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Re: Weekend revival

 

On 10/16/21 11:46 PM, Klyball wrote:
Replaced a bad dram , found an interesting anomaly.  It just so happened that the bad chip was bit 5 in bank 3. So I cut it out and replaced it. The problem still persisted.  After a lot of head scratches it turns out the chips for bit 5 and 6 are switched on the board . There seems to be no reason for it as all the other chips in the other banks are all in order as per schematic and chip  #. Anyway just found that odd.
It's not that uncommon; people do it occasionally to solve trace routing problems during PCB layout.

Nice recovery!

-Dave

--
Dave McGuire, AK4HZ
New Kensington, PA


Weekend revival

Grant
 

Replaced a bad dram , found an interesting anomaly.  It just so happened that the bad chip was bit 5 in bank 3. So I cut it out and replaced it. The problem still persisted.  After a lot of head scratches it turns out the chips for bit 5 and 6 are switched on the board . There seems to be no reason for it as all the other chips in the other banks are all in order as per schematic and chip  #. Anyway just found that odd.


Re: HP 9826A - 5.25" boot images

Pawel
 

Thank you, it sounds really good. Using Teledisk2hpi I prepared some .hpi LIF files, on Monday I will try to write them to disks. The only problem I see is that fdio works on Windows and doesn't work on bare DOS. Unfortunately, I have 360k floppy drive only in IBM XT (5160). However, I found LIFUTIL (https://www.keysight.com/zz/en/lib/software-detail/computer-software/lifutil--reading-keysight-lif-disks-on-msdos-1000000786epsgsud.html) which should work on MS DOS. We'll see. I used this IBM and teledisk/imagedisk/22disk for preparing floppies for non-PC computers like Osborne 1, so I'm of good cheer. :)


Re: HP 9826A - 5.25" boot images

Ansgar
 

There is a Python tool called Teledisk2hpi which in most cases can convert TD0 into HPI flat files (see https://groups.io/g/VintHPcom/files/Etc.)

You may also try using HPDir (https://hp9845.net/9845/projects/hpdir/) or Fdio (https://hp9845.net/9845/projects/fdio/) to directly write LIF images in HPI format to 5.25" floppies without further conversion. Just take care the target floppy has the capacity to hold the full data, and for SD/DD floppies that both the floppy medium and the drive are native SD/DD (HD drives can read SD/DD floppies, but cannot reliably write them, especially if there is old data on the floppy, and HD floppies do not have the same magnetic characteristics as SD/DD so may fail during read and/or write). 5.25" floppies as found in PCs are normally HD drives, but you can connect a SD/DD drive to any standard floppy controller.

-Ansgar


Re: HP 9826A - 5.25" boot images

Pawel
 

I think this video is more or less what I'm thinking about: https://www.youtube.com/watch?v=YfLJZU4zgEU


Re: HP 9826A - 5.25" boot images

Pawel
 

Regarding TD0, let's say I have boot disk ini TD0 for 3.5" drive (most of available are in 3.5" format indeed), is there a way to convert it to 5.25"? For example convertinig first into the flat file (HPI) and then to 5.25" TD0? 


Re: HP 9826A - 5.25" boot images

Anders
 

OK. Good to know. I have a NI board that i use for HPDrive.

I know that you know, but for the benefit of others:
HPI is a flat-file format that most emulators use
TD0 is an enoded format that captures the disk geometry. Such files need to be converted to flat files to be used with emuators. Instructions can be found here in this group.


Re: HP 9826A - 5.25" boot images

 

The CEC board should work, I've used one in a Win98 system Before I got a fanless XP system. Most of the 200/300 series software is in TD0 or HPI image format.

-Rik


Re: HP 9826A - 5.25" boot images

Anders
 

You ned to make sure that the chipset is supported. HPDrive is an excellent solution. Another option is www.dalton.ax/HPDisk


Re: HP 9826A - 5.25" boot images

Pawel
 

Thanks Rik, hpdrive is ultimate goal, I have on my eyes CEC PCI - 488 GPIB card, I hope it will work, however another PC is big (perhaps I can use something smaller like here https://www.youtube.com/watch?v=Sft5bT7os4E). Nevertheless it sounds like a quit big project and it's why I wanted to make something quick from embedded 5.25" floppy, like BASIC or Terminal (I'm waiting for rs232 card) therefore I'm searching for 5.25 boot floppy images.

