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KLund1
August 15th, 2017, 07:53 PM
Hi all!
Just got a Kaypro 4. This is the first one I have had. I opened it and there is a small daughter board with a Z80B cpu and a toggle switch it going out the back of the case.
It looks like a CPU upgrade. Can some one tell me what it actually is?

I powered it up and I get only a very thin green line of text. Not like my kaypro 10 but much thinner. Like the horizontal got squished 80%. Is there any adjustment inside for this? The 2 adjustment knobs on the monitor PCB facing the back of the case do not make any changes.
many thanks

40316

krebizfan
August 15th, 2017, 08:06 PM
Is the name on the little card "Advent?" They made an 8 MHz Z-80 card.

KLund1
August 15th, 2017, 08:46 PM
Yes it dose!
many thanks for the very quick reply!!
The zilog cpu number is z8400B ps. Is this a 6mhz,or 8mhz cpu upgrade? the PCB say 0335p rev B1. any docs on this little guy?
Also will it work on my kaypro 10? It looks like a simple plug and play upgrade. I do not see any obvious soldering on the MB.
Thanks again!

krebizfan
August 15th, 2017, 09:26 PM
Docs: none that I know of.
Might be a 5 MHz or 8 MHz. If you can find an oscillator chip, it can be determined. Advent advertised both in Profiles, the Kaypro magazine. Issues are archived online. Look for Turboboard. Because of the poor OCR, it is possible that the board is detailed better in a review or Q&A column that my simple searches can't locate.
Will it work in Kaypro 10? I am not sure. The ads suggest that there is a version for the faster Z80 Kaypros but timing can be tricky and they might have done custom versions for each system.

I hope someone else will provide more information.

KLund1
August 15th, 2017, 10:13 PM
Thanks again! very good info!
I will do some searching. I did find that magazine at archive.org, but there very hard to use interface will make searching difficult.
In looking at pics of Kaypro 4's they show 1/2 height 5.25" drives. Yet the one I have has full sized 5.25" drives. The face place looks like a KP II, but the sides sat KP 4, could this be a II that had the CPU upgraded at the factory, and they put a KP4 case around it? Some sort of variant? There are only 2 port on the back, like a KP II, 1 serial, 1 parallel. (ps this unit did not come with a keyboard, so can't use that for ID. I'm using the KB 10 keyboard)

I am also stuck about the picture. I have turned all the pots on the monitor PCB, and booted each time. There is no change in the screen output. Suggestions here?
Anyone??
Thanks

JonB
August 15th, 2017, 11:46 PM
Randomly turning the pots on the monitor board is a very bad idea, because you don't know what the expected result is going to be, and you may make the image (much) worse.

You are looking for a pot labelled V-Height or similar (note, not V-LIN).

If I were you I would try and find a copy of the service manual. [Edit: http://bitsavers.informatik.uni-stuttgart.de/pdf/kaypro/1484-D_KayproTechnicalManual_Dec84.pdf]

This should show you which trimmer is the V-Height (there is normally one somewhere), then you can adjust it, knowing it is the correct one. If adjustment makes no difference, you either have a defective pot or some other part of the circuit is defective. At this point, you definitely need the schematic and possibly an oscilloscope or at the very least a multimeter.

[Edit 2: Look at section 7. There are three CRT boards shown with the trimmer pots labelled v.width / shrink vert. / vert. size respectively.]

The usual disclaimers about lethal voltages in the CRT chassis apply.

KLund1
August 16th, 2017, 11:27 AM
Thanks,
Yes I found the service manual and it had labels for the pots. After i moved one pot,I put it back to original position before changing another. I am sill alive and writing this post, so I was careful about what I touched.
I think there must be something wrong in the circuit somewhere. And that is beyond my knowledge.
Any thoughts about being able to move the CPU upgrade from the this unit to a KP10?

JonB
August 17th, 2017, 01:59 AM
Sorry, I don't know anything about the CPU upgrade board. Hopefully another member can advise you.

I see you have a lot of Atari STs. I salute you!

jaquinn
August 17th, 2017, 06:34 AM
Thanks again! very good info!
In looking at pics of Kaypro 4's they show 1/2 height 5.25" drives. Yet the one I have has full sized 5.25" drives. The face place looks like a KP II, but the sides sat KP 4, could this be a II that had the CPU upgraded at the factory, and they put a KP4 case around it? Some sort of variant? There are only 2 port on the back, like a KP II, 1 serial, 1 parallel. (ps this unit did not come with a keyboard, so can't use that for ID. I'm using the KB 10 keyboard)


There are two "Kaypro 4" models. Your motherboard photos show the same board and ROM as my "Kaypro 4/83" (sometimes called a Kaypro IV). This model has a fairly simple motherboard and full height floppy drives. (http://q7.neurotica.com/Oldtech/Kaypro/Kaypro4-83.html). There is a later Kaypro 4/84 with a different motherboard, faster CPU, different drives. (http://www.old-computers.com/museum/computer.asp?c=548).

KLund1
August 20th, 2017, 09:47 PM
Understood. Looks like I have IV.
Ok Thanks
Where to get Keypro systems disks?
There is Daves Old Computers. But those are in IMD format. It looks like a major pain to get them on disk. I have a win98se machine with 360K 5.25" drive. But I think his ImageDisk program needs DOS6.22.
So I have to download from main PC to USB portable drive. Save on from USB win win98se to c: Then boot to DOS 6.22 and run imagedisk. Isn't there a win program that can do it all?