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New guy reviving a couple of Kaypro 2Xs and implementing a floppy adapter

k6whp

k6whp

Experienced Member
Joined
Mar 1, 2014
Messages
71
I am returning after a time and unsure if this thread will be moderated for the ten posts (not that it matters) so I will state problem as completely as possible and wait for some responses to digest.

Background:
I have two Kaypro 2X units and one Kaypro 1 unit. The Kaypro 1 unit is functional but, alas, the 2X units have disk drive problems. All of these units were stored in a clean, cool, dry moderate environment.

Unit #1 (as I shall designate it) I have owned since essentially 1984 and used up until 1987. About three years ago, I got it out and noted it had problems. Succinctly, the video was distorted and it would not boot from the A: drive. Eventually, the A: drive "woke up" and it booted. The distorted video was traced down to a couple of bad caps on the video board. These were replaced and the video restored. The unit was placed back in storage until it was pulled out last week (early March 2022) and tested. Now the A: drive will not boot despite being fed the "original" Kaypro master disks or its CP/M disk copies I made to work with it three years ago and I have tested on Unit #2.

Unit #2 (similarly designated) boots from drive A: but drive B: has gradually "faded" into malfunction. That is, in copying some diskettes for a friend, I noticed a grinding sound like the drive was laboring. Eventually, the drive became in reliable --e.g. failed to work.

Both of the 2X units have the Epson SD-521 drives in them.

Below are some pictures of the two units marked appropriately.

Objectives
I should like to:

(1) Revive the two 2X machines such that the A: drive boots on #1 and that the B: drive functions correctly. Any guidance pointing to a thread or source onhow to clean, adjust, and calibrate the SD-521 drives appreciated. Have searched but only found fragmentary info.

(2) Failing that I would like to see if I can implement a USB floppy controller for drive A: and use the two good drives as B: drives. Either the HCX or GoTek controllers would be satisfactory. I note that the

(3) Ultimately, I would like to convert the Kaypro 1 to use a USB floppy disk controller as well.

(4) BUT BEFORE I DO ANY OF THAT, I do not want to pile a heap of stuff on you all. I have been wading through some of the threads here and elsewhere and, if you can point me to any sources of info where I can educate myself, it would be appreciated. With references like that, I can do the research and come back here to ask "byte size" (Sorry) questions and add to my knowledge.

Mainly just appreciate any guidance to get me off the ground. Much thanks in advance.

two Kaypros.jpg unit #1 overview.jpg SD-521 floppy 1.jpgunit #2 mother board.jpg
 
Hello, @k6whp !

I don’t know a ton about Kaypros, personally, but I’ll see what I can do to help.

First, here is a thread on the Epson SD-521 drive, where it is pointed out that the Epson QX-10 service manual has service information on the drive:

Second, since the SD-521 is a standard Shugart-interface floppy drive, replacing it with a disk emulator, like the FlashFloppy-based Gotek unit, should be quite easy. You’ll just need to jumper the drive appropriately, since the Kaypro uses real Shugart ds0, ds1, etc. settings instead of the PC’s twisted cable:
github.com

GitHub - keirf/flashfloppy: Floppy drive emulator for Gotek hardware

Floppy drive emulator for Gotek hardware. Contribute to keirf/flashfloppy development by creating an account on GitHub.
github.com github.com

You can buy pre-flashed Gotek units on ebay, or flash your own.

Hope that this helps a bit.

- Alex
 
One comment about the EPROM with the exposed window. You should immediately cover that - ideally with a foil sticker (I have heard reports of "white" paper labels bleeding enough light to eventually erase the EPROM). But, the Kaypro case should have kept (most) light out. Still, you want to cover that. Long term exposure to even a little light can "fade" those EPROMs. If you don't have a programmer, you may want to look into getting one. You probably want to read the unlabeled EPROM and try to identify it's contents, and then validate its integrity.
 
My own experience with EPSON drives: I have seen the grease harden to the point that things start malfunctioning. I guess this is probably not specific to EPSON drives. I especially saw it for the push-button eject mechanism, but I also believe the screw-drive on the stepper motor is susceptible. I VERY CAREFULLY applied tiny drops of light machine oil, using a syringe, to key parts and operated them to spread the oil and soften the grease. You must make certain that the oil never gets on anything that can contact the floppy - especially the floppy media (like the heads).
 
ajacocks said:
Hello, @k6whp !

I don’t know a ton about Kaypros, personally, but I’ll see what I can do to help.

