IBM P90 730 Model 6875 HELP PLS!

oh yes yes ok you are way cooler than all of us working with motorbikes instead of old computers thx so much for boosting all our confidences :wink: haha!

J/K :smiley:

Here’s an IBM Model 5150 so I can keep my “street cred”.

Beautiful! It’s your dad’s! ;D lol only joking mate honestly :hugs:

Have to say though I’m not too fond of those monitors they look too much like old tv’s to me.

They essentially are old TVs. :wink:

That’s a CGA monitor, which is actually a “digital” display, so they’re not exactly just a TV; however, the 5150 does have a composite video output which can be run to a standard TV. 80 column text is very hard to read on a TV, but graphics look fine.

To come to Ethan’s assistance, I’ve a bike license, too (however, it’s mostly still new in box) and for my “street cred”, here’s my Sharp MZ-80K (the brick below is a Olivetti M15 – according to the manual, the battery is up for replacement, when it only lasts for 6h).
And, these IBM monitors are about the coolest there is about the PC! :slight_smile:

BTW, there is no doubt how to open these, you just open the hinge (much like with the PET).

P.S.: Since this is a really poor photo and this is about opening computers, here are a few photos from the restoration process…



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Hya thanks for the pics! That Sharp is interesting I really loved Sharp back in the day they made some really nice mini hi-fi/audio gear. Nowadays they make some pretty decent microwaves! Do you use it for anything? Does it have any software? The keyboard is great to type on, I’ll bet.

I am going to use my IBM for word processing, since I am an aspiring writer. Modern PC’s just don’t inspire my creativity much (I have 3 manual typewriters that I use also!). I have bought Wordperfect 5.1 floppies as well ready to install this weekend I can’t wait! Oh yes… I need to get some blank 5.25 floppies to play with… They are really expensive now on Ebay.

Hi Ethan. Oh it’s a perfectly decent monitor, I know. Just the aesthetics I have an issue with. The monitor I have with my IBM is great… worth the money I paid for the computer alone. You can flick between normal, green screen, amber AND blue a la C64)! Great for writing. It is a kind of generic ICL brand, though.

The floppy drive I bought is a new never used Mitsubishi. Just look at those sleek lines and sharp looks. Much sexier than their dumb nerdy motorbikes! Haaahaaa! :wink:

Not so much as I would like. Partly, because there is no built-in software besides a tiny loader-monitor program. (The Sharp MZ series favored the “clean machine” paradigm, where you have to load any software, including BASIC.) The only way to get something on it is the built-in cassette drive (which is pretty fast, which comes with its own caveats, you can’t use MP3 files, because their fidelity is too low) and this is somewhat complicated nowadays, esp. when it comes to saving things. (There were also disk drives and even a punch card reader, but these require an aditional I/O box, which is pretty rare, see fast cassette drive.)

The keyboard is, well, interesting. It’s better than most chiclet keyboards of the time but feels like it could use a fair bit of oil. :slight_smile: Probably not a typist’s dream. (Also, for whatever reason, I tend to get confused with the cursor keys.)

Historically, it’s an interesting machine: Introduced in 1978, it was originally sold in semi-kit form in Japan, meaning, it came in preassembled units, which you had to put together on your own. (This really marks the transition from kit computers to ready-to-go consumer machines. Why it was delivered in parts, at all, is a bit of an enigma, maybe this helped with shipping. Maybe, this was still essential to its credibility as an affordable computer. In export markets, it was sold fully assembled and dealers usually maxed out the RAM to the full 48K. They were not sold where I live, so I got mine from the UK, where they were fairly popular.) But this didn’t hinder its success, even as a small business computer. Besides a few flavors of BASIC, it runs Fortran, Pascal and Forth. However, while a Z80 machine, it does not run CP/M without a few tricks. It’s more or less contemporary to the PET 2001, which was introduced in 1977, but wasn’t delivered in any quantity before the next year. While it does look somewhat similar, the PET is a much heavier machine.

(The monitor housing came in a few colors, dark brown, which is by far the most common, red, and even in yellow. The later MZ-80C featured a traditional keyboard layout and the successor MZ-80A had a normal keyboard and did away with the need for the IO-box for peripherals. The final iteration, MZ-80B, was a serious business computer and featured a pair of built-in micro drives and additional video planes for bit-map graphics.)

For a really great photo series, see Sharp MZ-80K (1978) | Oldcomputr.com

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It does look nice in those pics with the disks and all. Could have a lot of fun with that. The keys kinda look like those you would find on a cash register. I have just spent 2 days cleaning up a grubby Dell AT102W keyboard to use with my IBM (I am going to stick some white black labels over the Dell Logo as it is an IBM pc). I’m a bit OCD that way. Lol.

Here are a few more aspects of the keyboard. Apparently there are (kind of) switches, unlike with most similar looking ones. While there was a fair bit of dust accumulated between the keys, I didn’t dare to take it apart entirely, which is probably also the cause for this need-oil feel. However, it never was a great typing keyboard in the first place. (But then, most prospective users couldn’t type at all and it was somewhat unclear, what a home computer keyboard should look like. But one thing was quite clear already: it should be cheap to manufacture. Head tip to Sir Clive.)


Besides: a serious restoration tip
The computer came with a few scratches and even some rust on the front edge of the powder coated metal case. For the most, helpful people will direct you towards automotive lacquer, but it will be close to impossible to find the right color match. What I did, was treating the rusty spots with rust converter (after a thorrow cleaning and a bit of sanding) and paint it with enamel paint, like it’s used for modelling. (Still, you’ll probably won’t get a perfect color match on the first attempt, as these paints tend to darken slightly, when drying, and you may have to give it yet another try.) Moreover, these paints give great control. (E.g., there was a nasty scratch right through the logo, but I was able to fix this, as well.) No filler used, I just built up the paint. Now, 5 years later, the repairs are still perfect and indiscernible, even while on an exposed spot, where you’re prone to rub the case while typing.