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Sharkonwheels
April 12th, 2008, 12:02 PM
OK - all text is like scrunched down into the center - adjustments do nothing.

Druid - can ya take a look at the manual, and see if you can see anything I can look at? It even has Osc waveforms to look at using tp's on the crt board.

tech manual is at:

http://www.zorba.z80.de/files/telcon/zorbatech.pdf

mucho thanks - I'd like to get the internal display going on this puppy.
And yes, it's the one Erik mentioned on here a few weeks ago that someone posted for sale.

T

Druid6900
April 12th, 2008, 02:05 PM
Tony, can you post a quick picture of the screen so I can see exactly what it's doing?

Sharkonwheels
April 12th, 2008, 03:03 PM
http://i92.photobucket.com/albums/l33/Sharkonwheels/Zorba/IMG_1152.jpg



http://i92.photobucket.com/albums/l33/Sharkonwheels/Zorba/IMG_1151.jpg

And very few seconds, it flashes about 1" tall worth of a piece of the boot-up ZORBA logo...


T

Druid6900
April 12th, 2008, 08:17 PM
Ok, I'll go through the vertical deflection section of the manual tomorrow, hopefully, and get you to check a few things.

You have life insurance, right? :)

Sharkonwheels
April 12th, 2008, 09:11 PM
This one happens to have a video deflection IC - TDA1170S.

I thought you had mentioned deflection before...

Here's datasheet for a compatible STMicro unit:

http://www.ortodoxism.ro/datasheets/SGSThomsonMicroelectronics/mXyzxsyv.pdf

Yes, I have insurance - I also am very aware of the high-voltages present, and I also have the plastic tools, and I think I can deal with it...

T

Druid6900
April 13th, 2008, 11:18 AM
Ok, if it has a TDA1170 in it, it's a 90% probability that's the problem. Those things popped like dried corn in boiling oil.

The other 10% would be the transistor that this chip drives. If it's gone, the 1170 probably is too, but, if the 1170 is shot, it shouldn't affect the transistor.

After replacing the component(s), you'll probably have to adjust the vertical size and linearity to accomodate the differences in output.

Sharkonwheels
April 13th, 2008, 01:00 PM
Much appreciated...
I mentioned the TDA1170S, because it's legs are dark, bordering on black-coated. Just looked suspicious.

I'm going to look now, but did you happen to notice which trans it drives?
Cna;t hurt to change both - I only have shipping $$ invested in the machine, and it came with a WEALTH of docs - 40lbs of manuals and disks, and even the source code for CBIOS, boot rom, utilities like format, etc...


T

Druid6900
April 13th, 2008, 07:31 PM
I've seen that on a lot of ICs, but it's probably not indicative of damage, just crud. If it got that hot, the IC most likely would have exploded from the gas pressure inside.

No, I didn't notice, Tony, but when you take the board out and look at the traces, it'll be a good sized transistor, either a metal one or one with a heat-sink.

Sharkonwheels
April 13th, 2008, 11:51 PM
Well, there's one huge Q on there, but it's not listed in the parts list (just says "Trans Assy" which isn't helpful). It's too blurry on the schematic scan to read the Q type (manual page 4-2, PDF page 83) but then again, that Q is on the Horiz Drive output, which isn't in question (yet), right?

Anyone got a paper manual/schematics for the Zorba?


T

Sharkonwheels
April 14th, 2008, 01:23 PM
Going to pick up the part tomorrow morning.
I noticed that the Osborne 1 video board uses the same chip as well, so I am
pickup up a second chip for the parts bin. ;) Wonder if the Exec uses the same thing ;)

Ordering a few of the other Q's as well, seeing as they are pennies each - 2N3904, 2N3905, 2N3053A.

T

Druid6900
April 14th, 2008, 07:24 PM
It very well may use the same IC, they were very popular back then. It was one IC that we were always ordering and the minimum on-hand was 20 or so.