First, here is a thread on the Epson SD-521 drive, where it is pointed out that the Epson QX-10 service manual has service information on the drive:

Second, since the SD-521 is a standard Shugart-interface floppy drive, replacing it with a disk emulator, like the FlashFloppy-based Gotek unit, should be quite easy. You’ll just need to jumper the drive appropriately, since the Kaypro uses real Shugart ds0, ds1, etc. settings instead of the PC’s twisted cable:
github.com

GitHub - keirf/flashfloppy: Floppy drive emulator for Gotek hardware

Floppy drive emulator for Gotek hardware. Contribute to keirf/flashfloppy development by creating an account on GitHub.
github.com github.com

You can buy pre-flashed Gotek units on ebay, or flash your own.

Hope that this helps a bit.

- Alex
Click to expand...
Alex, and Doug,

Much thanks for the link and advice. I was able to track down the manual and, while it refers to the SD -321. I assume that they are "close enough for government work and the level of detail is stupendous! After much research and reading and an evaluation As I evaluate the status, I will probably press ahead along the GoTek path and see if I can get one machine working and then, with the FDDs left over, see if I can breathe life into the second one.

As I mentioned, I most probably have one good SD-521 that can be used as a B: drive in the converted machine.

As far as the uncovered EPROM is concerned, it's probably been erased a I have had the cover off the 2X for three-four days now. I have covered it, however. (Barn door, horse, etc.)

So I will be looking into the EPROM burner all though I am out to sea on this. Would appreciate any recommendations to handle this specific task, the source of the Kaypro firmware/data to burn into this chip, etc.

More questions on the GotTek installation to follow! Appreciate your help!

WHP

I have
 
WHP,

The EPROM definitely wouldn't have been erased that quickly. It's definitely worth putting a sticker on it, but I've had plenty of machines with them missing for a long time, with no particular ill effects.

Has anyone tried to erase and EPROM, on purpose, with the sun? I have; it takes a loooooong time (I've never succeeded!).

Quoting from the well explained and tested blog entry here:

Depending on your atmospheric conditions, weather, latitude and obstructions, the amount of “peak sun hours” you get in a day can vary, as can the UV content. In my case, I would estimate about 3 PSH per day because of obstructions, so the total dose is about 13.791mJ/cm²/day. This means that in one second under the 4W eraser tube, we get the same amount of usable UV as you would expect for a day under sunlight. To erase a 15W.sec/cm² EPROM would take 1087 days (2.978 years) or twice as long for a 30W.sec/cm².
Click to expand...

So, basically, don't worry about it; putting a sticker on is good practice, but unless you live in a house with a _lot_ of grow lights, tanning beds, or black lights, you EPROMs aren't going to get spontaneously erased.

- Alex
 
I have a TL866ii which I've only used on modern EEPROM/FLASH devices. There are some legacy EPROMs it will work with, so it may be possible to re-burn the EPROM you have. I also think there are modern EEPROMs that are pin/socket compatible with those vintage parts - they are not programmer-compatible, but if you only need it to work in the Kaypro that would be OK. In the old days I built/programmed a couple [E]PROM programmers but that has all been lost from memory as well as workbench.
 
And, Alex is correct - it takes a long time to completely erase the EPROM with ambient light. The concern would be whether there is any "fading", light exposure combined with general age (30+ years). I don't have any scientific support for that, but have heard of old EPROMs showing up bad/erased unexpectedly. As I recall, the EPROMs hold their programming based on the charge on a capacitor - that just sounds transient, at least when you talk about decades or centuries.
 
Dave and Alex,

So then it sounds like things might be OK. Of the two units I have, the one that boots OK (unit #1 from above) is the one with the exposed EPROM and its symptoms are that it does not boot, period. Unit #2 is the one that WILL boot but has the "faded" B: drive. Note that they are BOTH 2X units and pretty close to identical; it turns out I can can have a lot of fun trouble shooting them -- assuming that they are essentially the same models.

I propose to:

(1) Swap the unit #1 board into the unit #2 box and see if unit #2 and see if it boots. Probably good indication if the EPROM is OK.

(2) Move drive A: on the unit #2 box to the unit #1 box and return the unit #1 board to the unit #1 box. If it boots then it means that the problem was with the unit #2 A: drive and I could swap in the drives (jumpering and plugging the resistor block appropriately) and see what works and what does not.

Anyway, I could go on but at this point, the one machine that looks most promising will get the GoTek and a good drive in B: and, if possible, the remaining machine will get upgraded next if I have a decent floppy left over.

Why do I sound too overly optimistic?

Exit question: the 3V soldered in NiMH battery has given up the ghost 0.25 VDC) so are things hosed or what? One is on order and the iron is heating up as we speak!

Thank you both for the help!
 
