Our boards have a different layout. Look at my photos and you will see the 386 slot is to the left of the 387 socket. yours is up behind the top MCA board.First one is fitted with a 486 75mhz overdrive. The one with the fan is a 586 133mhz. Both have 64MB memory.
You also have a choice of going to the original 386 during boot, and then it's like the MCMaster isn't even there.
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I still have the broken drive. Yeah the corrosion was pretty bad, I recall the pads being gone on at least one of the caps. I might have pics, I’ll check.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?
Wow, I didn’t know there was an MCA CF card option, that’s awesome. I thought you were kinda screwed if you didn’t have one of those rare ESDI hard drives.Networking would be nice but it’s not the end of the world now that I have a CF card hdd setup.
This sounds like a great option, I may have to pick up one of these too. I like the idea of routing audio to the internal speaker.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/
Id like to see a pic of the drive caps if you get a chance.I still have the broken drive. Yeah the corrosion was pretty bad, I recall the pads being gone on at least one of the caps. I might have pics, I’ll check.
Im not seeing any pad issues. Are these old photos before you attempted repair. I do see trace damage from leaky caps but all the caps are still in place.
Why would you take off the pcb? They are SMD caps...How are people removing the spindle motor so that the PCB can be taken out? is the green material some form of loctite?
thanks.
ahh. I see now, solidpro's pix showed that the cap-style are SMD too, I thought they were through-hole.Why would you take off the pcb? They are SMD caps...
I wish you could have show some larger photos of the video board. Is it removable? Where is it in the system exactly? I have a sound card coming in so I can look into the machine again to address this. What are the values of this cap? is it polarized?Ok so word of warning to anyone with a P70. I originally only had a fault with my floppy drive, which was fixed by replacing the 5 capacitors with ceramic sm ones, lubricating the corkscrew thing and cleaning the head with IPA.
All 5 surface mounted caps on my floppy were leaking and crusty. I used non-polarised ceramic caps as a replacement.
This got it working:
Starting Point
Top 3 original non-polarised caps going bad:
See the fishy crust?
Cleaned:
Replaced with ceramics:
Bottom two polarised caps:
See the even-worse fishy crust?
Cleaned and reflowed:
And replaced:
I then went to check out the backup battery and order a new one and without even touching the video card, when I turned the machine back on, no video output and a long, low beep - indicating a video board problem.
I reseated the card to no change, so I removed it and the 4 capacitors on it were all leaking - with C1 in particular beginning to eat through all the tiny tracks that go around it:
See how rotten the through-holes were going, so close to lots of tiny tracks? I got to mine probably in the nick of time...
And replaced. Amazingly this brought my video back to life!
If you have a P70, take the back off, remove some of the expansion card stuff, remove the video card and replace these caps today - if they're left much longer, no more video!
One last thing, if the backup battery is dead and you get a 163/161, the first time you load the reference disk it takes aaaagges to boot - this isn't a fault with the drive or the disk, it just hangs at about 2 minutes instead of booting from floppy. Have a cup of tea and give it a few minutes.