Sharkonwheels
April 15th, 2008, 11:39 AM
Got the TDA1170S chip today - NTE still actively makes/sells them - NTE1289 if'n ya needed any... $11.63. Found a nice place in Miramar, FL that actually had (2) in stock (bought both) and they also had durn near all the other Q' I needed.

I will try swapping it out tonight, and see what happens - cross your fingers!


T

Sharkonwheels
April 15th, 2008, 05:29 PM
No dice.... same exact thing with the new 1170S...
On the schematic, I don't see any Q's in the vertical drive section.
Am I missing something?

T

Sharkonwheels
April 16th, 2008, 11:58 AM
Dropped it off at an electronics repair shop this AM, along with the PDF tech manual with it's schematics....

Guy seems competent enough, and a nice guy to boot.
So, we shall see....

If he gets this working, I'll take one of the Executives over there, which I have the full hardware technical manual set, and with the tech manual+schematics see if he can get the CRT working on that as well...


T

Druid6900
April 16th, 2008, 12:09 PM
No dice.... same exact thing with the new 1170S...
On the schematic, I don't see any Q's in the vertical drive section.
Am I missing something?

T

No, you aren't missing anything, I was, sleep. LOL

I was looking at the horizontal drive section when I mentioned the transistors and it never even dawned on me that, with the 1170, they aren't needed.

Since you've taken it into the shop, I won't mention what to play around with next. Hopefully, it is the vertical height or linearity controls, because, after that, it's most likely the yoke.

Sharkonwheels
April 16th, 2008, 01:31 PM
I played with the VL and Height, and it made no diff.

T

Sharkonwheels
April 23rd, 2008, 12:33 PM
OK - $100 bill to fix it. I forgot what he said he had to fix, but he said it's working fine now. Considering I paid only shipping (about $50-60) for it, I think it's worth it. All the original docs+disks are with it, as well as cables, and even the original purchase receipt!

I'll take pics when I re-assemble it!

Next up - Osborne Executive....

Wish the thing luck - that one gives nothing on the CRT!


T

Terry Yager
April 23rd, 2008, 07:19 PM
Be sure to share details after you remember.

--T

Sharkonwheels
April 23rd, 2008, 08:05 PM
Generic - receipt says:repair vertical assembly, replace defective components"

Parts replaced, shows HM3815T60. Might be the huge-@ss transistor that
I couldn't really see an ID on... Dunno....that number shows nothing on the NTE CrossReference tool (free at nteinc.com, if'n you are so inclined)

Guy was super-cool, and I'm glad I met him. been there for nearly 20 years, literally 5 minutes away. Closes at 6pm, I showed up at 6:01, and we talked BS until 7:45pm.

I suppose anyone down south who needs something along these types fixed, and has noone local, I can now strongly recommend him.

Bob
Picture Perfect
Pembroke Pines, FL
954-435-5868

I guess it's only worth it if you're but a few hunner'd miles away...
After that, shipping kills....


T

Sharkonwheels
April 23rd, 2008, 08:15 PM
Here she is working:

http://i92.photobucket.com/albums/l33/Sharkonwheels/Zorba/IMG_1170.jpg


And here's a top-shot. The ribbon cable is the inter-connect between the SWP Co-Power-88 board, and it's Z80 interface board. You can just barely see the board, where the ribbon cable connects to it with the white connector. This has the original style 128kb board, but has the 128kb add-on for 25kb total. It is also, as on Kaypros and such, usable as a CP/M 250kb RAMDisk. And DANG! Are those canon FDD's loud as all get-out!

http://i92.photobucket.com/albums/l33/Sharkonwheels/Zorba/IMG_1172.jpg



I'll put up a couple more tomorrow, when it's all buttoned up.
Tomorrow I take the no-video Executive to him, along with a working one for reference, and the original tech manual which has the analog board schematics. Hopefully he can fix that one, and I can fleaBay it. 3 Execs is MORE than enough, thank you!


T

Druid6900
April 24th, 2008, 11:34 AM
Yeah, sure is easier troubleshooting something when it's right there in front of you rather than 1500 miles away :)