Have to repair a LIF 720Kbyte Diskette drive - Page 1
Forum section: electronics / repair

author: xantia_99
author_rank: Contributor
timestamp: June 19, 2021, 01:25:13 pm
content: HiI have to repair/exchange a SONY LIF diskette drive MP-F52W-30 for a HP 16500A. As I know it's problem to get everything to work with 16500A and these LIF diskette drive. However the other one is working and so does the analyzer. A transistor Q108 have gone on the PCB and probably more. But it seeks and rotate and can not find the system sector. The other drive work on the same cable. I can not find anything on Ebay or anywhere else just now.So a working drive or a PCB would be perfect. I also look for the schematic. I have find a good manual with the PCB view but no spare parts och schematic. Many words have been said about HP 16500A I know them all..Best RegardsStephan

author: dc101
author_rank: Regular Contributor
timestamp: June 20, 2021, 12:10:19 am
content: You might try looking into a floppy emulatorhttp://hxc2001.free.fr/floppy_drive_emulator/#SALESPOINTSIt seems this is a fairly common use case for them.

author: xantia_99
author_rank: Contributor
timestamp: June 20, 2021, 11:46:45 am
content: Hi,I will look into to that opportunity, thank you.Have to consider the LIF consequences in this case, if file names, LIF is not easy File system, or very simple compare with FAT, and so on is a problem. HP 16500a in not on comply official list, but test have been done with by users as I know until now.I consider to convert to B version or measure the the transistor from the correct drive in the curve tracer. With that find a transistor good enough. I might do that in any case, time will solve it.It's still an old system with problem with drive and strange behavior of cable location. That problem totally disappear for me if you keep the drives outside the box, CSR problem disappear. I spent a lot of time with that.I bought this unit for my memory of state analyse in the 80th with 8085 and it end up with totally spending my time on "possibilities" . I will not go to in every detail high voltage cable to close to the cover that made the unit reboot every time I put my hand on the top cover. But just push the cable more into center of the box it that problem disappeared. And so on..

author: xantia_99
author_rank: Contributor
timestamp: June 23, 2021, 12:42:36 pm
content: HiHappy to say I have solved the problem, two double common anod diode SOT-23 package on the PCB have replaced with 1n4148 discrete and now I boot the system from that drive.Happy and with saved money and time. Have to go from temporary solution to a more clean solution to make it possible to put the drive in position.RegardsStephan

author: amyk
author_rank: Super Contributor
timestamp: June 24, 2021, 12:36:24 am
content: Quote from: xantia_99 on June 20, 2021, 11:46:45 amFloppy emulators don't care about the filesystem. They just present a disk image to the host as a series of sectors.

author: xantia_99
author_rank: Contributor
timestamp: June 24, 2021, 11:07:21 am
content: HiI might come back to emulator if I change to the B version and more traditional diskette drive behavior and with that different pin architecture .The length of ribbon cable should not exceed 0.5 meter from the spec from Sony diskette drive, but it's nearly 1 meter. That might explain CSR errors. Specially in one of drivers. The controller is about 1:1 to the nearest drive and 1:5 to the second drive. The controller in the middle 1:1 from the first drive.That why I guess they changed to the B version very fast. Shorter ribbon cable and earth between active parts.I just made a short thought how to get file in from dos format to LIF format and right file names on the emulator, to get it so work with the controller. With lifutil.exe. Connect the emulator to a PC maybe. Just now I can not see that just now. The only way as I can see it is to copy files with the emulator in place on the cable through the controller and software with the CPU from the second drive. It would work. But that needs a very special cable I do not spend time on before B version. Just now I do not spend time on that. I also have a lot of traditional diskette drives for B version, I believe use standard drives, however this HP so ..My setup yesterday work very well and boot the system. After a nice implementation instead of a lab version it do not work that great again. Sometimes. But I have to change one more dual diode I realized late yesterday. So I will reduce cable and try to do a split up connector to scope and my second logic analyzer. My intention just now, maybe I just get new error from that. I will see. Keep the original cable away from that.Hope to not spend to much time on this, I want to come back on track soon.

author: xantia_99
author_rank: Contributor
timestamp: July 10, 2021, 02:18:41 pm
content: HiAfter a lot of measurement with scope and logic analyzer and interments problem I found out one of the wire of five in the flexible folio pcb is not working to the upper head. So reading is not possible from that head. It's logic with the analyzer response. I also compared it with the working drive.I have made many test setup with drive connected to new short cable and many other things with a HP 54622D MSO .It's simple to resolve this problem with a working head. I could use this analyzer with one drive.If someone do have this parts I would be happy to hear about that. Or otherwise I will change for B version and new problem or a emulated LIF drive other problem.Best RegardsStephan