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IBM AT 5170 start but do not boot with Dos

jackb77

New Member
Joined
Feb 4, 2017
Messages
7
Hello everyone!
I bought this IBM 5170 in very poor condition.

The configuration is:

Type 1 motherboard
First version of bios (2 eprom U27/U47)
286 6mhz CPU - No FPU
512kb ram
MDA adapter and 5151 monitor
First version of HDD/FDD Controller
Serial and Parallel card
Type 2 HDD ST-4026
Original 5.25 1.2 FDD



Picture here:
https://ibb.co/m9Wk4rf
https://ibb.co/wY9xBKv
https://ibb.co/gSRr6Lb
https://ibb.co/ss08VvD
https://ibb.co/C5DqCbg
https://ibb.co/x38SNc7

The main problem is a lot of corrosion maybe from the acid battery (however I do not find battery inside)

I took everything off, remove the rust from the case and clean the motherboard with water and soap and after with white winegar, and again water.

After I had to replace the keyboard AT connector (with some difficoult becouse was not easy to desolder it but a friend more expert with soldering jobs helped me)

I open the PSU clean it with compressed air and check the voltage 5v and 12v and that's are good.

This machine have a faulty HDD controller that prevents to start the computer.
Without this card the motherboard start and pass the ram test and give the error 601 and 161

My friend that have a later version of 5170, give to me his second version controller and I try to start
With this controller attached no more 601 error but now start the problem

I tryed the Floppy drive to another computer (a 486) and it works very good, I format some floppy and make ADV Diagnostic disk image and some DOS disk (PC-DOS 3.30 PC-DOS 2.0 and a 1.2mb 6.22 version)

I put the floppy drive back on the 5170 and when try to boot from it the system halt with only cursor on screen.
Without floppy disk inside or with a blank floppy it go to the BASIC page.

I try another generic IDE HDD/FDD controller with this drive and same result.

What can the problem? maybe some damaged components on the motherboard but how I check it???

Thanks to who can help me
 

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modem7

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Joined
May 29, 2006
Messages
7,896
Location
Melbourne, Australia
Hello everyone!
Hello.

I bought this IBM 5170 in very poor condition.
In case you are unaware, there is lots of IBM 5170 information at minuszerodegrees.net

This machine have a faulty HDD controller that prevents to start the computer.
See the "If this card stops your IBM 5170 from powering on ..." sentence at [here].

Without this card the motherboard start and pass the ram test and give the error 601 and 161
My friend that have a later version of 5170, give to me his second version controller and I try to start
With this controller attached no more 601 error but now start the problem
So you still have the 161 error, meaning that you need to perform SETUP.

I tried the Floppy drive to another computer (a 486) and it works very good, I format some floppy and make ADV Diagnostic disk image and some DOS disk (PC-DOS 3.30 PC-DOS 2.0 and a 1.2mb 6.22 version)

I put the floppy drive back on the 5170 and when try to boot from it the system halt with only cursor on screen.
Without floppy disk inside or with a blank floppy it go to the BASIC page.

Because SETUP has not been performed, the IBM 5170 will only boot from a 360K floppy (or a 720K diskette). Note that writing to a 360K floppy in a 1.2M drive is unreliable. For a guaranteed result, you need a 360K boot floppy that has been created in a 360K drive.

But you can perform SETUP via the motherboard's BASIC. See [here]. How about you do that. When the SETUP configuration knows that drive A: is a 1.2M drive, you should then be able to boot/read/write 1.2M floppies.

(For the IBM 5170, no battery is required to perform SETUP, although the SETUP configuration will be lost about 5 minutes after the motherboard is powered off.)
 

jackb77

New Member
Joined
Feb 4, 2017
Messages
7
I already know minuszerodregree, and thanks to this website I learned a lot of things.

I try a lot of floppy disk in 360kb format (advanced ibm setup, dos 2.0, dos 3.30 and even Dos Plus of Digital Research), everything freeze the pc with cursor on screen and red light of the drive stay on.

