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NeXT 17" Color
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jvernet



Joined: 02 Jan 2006
Posts: 78

PostPosted: Fri Mar 10, 2006 8:06 am    Post subject: NeXT 17" Color Reply with quote

Hi,

I have a N4001 NeXT 17" Fimi Color Monitor, non working. It doesn't show anything, i do not have the usual sound when the NeXTstation goes up.
i've checked the fuse, OK.
Cable, NSLab and Soundbox works very well with an SGI monitor, also.

Does anybody have any idea ? Can I find a service manual for this monitor ?

I can give it to a friend who can try to fix it, but it's not a VGA adapter, so I need to also give him my NSLab/Soundbox, but I really don't want Wink.

is there a pinout assignement for the 13w3 connector somewhere ?


Thanks.


Jerome
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brams



Joined: 27 Dec 2005
Posts: 511
Location: Blackburn, England

PostPosted: Fri Mar 10, 2006 9:24 am    Post subject: Reply with quote

Here is what Google came up with:

http://pinouts.ru/data/nextcolor_pinout.shtml

It's mentioned in the NeXT FAQ here:

http://www.faqs.org/faqs/NeXT-FAQ/

AFAIK it's a Philips monitor made in Italy so it might be an idea to broaden your scope by looking for schematics for similar Philips monitors of similar vintage.

Best thing I ever did with my Fimi was get rid of it, Fimi monitors are not the best.

If you Google the 13w3 connector you should find plenty of info, AFAIK it's basically the same as SGI with Sync on Green, though 13w3, Sun is different and uses C/sync or H/sync or something.

Probably the rest of the small pins either do nothing or are for things like brightness control from the KB/Soundbox.
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idylukewild



Joined: 28 Feb 2006
Posts: 121
Location: Baltimore, Maryland, U.S.A.

PostPosted: Sat Mar 11, 2006 6:32 am    Post subject: If you feel able to... Reply with quote

I got help from the following website when fixing my FIMI:
http://repairfaq.ece.drexel.edu/sam/monfaq.htm

It is not FIMI specific, but I was able to use a heat-gun to
track down the cause of a strange 'vertical squashed' that
I was able to track down to a single electrolytic capacitor
that had gone bad. I replaced the cap and the monitor
works perfectly now.

He has troubleshooting advice for various levels of 'deadness',
perhaps you could try his techniques. When I first encountered
my problem with my FIMI I searched the web for schematics
without result.

Hope this helps.
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idylukewild



Joined: 28 Feb 2006
Posts: 121
Location: Baltimore, Maryland, U.S.A.

PostPosted: Sat Mar 25, 2006 6:49 pm    Post subject: Reply with quote

I've just repaired another NeXT monitor using the complete and simple instructions on http://repairfaq.ece.drexel.edu/sam/monfaq.htm.

I thought it might help others to post how I went about another successful repair of a NeXT monitor. Keep in mind I don't own any schematics or manuals for any of my three monitors (a 17" FIMI color, a 21" Hitachi color and an N400A mono). I'm sure the technique I used to repair the two color monitors could be used on mono monitors as well.

The monitor I just repaired is a 21" N4005 made in 1991. After I got the monitor in the mail a week or so ago, I powered it up and saw the following:



Obviously, there was something wrong. Having had success repairing the 17" monitor I decided to look to instructions on the website given above and figured out that what I was seeing was a "Symptoms of Some Common Deflection Problems" -type problem. It looked most like "horizontal sync lost" (actually, it looked like a rather extreme case of horizontal sync lost). I then used the same technique I used on the 17" monitor to find a failing electrolytic capacitor. I "cold-sprayed" indevidual capacitors in the horizontal sync section of the monitor electronics while looking at the image of the log-on screen until the image changed when a capacitor was cooled.



By using the cold-spray I was able to get a log-on image like the following:



So it was looking better. I actually ended up replacing two bad capacitors to get the monitor back into perfect shape, as shown below:



When I went to the electronics store for the replacement capacitors, I used caps with a little bit higher voltage and/or temperature rating. I don't know if it is needed, but it couldn't hurt and didn't cost any more. The replacement capacitors cost $0.59 each.

I had never tried to repair a monitor or tv or any other crt device before I attempted the repairs of the 17" and 21" monitors. I was happy it turned out so well. If it were not for the website noted above, I would not have had the slightest idea what to do. Evidently, electrolytic capacitor failure is common in old monitors. It is also fairly simple to diagnose and repair. I've downloaded the html version of the website noted above so I don't even have to go online to us it. I can see the advantages to adapting modern LCD monitors for use on NeXT machines, so I'm thinking of doing that eventually because no CRT will last forever. But in the meantime, it's kind of cool to use the original black hardware.