Thanks again,
Pawel


Re: HP 9826A - 5.25" boot images

 

Pawel,

If you have a gpib board preferably a NI488 board you can use hpdrive to emulate a hp-ib disk drive with a PC.
For more information look at https://hp9845.net/9845/projects/hpdrive/

-Rik

-Rik


HP 9826A - 5.25" boot images

Pawel
 

Hi,

I have pretty HP 9000/226 with working 5.25" floppy, and I'm searching for boot disks, for example BASIC, HPL, CP/M. On hpmuseum (http://www.hpmuseum.net/exhibit.php?swc=6) there are many software images, however most of them are for 3.5" floppy and I cannot write in to 5.25" of course. Is there a method to convert 3.5" Teledisk (TD0) images to 5.25? Or is there a resource where I can find images (preferably TD0) with CP/M, BASIC and other stuff for 5..25 disk drive?

Cheers,
Pawel


Re: Cleaning Switch contacts and machanisms on HP239a Oscillator

gtracyca <gtracy@...>
 

Is there a group for HP plotters? I have a HP 750C Plus and I"m looking for drivers for it.
Thanks.,


Re: Cleaning Switch contacts and machanisms on HP239a Oscillator

gtracyca <gtracy@...>
 

At the risk of extending this thread too long.....
I used to repair 239's for HP back in the 70's.
Camolin was my go to product for cleaning the switches. Worked great, never had complaints from customers.
They were a great oscillator in their day.
By the way I was fortunate enough to meet Dave Packard personally and had a brief conversation with him....Really nice guy.
Good luck with your restoration.


Re: Cleaning Switch contacts and machanisms on HP239a Oscillator

Jack Rubin
 

Holy Poop Batman, what a name to forget!
Thanks, Steve, for the reminder.
--
Jack
www.computerarium.org


Re: Cleaning Switch contacts and machanisms on HP239a Oscillator

Steve Leibson
 

I too have used Deoxit successfully. I've used it since 1986, when I wrote an article about contact cleaners for EDN. Back then, it was called Cramolin and came in blue and red. Still have some of that. These days, I use Deoxit Gold. Just type "Deoxit" into Amazon to see what's available.

--Steve



On 10/12/2021 11:13 PM, CuriousMarc wrote:
I collect HP test equipment too… I use DeoxIt to clean such rotary switches. Good luck in your restoration!
Marc
-- 
Steve Leibson

Phone (Cell): 408-910-5992
Phone (Home): 408-292-4930


Please feel free to link to me on LinkedIn


History site: www.hp9825.com



Re: Cleaning Switch contacts and machanisms on HP239a Oscillator

 

I collect HP test equipment too… I use DeoxIt to clean such rotary switches. Good luck in your restoration!
Marc


Re: DREM Drive Emulator on HP9133H

Ansgar
 

Guess the problem is twofold. First, the processor or microcontroller needs to handle certain DIO lines fast enough which requires a certain processor speed. Second, the program flow has to be deterministic with respect to timing. You may achieve deterministic timing with alomst any processor or controller as long as interrupts and time sharing/multitasking are deactivated (e.g. via interrupt masking). But of course the processor or controller still needs to keep up with the speed requirements of the bus. Linux GPIB as the name says has been designed to run under an operating system with non deterministic timings. Same applies to MS Windows. So any deterministic tasks have to be done by a dedicated controller, the GPIB controller.

Using a bitbang driver shifts the deterministic tasks back to the main processor, which has diffculties achieving that deterministic behavior in a multitasking operating system. Which can be difficult, but is not completely impossible. IIRC, the floppy drivers built into Windows 9x stopped any other system activity during some floppy operations (which however could lock up the system under certain conditions). I guess it is much easier to bitbang DIO lines with a microcontroller with the proper timing without multitasking OS. Just like the firmware in the vintage devices.

-Ansgar


Re: Cleaning Switch contacts and machanisms on HP239a Oscillator

 

On 10/12/21 5:55 AM, Richard Merifield wrote:
I picked up a well loved HP239a oscillator in need of some care and cleaning. Still produces a super clean sine wave. Missing knobs etc makes the restoratin a chllenge.
The rotary switch contacts look rather fragile and I was wondering whether anyone had any experience on the best way to clean these and which product to use ? I have attached a photo, there is some oxidation visible. I am reluctant to pull the whole thing apart which makes access dificult.
Others have pointed you to the hp-agilent-keysight-equipment mailing list; I saw your subscription go through.

What you want for this is DeOxit D5. Apply it sparingly to the contacts and work the switches back and forth. Repeat this a couple of times. The carrier will evaporate leaving a protective layer behind; leave that there.

Good luck.

-Dave

--
Dave McGuire, AK4HZ
New Kensington, PA


Re: Cleaning Switch contacts and machanisms on HP239a Oscillator

Richard Merifield
 

Thanks Paul. Had not seen that group. I will join and post over there.

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