On again, off again

[Stone]

Zut alors! C11 and C12 are three-legged and may be hard to find. Are you sure they can be removed?

The FDs are on rails. It looks as though there ought to be a tab on the front of the rail to secure the rail (and thus the drive) to the chassis. Have I got the wrong rails?

They're the biggest tants on the board! Anything can be removed. All you need is a soldering iron.

Yes, there are tabs for securing those rails.

 

[modem7]

The FDs are on rails. It looks as though there ought to be a tab on the front of the rail to secure the rail (and thus the drive) to the chassis. Have I got the wrong rails?

Yes, there are tabs for securing those rails.

At [here] are shown some homemade ones.

 

[Chuck(G)]

Don't worry about the 3-legged ones--I've posted several times on the subject--and where to find more.

Basically, they exist so that it's not possible to insert them in a PCB with reversed polarity (can you say "Bang!"?). A tant of the bipedal variety will work fine. I believe that MZD has a bit on this one also.

 

[modem7]

It is possible that I had the controller, which is a 16-bit card, in an 8-bit slot and caused the PSU to shut down in defense of its integrity.

I have not seen that with the IBM 5170.

( With the IBM 5170, with IBM BIOS, and the IBM supplied 16-bit controller, moving the controller into an 8-bit slot results in a '1780-Disk 0 Failure' error. )

 

[Stone]

Don't worry about the 3-legged ones... Basically, they exist so that it's not possible to insert them in a PCB with reversed polarity (can you say "Bang!"?). A tant of the bipedal variety will work fine.

Yes, provided you do not insert it incorrectly.

 

[pinkdonut666]

Yes, provided you do not insert it incorrectly.

Instructions unclear, got capacitor caught in ceiling fan...

 

[clh333]

Or I could just sell the thing on eBay as "NOS - untested."

-CH-

 

[clh333]

Okay, I was kidding about that. Everybody unclench.

-CH-

 

[clh333]

I found the AST software among the floppy collection. I think maybe I had an AST product in the original AT&T PC 6300 from the '80s and the disk is left over from that.

I also found a pair of tabs and some spare screws in a bag.

A new issue: DOS commands to select drive A: or B: are successful, but if I try to access the contents of a disk in either drive things get squirrelly:

On each drive I have received the message "On-board parity error - system halted" after issuing a "DIR" command. On drive B: the error was indicated at 0000:DAFA (56,058) two times in succession, after resetting, and on drive A: once at 0000:0A02 (2,562). I tried to repeat the error on Drive A:, which is a 1.2 5.25, but the second attempt read the directory with no error.

However, subsequent directory reads read only a partial list of the files, and when I TYPEd some of the text files I would get strange characters or gaps in places.

My first hypothesis was a motherboard memory issue; my second was a problem with the RAMPAGE board and my third was a problem with the floppy chain, maybe termination or lack thereof. I think I'll start with the drive chain: the HD seems to be performing properly. (MS-DOS 6.22 is on a 2 GB partition on the Bigfoot).

-CH-

 

[Stone]

On each drive I have received the message "On-board parity error - system halted" after issuing a "DIR" command. On drive B: the error was indicated at 0000:DAFA (56,05B two times in succession, after resetting, and on drive A: once at 0000:0A02 (2,562).

0000:DAFA looks like a ram error on the expansion board

0000:0A02 Looks like a video ram error

 

[clh333]

I tried several substitutions and BIOS configurations for floppy drives; with and without termination, as A:, as B: but kept getting errors until I removed the RAMPAGE card. Without the card in the system the floppy drives respond to commands, display directory information and copy from drive to drive as expected.

This proves nothing, but suggests a test of the RAMPAGE card itself is warranted. Is there an utility for that? Do I need to start building that Arduino RAM tester?

-CH-

 

[Stone]

Just check the ram chips.

 

[clh333]

Just check the ram chips.

There are four banks of 18 each; 72 total. I pulled the card for now, as well as the IBM IO card. There are only the display card and the SIIG multifuncion which drived the HD and two floppies, plus COM, LPT and game ports.

I have other RAM cards to investigate: Everex EX-125, which was the subject of discussion here in 2008. Not sure if anyone ever found the manual but there are bare-bones instruction on Stason. Couldn't find anything on MZD. I also have the SixPack Plus, but I don't know if there's a hardware limitation that prevents it from being used with a '286 or a 16-bit ISA bus.

I've buttoned up the 5170 and will put it aside for the moment while I test some other equipment. But I'm pleased with having made some progress and I thank everyone for their contributions.

I think that from an industrial design viewpoint those IBMs were among the handsomest PCs built. I know, po-TAY-to, po-TAH-to, but I'm just a sucker for those 5151 monitors.

-CH-

 

[clh333]

Don't worry about the 3-legged ones--I've posted several times on the subject--and where to find more.

Basically, they exist so that it's not possible to insert them in a PCB with reversed polarity (can you say "Bang!"?). A tant of the bipedal variety will work fine. I believe that MZD has a bit on this one also.

Thank you, Chuck; I followed your advice and the previous posts to repair the board. I had 10uf 16V Ks on hand and used the two-hole approach.

In theory, if necessary, you could use two two-legged tants back-to-back, i.e. -++-, with both ++ in the same hole, could you not? You would select values that were half the capacitance, same voltage rating as the three-leg you were replacing, I assume?

-CH-

 

[Stone]

In theory, if necessary, you could use two two-legged tants back-to-back, i.e. -++-, with both ++ in the same hole, could you not? You would select values that were half the capacitance, same voltage rating as the three-leg you were replacing, I assume?

Why would you put two caps in parallel when one two-legger is all that is necessary?

 

[Chuck(G)]

Dunno, but it would work.

 

[Agent Orange]

Also, remember that capacitors in series add like resistors in parallel and vice versa.

 

[MaCJaX]

Zut alors! C11 and C12 are three-legged and may be hard to find. Are you sure they can be removed?

I just replace one yesterday. They are the same as a standard 2 pin Tantalum cap. Just use a meter and see which pin is ground. That's your negative lead. If you use a meter and check continuity, you will notice the outer pins are the same. I believe when I did mine, the outer pins where negative and the middle pin was positive. Replace with same size and you're good to go.

 

[mcs_5]

Just use a meter and see which pin is ground. That's your negative lead.

Only for some of them!!! Ground is the positive lead, for the bypass caps on -5V and -12V...

 

[clh333]

You're way ahead of me, guys, but thanks for your advice.

-CH-