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IBM AT

Gary C

Gary C

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May 26, 2018
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Lancashire, UK
Yes, I do have about 5 projects on the go at the same time but thought I would blog this one too.

We need an AT on display to show the development of the PC, but our only available AT was suffering from Epic rust.

Water had leaked onto the right rear of the case and the PSU case didn't survive

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Shouldn't work, but it does

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Its a little low, but the fact it works at all is surprising.

The main case has suffered a lot of surface rust, but a really good sand down and spraying with PlastiKote Stone has restored the textured surface really well.


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Its a little 'over textured' but once a few coats are on it should settle down but it feels really good now.

PSU, luckily found a very cheap replacement delta that probably doesn't work but I really only need the case.
 

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Excellent work. Shame the top cover of the pau is rotted out. I have saved metal that far gone... But once there is metal rot and chunks are missing.. well without a welder there isnt much you can do. Thenagain you could fiberglass it and use plastic filler to hide the pitting and work...
 
I did actually tinbash a new top but then having a good look at the lower part of the case, it was paper thin in places and all the screw holes were gone so I needed to do that as well. Then I found an identical unit for £20 with free delivery.
 
Absolutely amazing that the PSU still worked .. to have that much rust it has been leaked on for a long time. I'm also impressed how you did the casing .. what colour do you use for the top coat?
 
Its Rover Aurum white but its whiter that the original which probably should be the same gray/green Pantone 413 as an XT
 
I have to ask. I only own two 5170 AT's and one came with a severely leaky battery pack. Was that an issue on this one?
 
New PSU turned up and worked perfectly and the fan bearings are as silent as new.

Fitted with motherboard and MDA video card and no display. Video on port so monitor dead. Bad connection on slave power transistor socket, reseated and the lovely green etched screen monitor has leapt into life. The motherboard works perfectly. Its the 6mhz early board with 512k of piggybacked ram and it all seems to work great.

Not so with the disk drives. The card has suffered from some corrosion and appears to be dead, and the MFM drive is making the most awful noise. Might be worth investigating XTIDE for this machine, but its amazing the motherboard works perfectly :)
 
Good stuff. XTIDE cards are definitely worth getting. You can use any old piece of shit spinning rust hdd then. Like the Bigfoot 2gig drive in my Redstone Computers XT Turbo syste. The Bingfoot fills up a 5.25" drive bay without any adapters ;)
 
As I understand it, I can get an XTIDE card and that would have the boot rom and an IDE connector but would need a floppy card, or fit the rom to a network card and fit an ISA IDE/Floppy card ?
 
Just get a XTIDE card and a standard multi i/o card with floppy and IDE connections as well as seria, parallel and if you are lucky has a games port.
You can reasine the IDE channels to the second and third IDE channels(conpleytely disable them if you want) with jumpers as well add 5.25 and 3.5" fdds.
 
Gary C said:
As I understand it, I can get an XTIDE card and that would have the boot rom and an IDE connector
Click to expand...
So you have the early Type 1 5170 board with the piggybacked ram, What revision of the IBM BIOS does it have ?, If the IBM BIOS is the stock 01/10/84 for the Type 1 board, You will need to upgrade to the later 06/10/85 OR 11/15/85 IBM BIOS, But why fit an 8-bit XTIDE card in an AT, It's going to be slow.
Gary C said:
but would need a floppy card,
Click to expand...
Yes, IF your original IBM MFM / Floppy combo was working you could have tried that in an 8-bit slot just to run the floppy drives.
Gary C said:
or fit the rom to a network card and fit an ISA IDE/Floppy card ?
Click to expand...
Using a 16-bit IDE / Floppy Controller would be the better option in an AT, If you have a spare 16-bit ISA / IDE floppy card with it's own BOOT ROM socket you could use that to home the XUB, OR you can use a BOOT ROM socket on a NIC card OR you can use ROM Sockets U17 and U37 on the Motherboard if empty.

Depending on how much drive space you require, another option is to add a 1024/16/63 drive type in the IBM BIOS or modify a pre-existing one, You will be limited to around 504Mb ish, And you will not require the XUB.