I try 3 times to perform setup via Basic, one time with HDD and the other without. I got always the 161 error, when I turn off and on the machine, and the last time I press ctrl alt canc instead of turn off. There is 6v battery (4x1,5v)
 

modem7

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Joined
May 29, 2006
Messages
7,896
Location
Melbourne, Australia
Multiple symptoms can sometimes have multiple causes.

For now, let us look at the 161 error ('bad battery'). The 161 was expected to disappear after you performed SETUP.

Refer to the diagram at [here].

With the motherboard powered off, pins 18 and 20 and 22 and 24 of the 5170's MC146818 chip (the 'CMOS/RTC' chip) are expected to be, for you, measuring about +5 volts (your 6V battery minus the approximate 1V drop of the two diodes).

With no battery attached, and the motherboard powered on, those pins will receive about +5 volts from the '+5V SWITCH'. As an example, I measured 4.7 volts on one of my 5170 motherboards.

Seeing that ?

temp_rtc7gj047nhg9526.png
 

GiGaBiTe

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Joined
Apr 30, 2015
Messages
2,747
Location
Austin, Texas
FB1 and FB2 are ferrite bead chokes/inductors. You can rebuild these by using the same gauge of bare wire and re-threading the bead. Getting the existing wire out without damaging the bead may be a challenge if it has rusted itself in place. Might try removing it from the board and soaking it in MC51 or Evaporust to convert the rust and loosen it up.

R17 is some sort of resistor, but with the bands being so damaged, hard to tell what it is. It looks like orange, black, brown, gold, which would be 300 ohms at a 5% tolerance. The size of the resistor looks like a 1/2 watt.

CR2 is a glass diode, which appears to be snapped in half from your close up picture. No idea what it is since the body is destroyed, but something like a 1n4148 might work to replace it.

Y3 is a destroyed crystal that looks to have had its outer shell eaten off. Judging by its proximity to the MC156818P (a real time clock chip), it's probably going to be 32.768 kHz Someone with a 5170 motherboard can confirm this.

But you have other problems, there are quite a few badly corroded VIAs all over the board and what appear to be damaged traces with the conformal coating eaten away. You'll need to do continuity checking on the VIAs to make sure they still connect to where they need to go, as well as traces. You'll ideally need to remove all of the ICs and clean under them, because corrosive substances tend to do the worst damage under chips. The chips can also hide damage that could be causing issues.
 

modem7

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Joined
May 29, 2006
Messages
7,896
Location
Melbourne, Australia
Please look these picture and if you know, can help me to identify these components?
In the vast majority of cases, you can work out component types/values from IBM's published circuit diagram of the IBM 5170 motherboard (of type 1).

1. Goto http://minuszerodegrees.net/manuals.htm#IBM
2. Click on link 'IBM 5170 - Technical Reference - 1502243 - MAR84'
3. Navigate to page 1-61 (which is PDF page 83)

The circuit diagram is on 22 sheets.
For example, R17 appears on sheet 22, showing as 300 ohms. (I confirmed that value by measurement of R17 on one of my type 1 motherboards.)
For example, Y3 and CR2 appear on sheet 18.

A second information source is the SAMS Computerfacts document that includes the IBM 5170 motherboard of type 1.

Note that neither source is 100% accurate; there are errors in places.
 

jackb77

New Member
Joined
Feb 4, 2017
Messages
7
After a lot of time, and an help from a friend that is good to soldering, the motherboard works!!!!!!!
We change some components and now I'm able to boot, but only with a 3,5" 720kb floppy. The 5,25" alway give me reading error, I clean the heads but it don't work

https://ibb.co/6ggwt5g

Now I'm able to run setup, I try the IBM Advanced Diagnostic Disc, but prefer GSETUP becouse this give me the option to set the 720kb as primary floppy.

https://ibb.co/ChDDZFB

Now, the next step is to put and Hard Disk, I got with this machine two MFM, a TYPE 2 and a TYPE 13, but no one seems to be working. they spin and make noise but not able to reading or format or low level format. :(
I open another thread to ask other argouments
 
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