Disclaimer: Keep in mind you can kill or maim yourself by opening up a monitor and fooling with it. If you do so, you do it at your own risk Exclamation Exclamation Exclamation
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brams



Joined: 27 Dec 2005
Posts: 511
Location: Blackburn, England

PostPosted: Sun Mar 26, 2006 12:03 am    Post subject: Reply with quote

Congratulations!, I'm impressed by this, thanks for showing the pics they're great.

How did you know where the horizontal sync section of the monitor was, I find this is the part that usually confuses me.

brams
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idylukewild



Joined: 28 Feb 2006
Posts: 121
Location: Baltimore, Maryland, U.S.A.

PostPosted: Sun Mar 26, 2006 12:05 pm    Post subject: Reply with quote

Good point! I forgot to include a key bit about working without a schematic. It turns out that once you have diagnosed the problem as being with a specific function (i.e.; with the vertical control for my FIMI and with the sync control for my Hitachi), you can find the location of the electronics responsible by looking for clues. For the 'vertical squashed' problem with my FIMI I found the vertical adjust potentiometers (little single turn pots that can be adjusted from outside the cage around the monitor) were all located at one section of one card in the monitor. I then 'cold-sprayed' the ten or so electrolytics in that area. Within seconds I had found the one bad capacitor.

For the 21" monitor there was a horizontal sync adjust pot deep within the monitor. I could not get the image on the screen to change by applying cold spray in that section. However, I thought that it might be worth trying to look for the sync circuitry near the 'green, blue, red' video inputs to the monitor. I used the cold spray all over that board, and found the location of the bad capacitors. Later I realized that the location was very close to the green video input, which makes sense since the NeXT monitors are 'sync on green'. I could also see that the faulty capacitors appeared to be in a location of circuitry that wasn't duplicated for the blue or red inputs. The whole 'cold spray' process goes very quickly and took just a few minutes before I saw a change on the monitor screen. It is a very satisfying diagnostic technique.

One other thing I didn't mention is that the bad capacitor can be found by watching image on the screen get worse with application of cold spray. That's how I found the bad capacitor in the FIMI. As the photos show, the image improved with cold spray for the Hitachi. For all of the rest of the circuitry I saw 'no change' with the application of the cold spray.
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brams



Joined: 27 Dec 2005
Posts: 511
Location: Blackburn, England

PostPosted: Sun Mar 26, 2006 12:39 pm    Post subject: Reply with quote

Thanks for that. Electrolytics dry out with age and then the values start to drift. With regard to Hi-Fi amplifiers, most people reckon that a decent amp that's got lots of electrolytics in will need re-capping every 10 years or even sooner if they get lots of use or run hot like in class A. I know I have to re-cap both my Marantz amps shortly. Chances are that on an old CRT's like these are now, it would probably be best to re-cap the whole thing.

In the photos, I think I can see 3 BNC's for RGB, are they on the back of your 21" NeXT as well as 13w3?, I'm pretty sure my 21" has only got 13w3.

Thanks
Regards
Mick Bramley
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idylukewild



Joined: 28 Feb 2006
Posts: 121
Location: Baltimore, Maryland, U.S.A.

PostPosted: Sun Mar 26, 2006 6:28 pm    Post subject: Reply with quote

I thought it was very odd that there was no 13w3 connector on my N4005, but the three BNC's are all that is there. Luckily the person who provided me with the monitor included the NeXT 13w3-BNC addaptor which fits on the end of the 13w3 cable from my NeXTstation y-cable. It might be possible to correlate the lack of a 13w3 input with the serial number, which for my N4005 is "ABH Y1E000498". The date of manufacture is May, 1991.

Thanks for your comments and questions. It's good to hear from others interested in preservation and restoration of old hardware.

Luke Goembel
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blackcube



Joined: 27 Dec 2005
Posts: 164
Location: Sherman, Texas USA

PostPosted: Mon Mar 27, 2006 3:42 pm    Post subject: Reply with quote

idylukewild wrote:
I thought it was very odd that there was no 13w3 connector on my N4005, but the three BNC's are all that is there. Luckily the person who provided me with the monitor included the NeXT 13w3-BNC addaptor which fits on the end of the 13w3 cable from my NeXTstation y-cable. It might be possible to correlate the lack of a 13w3 input with the serial number, which for my N4005 is "ABH Y1E000498". The date of manufacture is May, 1991.

Thanks for your comments and questions. It's good to hear from others interested in preservation and restoration of old hardware.

