VOGONS


Tex's IBM XT 5160

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First post, by carlostex

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I managed to get an IBM 5160 locally in Portugal. I never thought i would find one in Portugal let alone while being on vacation. But it seems every cloud has it dilver lining and i stumbled on one.

First things first the monitor. I made no pic of it but it's a IBM 5151. The monitor does not seem to be in good health so i didn't even tried to power it on.

Now for the main unit and the hardware inside:

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Hercules card, was really happy to see that since i was expecting crappy MDA:

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This one seems to be a RAM card?:

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A Western Digital MFM/RLL HD controller:

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Of course it comes with the basic floppy controller and it has got a Network card that will probably be useless to me.

Now the not so much great condition IBM Model F:

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It seems to be in great conditions doesn't it? Well it wasn't working so i had to open the bugger and:

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Ugh, duct tape in the cable and the damn thing wasn't grounding properly so it would hang my XT test bench. So i stuck the thing on the keyboard rest spring and sure enough the damn thing started working.

Now for the bad news. The space bar wasn't seated properly so thr silly man in me made the terrible mistake of pulling the space bar out. I didn't brake anything but YOU SHOULD NEVER PULL A SPACE BAR OFF AN IBM MODEL F KEYBOARD. The space bar rests on a metal stabiliser that is impossible to reseat again without disassembling the metal plates. WTF IBM? Stupid over engineering much?

Well i need to clean it so tomorrow being extremely careful i'll reseat the damn thing. But i know it's gonna be a pain. Needless to say i didn't even boot the machine nor i'll boot it tomorrow since the keyboard will take my whole time.

One thing for the IBM Model F. The typing experience is great and apparently its springs are softer when compared to an IBM model M. It feels great for typing and it should be fine for some XT gaming.

More news to come-

Reply 2 of 40, by raymangold

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carlostex wrote:

Now for the bad news. The space bar wasn't seated properly so thr silly man in me made the terrible mistake of pulling the space bar out. I didn't brake anything but YOU SHOULD NEVER PULL A SPACE BAR OFF AN IBM MODEL F KEYBOARD. The space bar rests on a metal stabiliser that is impossible to reseat again without disassembling the metal plates. WTF IBM? Stupid over engineering much?

One thing for the IBM Model F. The typing experience is great and apparently its springs are softer when compared to an IBM model M. It feels great for typing and it should be fine for some XT gaming.

More news to come-

Nope, only the Model F AT, F XT and 'blueswitch' have the early internally mounted spacebar. Other Model Fs such as the 122, 104 'unsaver', 4704 series and others have the spacebar mounted like a Model M.

http://deskthority.net/wiki/IBM_Model_F

Reply 4 of 40, by Anonymous Coward

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It's interesting that none of the cards inside are IBM. I wonder if they failed, or the original buyer bought it barebones. BTW, I think the memory expansion card adds an extra 256kb to the system. If you want to upgrade to 640k, there is a way to put it all on the motherboard without the need for expansion cards, but you have to make one small modification.

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V'Ger XT|Upgraded AT|Ultimate 386|Super VL/EISA 486|SMP VL/EISA Pentium

Reply 6 of 40, by carlostex

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Update!

I've been focusing on one thing at the time. So my priority was to fix and clean the wonderful piece of hardware, the IBM Model F keyboard.

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Keys out, got them all soaked with warm water and Fairy dish cleaner:

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Disassembling the IBM model F can be a bit tricky. So i followed the advice in this page. It gives great advice an insight about the process and all the steps necessary to do this correctly.

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Now on the next pic i had already cleaned the main metal plate which was incredibly dirty and dusty. Fortunately no rust spots on the plate. At this point i already had the Space Bar mounted, there's no other way to lock the stabiliser bar on the spcae bar when the back plate + pcb joins the front plate + key hammers.

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Using a hair dryer to get those keys all nice and dry:

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All keys in again!

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Now, at first some of the keys weren't registring. Because the reassembly process is a bit tricky sometimes the hammers need a little kick to go back into place and be properly placed against the PCB. I had 5 or 6 keys that weren't working properly. It's a good idea to actually remove those keys. Pressing on the spring did register the key presses so it was just the matter of puting the keys back in and now the keys would work. So i went to CheckIt to try keyboard tests. Checkit is a very useful diagnostic software btw, really cool.

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This was all tested in my Juko Turbo XT motherboard. My next step is actually to disassemble the main unit and get everything all nice and clean. I'm a little suspicious about the power supply that came with it. It seems that sometime during the machine's life the PSU was replaced since now it has a 63W PSU. I'm sure that for an IBM 5150 the 63W PSU could make it but for an XT with a hard drive?

The hard drive in it is a Rodime HD! I didn't take a proper picture nor did i take notice of the model, but it could be its a R0352 model, which was one of the first 10MB 3.5" Hard Drives.

raymangold wrote:

Nope, only the Model F AT, F XT and 'blueswitch' have the early internally mounted spacebar. Other Model Fs such as the 122, 104 'unsaver', 4704 series and others have the spacebar mounted like a Model M.

http://deskthority.net/wiki/IBM_Model_F

And how relevant are those models for an XT? As far as i know those aren't compatible with an IBM PC or compatible.

bjt wrote:

Excellent! Lots of fun ahead!

Indeed, working on the model F was already a gratifying experience!

keropi wrote:

nice find! what upgrades come next? 😁

I think this machine will indeed need some modding. I don't trust the PSU so much so probably i will try using an AT or ATX PSU and somehow recycle the rocker switch on the XT PSU so there is no cosmetic change and fucntionality. An IBM XT without a rocker switch is not IBM XT anymore.

