore ?

Chuck(G)
April 12th, 2009, 09:29 PM
It has a serial card. Is there something like ADTPro for the Northstar and where can you get hard sectored disks anymore ?

You really hate to advise anyone to give the thing a whack, but connectors do get corroded and loose. Good for you for having figured it out.

You could drop the folks at Athana (http://www.athana.com) for a quotation on some HS 5.25" disks. Just hold onto your wallet...

I've heard of people making a jig to punch the sector holes in SS diskettes.

Dr_Acula
April 12th, 2009, 09:55 PM
ha ha, yes whack it on the side. I learned to do that when I was 3 and the old valve TV picture used to start rolling.

Only disk 1 of 2 for the C compiler? Well, all those files and more exist on the altair simh site as well as on the walnut creek CD archive. You just need some way of porting them across. A pile of blank disks would be the first priority. And then the most basic software to talk to the serial port. Is there xmodem or kermit or ymodem on any of the disks?

chuckcmagee
April 12th, 2009, 11:40 PM
I used the same "fix it" technique on my Osborne OCC2. Unforunately, it fixes the video for anywhere from 325 milliseconds to 30 seconds. I have to get up the mental energy to take the sucker all apart AGAIN, and resolder the horiz high power transistor legs AGAIN. As previously stated, my repair worked great until I put the sucker back together.

chuckcmagee
April 12th, 2009, 11:42 PM
Oh, if you get pissed off or tired with the 8/16, be sure to let me know!! My normal Advantage will boot 1 time out of 30. In 1 or 2 weeks, I should have a replacement motherboard for the Advantage.

tezza
April 13th, 2009, 01:02 AM
Sounds like you do have some dry or faulty solder joints on a connector or a component so at some stage you might want to take a good hard look at the circuit boards around the screen and freshen the solder up. It's bound to repeat the symptoms.

I had this problem in my IBM PC and found it was a corroded diode (http://www.classic-computers.org.nz/blog/2008-8-23-repairing%20an%20IBM%20monitor.htm). My Mac SE/30, also started to look flaky in the video department until I resoldered a series of connector pins. It was the same symptom as the IBM...screen instability until I gave it a good whack on the side. Different cause though. Now fixed.

Take care. As I'm sure you know, voltages can approach 500V around a tube. I know how to render a Mac tube harmless but regarding others I have no idea.

Tez

leaknoil
April 13th, 2009, 09:14 AM
Take care. As I'm sure your know, voltages can approach 500V around a tube. I know how to render a Mac tube harmless but regarding others I have no idea.

Tez

Exactly why I hate messing with CRT's. Its really cramped where they put the tube and driver electronics. Sort of screwed into the top half of the case.

They didn't think that made things difficult enough. So, they placed the video connector on the exact opposite side of the system with just enough cable length to reach closed. Finally they added a fan to the crt side and screwed the ground into the chassis. "Lets see anyone work on this now!", they said and took the rest of the day off.

Seems to be ok now but, I can't find anything useful to transfer on the disks so far. I found WordStar and MailMerge. That brought back memories. Mostly painful ones though.

Dr_Acula
April 13th, 2009, 09:27 PM
I've just been reading about this model - nice computer. So - you have video working now and are going through all the disks? I'd be hoping someone here has disk drives the same as yours and can post you a disk. Sorry, I don't. The problem is - how do you get comms software across in order to get comms going? For the N8VEM board we cheat and put xmodem in the eprom along with cp/m and a format program. Format and xmodem are sort of the bare minimum to get data over. Mind you, back through the whole 1980's I don't think I ever got a cp/m computer talking to another one. Have you got essential cp/m files - eg Load, stat, asm etc?

Terry Yager
April 13th, 2009, 10:58 PM
Mind you, back through the whole 1980's I don't think I ever got a cp/m computer talking to another one.

Did you ever try a program called 'NSWEEP'? You can find it on the W/C CDROM, filename NSWP20x.ARK or similar. It's the only thing I ever got working, but only for textfiles. Never did figger out binary transfers, although it's supposedly possible. (I ain't the shiniest coin in the piggy bank).
After you get used to it, you'll consider it one of the 'essential' CP/M programs as well (especially if working on a hard drive or different user areas).
--T

Dr_Acula
April 14th, 2009, 07:03 AM
No, never saw that one. I'll look it up. Of course, in the 2000s I've got cp/m computers talking to each other using xmodem. And tonight - big breakthrough, I've just managed to telnet into my cp/m board and transfer some big files back and forth including binary files. A few cunning tricks - choose the right telnet program and also disable telnet protocol checking. I'll write it up and get the board back online hopefully in the next few days.

The hard bit is getting the first program onto the computer. I *suppose* if one had a text editor and one had asm.com or m80 or some sort of 8080 or z80 compiler, one could hand code in xmodem and then assemble it. But boy would that be tedious. Maybe one could write a very small program that reads the serial port and types that onto the screen as if you hit a key. Then you could 'type' in a program from a PC. What sort of disk drive does the northstar use?

leaknoil
April 14th, 2009, 07:55 AM
The guy who gave me the system just emailed saying he found a pile of more disks including some games even. Hopefully there is something there. Going to pick them up this weekend.

From what I understand Northstar sold a network card for these. I'm sure it was something very proprietary but, supposedly it worked pretty well. Gave them an advantage over IBM at the time.

I'm thinking this might be one http://cgi.ebay.com/NorthStar-Advantage-Mystery-Board_W0QQitemZ200318800339QQ

chuckcmagee
April 14th, 2009, 08:22 AM
Hey, I think you could be right on that Vintagemicros mystery card on ebay. Good luck finding any software tho. Maybe something in that "to be picked up" pile.

afausak
April 18th, 2009, 02:27 PM
Check to see if a glow is evident in the back of the tube. If not, test the voltages (around 12v). If there is, look for a bad trace or diode near the CRT driver.

atf



I picked up a Advantage 8/16 this weekend from someone that used to work for Northstar. He told me it hadn't been turned on in 20 years and well it looked like it. Its still in excellent condition but, needed some serious cleaning.

Anyway, made it all new looking and reseated everything that could be reseated. All looks good. Power it up and get one beep and nothing more. Fuse in the power socket blew. Luckily it had a spare in it. Swap them and now it beeps and lights up and will even load a disk when I randomly mash keys but, the screen shows nothing. Nothing changes when I adjust the brightness knob in the back. It doesn't seem like the tube is being powered or may be dead. No typical CRT sounds and doesn't feel warm or make the hair on my arms stand up when pressed against it.

Dead tube ? I know nothing about the CRT side of old computers. Honestly I dont like messing with them. Welcome to any suggestions. Double checked all connections and they appear fine.

He also gave me what look to be original factory blue print schematics for the thing. Has hand written corrections on it and is an actual blueprint not something out of a manual. I guess he designed the production floor for the Advantage there. Also the internal telephone directory for Northstar in 1984 which is kind of cool. That and 50lbs of other docs. I'd love to get this working.

leaknoil
April 19th, 2009, 02:51 PM
While I haven't solved the transfer issue yet I did take some pictures and found the demo disk. I remember watching this demo run over and over as a kid in my local ComputerLand and thinking it would be so amazing for games. The graphics were such a waste for boring 'business' stuff.