The battery only provides standby power to the RTC chip, so not really essential for operation. The one with exposed EPROM has the RTC and HDD hardware populated, but it's unclear how much of that was used. The ROM may or may not be the standard 2X 81-292 (which cannot boot the HDD, AFAIK). The RTC is only usable through special programs, as CP/M 2.2 had no concept of "system time".
 
durgadas311 said:
The battery only provides standby power to the RTC chip, so not really essential for operation. The one with exposed EPROM has the RTC and HDD hardware populated, but it's unclear how much of that was used. The ROM may or may not be the standard 2X 81-292 (which cannot boot the HDD, AFAIK). The RTC is only usable through special programs, as CP/M 2.2 had no concept of "system time".
Click to expand...
Doug,

Though so. Thanks!

The "other" board's EPROM is labeled "82-192" so there's another loose thread tied up. Willing to bet that the exposed one is one of them. Anyway, I will proceed to swap boards and see what's what as I head down towards the GoTek path.

Thanks you and Alex for getting me started in the right direction!

Bill (k6whp is my amateur radio call sign)
 
Gentlemen,

I pushed on a little further and wanted to comment/ask some questions about what was observed. On the KayPro 2X that had the good boot A: drive (unit #2), I was able to swap the unit #1 mother board (the one with the uncovered EPROM) and it performed identically to the original motherboard. So I guess the EPROM was not erased.

In testing the two original FDDs (both with the original mother board and the "other" mother board), I wanted to determine whether the diskettes I was using were bad/differently formatted or if it was the B: drive. I put in a boot disk and did a DIR command which displayed the A: directory. I then moved the disk to the B: drive without doing anything else and did a DIR B: command which yielded this:

DIR test.jpg

Note the original DIR command and then the DIR B: command results. Curious, I rebooted the disk and ran MFDISK to look at what an INQUIRE command would reveal. Here's is what it said about the A: drive, which is what you might expect:

FDD mfdisk 1.jpg

Then, moving the SAME DISK to B: and doing an INQUIRE, I got this, which is what I did not expect.

FDD mfdisk 2.jpg

Alas, I am in a situation where I have little else but the limited utilities and some diskettes of questionable formats. I will swap the A: FDD for with the B: FDD and see what happens. And I will, of course , be mindful of swapping te the resistor block as well as the appropriate jumpering.

But, in addition to what's happening here, I would ask if I should try to get this situation straightened out or should I just start the GoTek mod and not waste the time?

Thanks in advance.

Bill
 
Bill,

I'd guess that the second drive is out of alignment or dirty. There is a ton of information on various floppy technologies on Herb Johnson's site:


I'd first start with a thorough cleaning and lubrication of the drive. A procedure for doing that is here:

dfarq.homeip.net

5.25 floppy drive maintenance

5.25 floppy drive maintenance isn't overly difficult. With some isopropyl alcohol, silicone lubricant, and some cotton swabs, you can be back in business.
dfarq.homeip.net dfarq.homeip.net

If you can't get it working, you might want to ask if there is someone near you who could help. I'm not sure where in the country you are, but if you share that, maybe someone will offer.

- Alex
 
Thanks! I'll bet that's the problem with the other 2X as well. And it would be great to ensure the FDDs actually work so as to eliminate variables when the GoTek conversion is done.

..I am in Fountain Valley. It's a small suburb near the ocean about ten miles down from Disneyland.

Appreciate the assistance and prompt reply!

:)

Bill. k6whp
 
k6whp said:
Thanks! I'll bet that's the problem with the other 2X as well. And it would be great to ensure the FDDs actually work so as to eliminate variables when the GoTek conversion is done.

..I am in Fountain Valley. It's a small suburb near the ocean about ten miles down from Disneyland.

Appreciate the assistance and prompt reply!

:)

Bill. k6whp
Click to expand...
..in Southern California; not Florida!

;)
 
There is probably nothing wrong with the Floppy Drives. Your method of randomly swapping floppy's
without doing a CONTROL C (to read in the NEWLY INSERTED Floppy's Directory Entries) is the problem.
(If you do something like this and write to the NEWLY INSERTED floppy, it will clobber the Driectory
Entries on the B: Drive Floppy.

GOOD RULE OF THUMB FOR CP/M:
If you Insert a Floppy in any Drive, either RESET (REBOOT) the COMPUTER, or DO A CONTROL C
on the Keyboard to read in updated Directory Entries. Random swapping isn't tolerated. Boot from A:
and then insert floppy's in B:, do a CONTROL C: and then do the DIR B:, and then insert floppy's in B:,
do a CONTROL C: and then do the DIR B:

PM sent with Details.

Larry
 
Larry,

Just to close the loop on this, THERE WAS something wrong with the drive! I managed to get hold of a set of those old (but unused) head cleaning disk kits. They were new but the alcohol in the packets had evaporated. No problem, though. I just lightly dosed one of the diskettes and proceeded to run the drive through a quick spin. It woke up and performed fine. Spared me the (eventual) disassembly and swabbing down with a Q-tip, etc.

Just thought you and the good readers might like to know.

GoTek disk cleaning disks.jpg
 
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