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IBM ps2 P70 portable repair thread

VERAULT

VERAULT

Veteran Member
Joined
Jan 30, 2012
Messages
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Location
Connecticut, USA
So I have begun work on my iBM p70 portable now that my MCA hdd card came in. I wrote a reference diskette but it couldnt boot. Guess its been 5 years since I last tried it.. without a hard drive not much I could do. I read about the caps being bad and leaky on the floppy drive... and thats exactly what they are so im about to do a recap. Next question is the battery. It doesnt have one.. Can I use two CR2032 in series for the 6.2V? Or does the p70 use a rechargeable battery pack? How should I handle this?

IMG_20240303_170401.png
I am counting Four 4.7uf SMD caps and one 10uf smd cap and whatever is going on with that thing I circled? Is that a solder blob joining a couple pads?


EDIT. Crap! Three of these are non polarized!! I dont know if I have them....... Ill have to put in an order and just replace the two in this photo for now... I hate BP caps!!!!
 
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HAH! The drive is working now with just those two caps replaced! I still have the other caps on order and will replace them when they come in.

The disk I wrote from the p70 reference disk booted. I will try to add the ADF File for the CF hdd card.
 
Well seems those last 3 bipolar SMD caps I didnt change gave up the ghost. Without a battery to save the settings I couldnt get to far. Now the system just boots to BASIC bios.. Im assuming the floppy is the culprit. So I ask again. What should I do about this battery situation?
 
I spoke to soon. The floppy cable is so small and tight it was pulled out a hair.

I made progress today. I was able to follow the instructions with my new CF HDD adapter: https://zzxio.com/product/mcide-cf/
following the instructions: http://zzxio.com/wp-content/uploads/2023/08/McIDE-CF-User-Manual-v1.2-h1.0.pdf
I modified the IBM reference disk and set the card up. I used the d400 memory range for the XTIDE bios and it seems to be ok.
I pulled the cf cards already loaded from one of my 486 projects im currently working on.

Here are some screen shots of Checkit3
IMG_20240304_121324.jpg
IMG_20240304_123227.jpg
IMG_20240304_121418.jpg
Not sure why it says 307mhz 486 though. Also It has a 387 match copro but its saying 80486 fpu instead..

IMG_20240304_121506.jpg
As I said the XTIDE is resident in the D400 range but even though the PDF states this is a 16KB option rom its only showing 8kb?!

IMG_20240304_121621.jpg
There is some ghosting. Is this something that can be addressed or do I have to live with it?

IMG_20240304_121559.jpg

Seems im not getting all the colors/shades as evident by the windows logo. IS there a specific driver for the p70? Im just really not familiar with this model. If anyone knows it well please share the info.

IMG_20240304_121631.jpg
Overall it looks pretty good. I have no lines or bad pixels in the gas plasma display (my compaq portable III was also a perfect screen when I sold it to another member) I have been lucky with plasma screens.

I need to address this battery RTC situation. I really dont want to add a PS2 camera style backup battery for fear of leaking. I took out the MCA modem as I have no need for it so after the CF card I have one slot free. How much do the MCA sound cards go for these days? Its its super expensive ill go the parallel port route.

As I decided a few years back I WILL NOT be collecting IBM PS2 computers as I really kind of despise them. This is the only exception as I just love luggables.
 
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Can someone tell me if this unit supports Bi-directiona LPT as I cannot get my SD2LPT device to work on it. IS there something I have to set like a jumper? I cannot find anything in the system reference disk.
 
VERAULT said:
This is the only exception as I just love luggables
Click to expand...
I really like my P70 but haven’t had much time to mess with it. I had 4 (?) bad caps in the floppy so gave up on that and used a gotek. Not sure about the LPT. I had some dumb MCA scanner card in mine so tossed that. Was hoping to get an Etherlink III card some day. MCA sound is gonna be quite expensive from what I recall ($300?)
 
agentb said:
I really like my P70 but haven’t had much time to mess with it. I had 4 (?) bad caps in the floppy so gave up on that and used a gotek. Not sure about the LPT. I had some dumb MCA scanner card in mine so tossed that. Was hoping to get an Etherlink III card some day. MCA sound is gonna be quite expensive from what I recall ($300?)
Click to expand...
Was the corrosion to bad to replace them? I think there are 5 caps in total. I did two and my drive started working I have the other bipolar caps on order as a preventative measure. Do you still have the broken drive?

Back when I had a few ps2 systems i bought a scsi card. But it had no bios and I searched for a couple years and couldnt find a bootable bios rom so I traded that card away. Networking would be nice but its not the end of the world now that I have a CF card hdd setup.

Actually I knew they were making new mca sound cards so there are options. One of course is the parallel port option which I have tried out on my toshiba 486 laptop (serdashop.com). Those work well and with shipping to US would be about $70.00 for the device.

But I think I am going to go with the adlib card clone for the mca bus by texelec for a few dollars less, check it out: https://texelec.com/product/resound...ble-card-for-ibm-ps-2-microchannel-computers/

Im going to play with an internal speaker setup as well.
 