Luke Goembel


Luke, the N4005'sa were built in two versions. One had three BNC's, the other had a 13w3 connector. Before you bought that one, I had three. One is the 13w3 version, two had the three BNC's. The other BNC verson monitor has a big red sticker marked "Engineering Sample - not for resale" on the back and as I recall, it has a 1990 date on it.

Sorry that that one had bad caps. None of them have been fired up for over two years. All of mine may be bad by now.
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idylukewild



Joined: 28 Feb 2006
Posts: 121
Location: Baltimore, Maryland, U.S.A.

PostPosted: Mon Mar 27, 2006 5:48 pm    Post subject: Reply with quote

James-

That explains it! I think it's really cool you have an engineering version of the monitor. I'm very happy with the monitor you sold me. The couple of hours I spent repairing it was worth it. I've got a nice big beautiful display now. Probably everybody will have to do some re-capping eventually. I noticed some electrolytics on my '040 motherboard and am wondering if they'll need replacing some day! Whenever I have electronics built I try to avoid electrolytics - but there is almost no way to avoid them because the capacitance is so high for such a small package. For the space hardware I build electrolytics are not allowed - they explode/leak in a vacuum.

Luke
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Nightengale



Joined: 04 Jan 2006
Posts: 152
Location: SD CA

PostPosted: Tue Mar 28, 2006 5:48 pm    Post subject: Reply with quote

Very nice to read about the repair exploits here. I used to repair monitors in my old job, I found it to be fun too.

Any chance you could e-mail me that html page for the repair faqs? The site seems to be down right now.

donaldrockNOSPAMPLEASE@hotmail.com, if you get time and are willing to send the file, just remove the obvious in my e-mail address.

Don
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idylukewild



Joined: 28 Feb 2006
Posts: 121
Location: Baltimore, Maryland, U.S.A.

PostPosted: Tue Mar 28, 2006 6:49 pm    Post subject: Reply with quote

Don-

I just e-mailed the html file and a few GIF files. Hope this works.

Luke
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fidel



Joined: 28 Feb 2006
Posts: 17
Location: Montréal

PostPosted: Tue Mar 28, 2006 10:13 pm    Post subject: Reply with quote

It may be that you want to start at the Galactic homepage:

http://www.repairfaq.org/

then hit the TOC:

http://www.repairfaq.org/REPAIR/F_Repair.html

then the monitors FAQ:

http://www.repairfaq.org/sam/monfaq.htm[/i]
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Nightengale



Joined: 04 Jan 2006
Posts: 152
Location: SD CA

PostPosted: Wed Mar 29, 2006 10:04 am    Post subject: Reply with quote

Yes Fidel, that did work. I feel like such a dummy Rolling Eyes
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da9000



Joined: 30 Sep 2006
Posts: 387
Location: Silicon Valley

PostPosted: Wed May 02, 2007 8:57 am    Post subject: Reply with quote

I just wanted to say, after reading this old thread:

Good job Luke! I'm really happy to hear of the cold spray technique!!! Because I had no idea about it! Now I can't wait to get a bad monitor to fix Smile))) (ok, not that badly!)

I assume that compressed air spray won't help, right? I need the real cold spray stuff, yea?


Anyways, a couple more things from my 'dead caps' experiences:

3 more ways to spot bad caps:

1) If they have gone *really* bad and bulged (usually at the top, but sometimes at the bottom). So basically: the top should be flat, but it's not. The bottom/side should be straight, but it's not, but slightly conical.

2) Leakage. Some will leak their electrolyte (almost always at the bottom where the leads are), and you'll be able to see the almost-liquid substance on the board. Take care to clean it up, because it will corrode nearby electronics killing the board! A good example is the electrolytics in the Amiga (at least on 600, 1200, 4000) sound circuits: http://amiga.serveftp.net/audio_repair.html

3) Loose caps. With your thumb or finger try to wiggle the capacitor. If it wiggles too much or moves too much, then it might be bad. It might not have leaked, or bulged, but it's getting there. The normal condition is for the cap to feel sturdy. One last reason could be a bad solder, but that's not as usual and feels a bit different: the wiggle "feels" as if coming from a lower section (motherboard)


Finally, I agree with brams: if you find a bad cap, you might want to consider re-cap'ing all of them. And Luke alluded to this: the caps on the NeXT motherboards. I'm worried about both the SMD and non-SMD ones, especially since the SMD on the Amigas leak and kill the circuits...

PS. Someone on here mentioned a dead monitor recently. I don't recall who. Perhaps he should be pointed to this thread.
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