I must add there are pitfalls doing any of this with the Type 1 Motherboard, If you haven't already have a good read of the 5170 and XT-IDE section on minuszerodegrees.net
 
I think your right about using a 16bit multi I/O card. I suppose the attraction of the XTIDE is the software config ?
 
Gary C said:
I think your right about using a 16bit multi I/O card. I suppose the attraction of the XTIDE is the software config ?
Click to expand...
It's entirely your choice, The 8-bit XTIDE card can be flashed in situ using XTIDECFG.COM, But it is slower than using a 16-bit multi I/O card in an AT.

The difference is, Using a 16-bit multi I/O card will be faster but you will need to configure the XUB first and then burn your own Eproms using a programmer.

Edit: Another option is to use a ROM Board like the Lo-Tech ROM Board that uses the SST EEproms, The latest revision of XTIDECFG.COM now supports the SST EEproms used on the Lo-Tech boards, So you could use XTIDECFG.com to flash the EEPROM . It means you use up another slot and more expense though.
 
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The XTIDE cards are not that slow at all in 286s systems I've tested. Better than my original 286/16 clone systems 40meg hdd back cn the early '90s.

Around 20secs the the Dos prompt on both my XT Turbo systems from a cold boot. 45secs to boot directly to the Geoworks Pro 1.2 desktop on the XT Turbo with EGA monitor and 2gig BigFoot spinning rust drive....
 
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VERAULT said:
I have to ask. I only own two 5170 AT's and one came with a severely leaky battery pack. Was that an issue on this one?
Click to expand...
I've got an early revision 5170, piggybacked RAM as well. Battery bombed. I think it's repairable, will start a thread on it eventually. Have to desolder and replace a couple chips, get a new crystal, and I need to do any further troubleshooting that it would require. It was stored in a similar state as the AT in this thread, it's got a LOT of rust on it and needs repainting bad. May do it in some fun color as it will never look original again. PSU and the floppy drive work though, pretty sure the MFM/floppy controller is good too, although the hard drive it came with was dead as can be. Full-height 20MB Rodime.
 
Caluser2000 said:
The XTIDE cards are not that slow at all in 286s systems I've tested. Better than my original 286/16 clone systems 40meg hdd back cn the early '90s.

Around 20secs the the Dos prompt on both my XT Turbo systems from a cold boot.
Click to expand...
I mean in Reading and Writing, In my testing i did some time back using my 5170 with Type 3 mobo, My IBM 5162 and a lonesome Type 1 5170 board there was a fair difference between using an 8-bit XTIDE card and a 16-bit IDE / Floppy controller, Also depending on drive type used of course.
 
The cover is supposed to be a darker gray color, but anything is better than that rust!

ATs originally came with a decorative plastic panel to cover up the back, but most went missing decades ago.
 
3lectr1c said:
I've got an early revision 5170, piggybacked RAM as well. Battery bombed. I think it's repairable, will start a thread on it eventually. Have to desolder and replace a couple chips, get a new crystal, and I need to do any further troubleshooting that it would require. It was stored in a similar state as the AT in this thread, it's got a LOT of rust on it and needs repainting bad. May do it in some fun color as it will never look original again. PSU and the floppy drive work though, pretty sure the MFM/floppy controller is good too, although the hard drive it came with was dead as can be. Full-height 20MB Rodime.
Click to expand...
I really need to get back to mine. Everything on it was shorted when I bought it. I havent repaired the PSU yet, had to borrow one from another machine. The board had a bunch of shorted tantalums. The video card has shorted tantalums. The floppy/hdd card had shorted tantalums.. I replaced them and the system now boots but I cant get a hdd working in it. The 5151 had some issues but thats working now. The mda card I still cant get working, it causes a short. If I can bypass tge hdd cad and use an XTIDE I will do that but with the AT setup program I dont know if thats possible.

vwestlife said:
The cover is supposed to be a darker gray color, but anything is better than that rust!

ATs originally came with a decorative plastic panel to cover up the back, but most went missing decades ago.
Click to expand...
Its true, Only my newest AT came with the rear cover. Held on with a bunch of pieces of Velcro (factory by the looks of it). If this didn't come with one I wouldn't have known that it was supposed to.
 
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