Well the 6v cr2032 battery setup I bought did the trick. https://www.ebay.com/itm/254628295576

I set the system config. Pulled the power for 40 minutes and booted it back up. It retained the date/Time and settings

The bipolar electrolytic caps came in as well so I will finish the floppy drive tomorrow and get the PC back together.
 
I replaced the final 3 bipolar capacitors on the floppy drive this morning and retested. It works great. I started cleaning the computer. I never have before. Its not horribly dirty but there is old grime all over it especially the keyboard. I gave it a decent surface cleaning.

Its missing one of the rubber bumpers on the monitor left side for when you close the keyboard. Ill have to find some small flat rubber foot to fill that hole.

The keyboard cable has some cracks but only in one place nearest the monitor.
IMG_20240307_100747.jpg

I found a crack on one of the clips on the back cover. I used a heatgun to try and set it back into place and a drop of super glue to set it.

IMG_20240307_102313.jpg

Its now back together and the first thing I noticed when trying to run things is how SLOOOOOOOOW it is. I dont know what this cyrix 486 is doing but it barely feels like a 486. It must be an extremely slow or early 386 bus on this board.

IMG_20240307_124221.jpg

Its maxed out at 8mb of RAM. Apparently with a special 486 upgrade card you can get up to 16mb. But I am guessing those cards are as absurdly priced as Macintosh cpu upgrade cards and every IBM PS/2 collector is out for them so I am going to live with 8MB: https://jshorney.incolor.com/p70.htm#p70up

And now for some gratutitous glamour shots of the system together with some random screen shots (I absolutely hate how the computer interprets anything orange/red to BLACK) youll see in images below
IMG_20240307_123919.jpgIMG_20240307_124004.jpgIMG_20240307_124035.jpgIMG_20240307_124353.jpgIMG_20240307_124508.jpgIMG_20240307_124819.jpgIMG_20240307_125134.jpg
 
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One thing I found out was that square connector on the back Io is a SCSI HDi30 connector. But Does this computer have a built in scsi connector? Could I have used a scsi2sd device this entire time? I really couldnt find too much information on this so Its still a mystery to me.

Also a mystery is the parallel port. I have no idea how to set it to bidirectional so I can use my SDLPT device and my backpack cdrom.

Im glad this thing finally does SOMETHING rather than exist on my shelf. At some point I will get the aforementioned adlib sound card but im in no rush for that. The machine is now up and running.
 
VERAULT said:
One thing I found out was that square connector on the back Io is a SCSI HDi30 connector. But Does this computer have a built in scsi connector? Could I have used a scsi2sd device this entire time? I really couldnt find too much information on this so Its still a mystery to me.
Click to expand...
No, the 'Hosiden' connector is for an external 4869 5-1/4" diskette drive: https://www.ardent-tool.com/8573/Common.html#ESD_Port
 
VERAULT said:
So I have begun work on my iBM p70 portable now that my MCA hdd card came in.
Click to expand...

I have two heavily modified P70s, but it doesn't take much to fill up the original HDDs.

Is this the one you used?
zzxio.com

McIDE-CF - ZZXIO

Parallel Advanced Technology Attachment Micro Channel Architecture Bus Interface Adapter
zzxio.com zzxio.com

If so, can you also keep the original C: and use the CF as D:?
 
Torch said:
I have two heavily modified P70s, but it doesn't take much to fill up the original HDDs.

Is this the one you used?
zzxio.com

McIDE-CF - ZZXIO

Parallel Advanced Technology Attachment Micro Channel Architecture Bus Interface Adapter
zzxio.com zzxio.com

If so, can you also keep the original C: and use the CF as D:?
Click to expand...
Yes thats the card i have! As far as using the original hard drive i couldnt tell you as mine is dead .
 
Cool, I didn't realize someone finally came out with an MCA version. Reasonable price too.

I'd also like to get the tex-elec Resound board as it appears to have joystick support. I wish there was a modified riser or some other way to squeeze another slot in these things. I have a Kingston MCMaster installed, so I'd have to choose one or the other.
 
Torch said:
Cool, I didn't realize someone finally came out with an MCA version. Reasonable price too.

I'd also like to get the tex-elec Resound board as it appears to have joystick support. I wish there was a modified riser or some other way to squeeze another slot in these things. I have a Kingston MCMaster installed, so I'd have to choose one or the other.
Click to expand...
Can you share some photos of the mcmaster?

Same with me.. had no idea this thing even existed.

The resound is just a bit too much to spend for me.. but i just bought the resound 2:
texelec.com

Resound 2 OPL3 MCA Adlib Compatible Card for IBM PS/2 Microchannel Computers - TexElec

Welcome to the Resound 2 OPL3 MCA Sound card! With the release of the IBM PS/2 line of computers back in 1987, IBM also released a new expansion bus known as MCA or microchannel architecture. This was a 16 or 32 bit bus with some early “plug-n-play” style features. This includes installing and...
texelec.com texelec.com

Cant wait till it comes in .
 
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