Obvious plan is an original IBM CGA. There's just no way around it. Finding a true CGA monitor is very hard. The only option for me locally in Portugal is to find a Commodore 1084S with a 9 pin digital RGB input.
But the easiest solution is CGA to SCART. I do have a small CRT TV's stashed so i would like to use that. Those TV's are relatively easy to find in Portugal too and i should find one that accepts composite as well. Not to worried about that. In the mean time i can always use a VGA card on the 5160.

Anonymous Coward wrote:

It's interesting that none of the cards inside are IBM. I wonder if they failed, or the original buyer bought it barebones. BTW, I think the memory expansion card adds an extra 256kb to the system. If you want to upgrade to 640k, there is a way to put it all on the motherboard without the need for expansion cards, but you have to make one small modification.

I didn't take the Floppy controller card out to picture it but i think it is the original IBM floppy controller. Will check later.

Scali wrote:

Needs more CGA! 😀

Indeed, and the plan is to have it! 😀

Reply 7 of 40, by Scali

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By the way, this is the first time I see a real Hercules card in such a machine. I've seen and owned various XT clones and clone CGA/Hercules cards, but nice to see the real thing.
If you don't plan on using it anymore, I'd like to have it.

http://scalibq.wordpress.com/just-keeping-it- … ro-programming/

Reply 8 of 40, by carlostex

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Scali wrote:

By the way, this is the first time I see a real Hercules card in such a machine. I've seen and owned various XT clones and clone CGA/Hercules cards, but nice to see the real thing.
If you don't plan on using it anymore, I'd like to have it.

I'll keep that in mind. I always wanted to try and use an Hercules card in conjunction with a amber monitor. I always like the look of monochrome with amber color. If i decide not using it i'll let you know or perhaps we can arrange a trade for something i might be looking for.

Reply 9 of 40, by Scali

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carlostex wrote:

I'll keep that in mind. I always wanted to try and use an Hercules card in conjunction with a amber monitor. I always like the look of monochrome with amber color. If i decide not using it i'll let you know or perhaps we can arrange a trade for something i might be looking for.

I have an amber, a green and two paperwhite monochrome screens 😀

http://scalibq.wordpress.com/just-keeping-it- … ro-programming/

Reply 12 of 40, by keropi

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The main problem with EU 1084s is that they don't support NTSC over composite... TTL will work fine (I have a 1084S-P1 now and it's great for ttl/cga) but you might as well forget the composite output with a PAL 1084. Even with a gaming composite ntsc->pal60 converter you won't get a good picture - it will be horrible and with almost no color.

I *guess* one can replace the onboard PAL TDA4570 with the NTSC TDA4510 encoder but you would also have to change the peripheral resistor/caps/xtal/ic's , add the TINT potentiometer and pray that the crt panel will work with NTSC. The holes/traces are on the pcb (they made them universal and populate accordingly) but the whole modification really demands specialized knowledge and GOOD quality schematics of the monitors , not the low-quality cr*p that you can download...
It would be nice to have the option to convert but I doubt someone with the knowledge will be motivated enough to show the way 🤣

🎵 🎧 PCMIDI MPU , OrpheusII , Action Rewind , Megacard and 🎶GoldLib soundcard website

Reply 13 of 40, by bjt

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Great work fixing the Model F. I wasn't brave enough to disassemble mine, just pulled the caps and cleaned the top plate as best as I could.

A 1084S would actually be a great option for TTL. The picture will likely be sharper than an IBM 5153.
Or, you could keep the mono card and run a CGA alongside just for composite games. I believe a small LCD TV will do NTSC no problem.
A late model CRT TV might do it too, even in EU.

Reply 14 of 40, by keropi

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a late model crt is nice and fine, it just looks crap on top of a XT 🤣

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the 1084 in TTL looks better than cga->scart on the above trinitron set... using an lcd for composite will work but will look crappy 😵

🎵 🎧 PCMIDI MPU , OrpheusII , Action Rewind , Megacard and 🎶GoldLib soundcard website

Reply 15 of 40, by carlostex

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Great advice, thanks everyone!

I think CGA to SCART is still the best option. I was surprised with bjt's results on his XT laptop thread, so it's cheap and i have a very good small sized Toshiba LCD which i can force to 4:3 aspect ratio and i think it will handle composite NTSC. So all i need is to get an IBM CGA card and deal with the PSU.

Reply 16 of 40, by Scali

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carlostex wrote:

How many CGA screens do you have then? How about EGA? EGA screens are much harder to find than CGA even.

I have one working CGA screen (1084S), and one that could probably be repaired (CM8833).
Don't have any EGA ones, but I don't have an EGA card either.

http://scalibq.wordpress.com/just-keeping-it- … ro-programming/

Reply 17 of 40, by bjt

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carlostex wrote:

I think CGA to SCART is still the best option.

Check this out, apparently works well with CGA and implements the brown fix.
http://bit-c128.com/

There's also this circuit using 74 series logic for the brown fix.
http://www.insentricity.com/filedb/7/1/7417.png

Reply 18 of 40, by keropi

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built and tested , no need to look further - need to also build the separate h+v sync combiner to get all the needed signals

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Reply 19 of 40, by carlostex

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Cool, i'll have to hover around on of you guys to build one for me. 🤣

No doubt it's the most economical and versatile solution. I just need to get an IBM CGA.

MobyGamer wrote:

Never, EVER pull the space bar off a Model F! (or M for the matter) Cringed when I read that.

Learned the hard way, but i had cold enough blood to place it back while also cleaning and restoring its good looks.