Late 5150 + 5151 Restoration

[@stamasd8500]

Idea for fixing the pegs that hold the drive latch, at least temporarily: wrap each with 1 layer of PTFE tape (pipe thread tape used by plumbers). This should bulk up their diameter and allow for enough pressure inside the bearings so they don't come out so easily,. while remaining mobile enough to do their job.

[@Epictronics1]

I think that could work, thanks

[@Darxide23]

@@Epictronics1 I second this idea. PFTE tape is often called Teflon tape because that's what it's made of. It's durable and has a low friction surface so the latch should still move easily.

[@whochecksthis]

@@Darxide23Teflon is the trade name for the compound PTFE…

[@christopherdecorte1599]

I used a toothpick to fix that latch back in the day on my 486

[@Epictronics1]

I need to try that lol

[@alnoorratansi9364]

i think Adrian has a 3d printed part for this issue.

[@danielflakelar8193]

you were so lucky that the bottom of the display didnt crack and drop that psu. i have seen that happen. Always support that transformer. Its difficult but i now undo mine by having the display upright and undoing the screws from the bottom so the transformer can fall into the tube.

[@Epictronics1]

Yes, I noticed that it bent the plastic case more than I'm comfortable with. It's not a great design to place the PSU like that

[@bikkiikun]

If the glue / hotsnort is not a dried up (like here) you might want to use IPA. Let it get under the glue and work for a few minutes, then wiggle and sqirt some more and let it work, again. Bit by bit the glue will give way.

[@Epictronics1]

I'll try that next time. Thanks

[@BigBadBench]

Nice work! I think I remember seeing a 3d print for that part somewhere…

[@Epictronics1]

Thanks! I did a Google search but couldn't find it.

[@Nukle0n]

Fairly sure the BIOS on the original 5150 is spread across two chips, with each chip handling most and least significant bits. So I'm not sure about mixing different revisions.

[@Epictronics1]

I'll have to double check but I think the remaining ROMs are for IBM BASIC

[@Nukle0n]

@@Epictronics1 I might be thinking of the XT.

[@eDoc2020]

@@Nukle0n More likely the AT.

[@Nukle0n]

@@eDoc2020 I checked and the XT uses two chips for the BIOS, split across most and least significant bits.

[@eDoc2020]

@@Nukle0n That doesn't make sense because the ROMs are 8 bits and the bus is also 8 bits. Unless you're talking about the 5162. What motherboard version are you looking at?

[@ruben_balea]

I found a link to the "user manual" of that card on Vogons topic 917612, the most important thing is: *Jumper J1: 2&3 = 31.5kHz, Fully open = 18.432kHz. DO NOT bridge 1&2.* The manual is in Swedish, this is the Google translation: EIZO Monitor 4051 / EIZO Hercules card MD-B05 From Users Manual - Hitec Associates ltd 1987. - MD-B05 is a Hercules card that works with 31.5kHz line frequency. It is not standard so the MD-B05 is therefore only compatible with the 4051 monitor. However, the MD-B05 can be set to normal Hercules frequency (18.432kHz) to fit standard MDA/Hercules monitors. 4051 cannot be reset. - In addition to regular Hercules signals, the MD-B05 also has an analog 0.7V p-p output on pin 4. It can be used, for example, to connect the MD-B05 to one of the colors on an analog multisync screen. - 4051: Line frequency 31.5kHz Frame rate 63-70Hz Image size 244x184mm, 9.6x7.2" Line: (us) Image: (ms) A. 1.74 .--------. .-------. B. 3.50 | | | | -----' `----- -----' `----- C. 23.14 .-. .-. -. .-----------. .- D. ​​3.44 | | | | | | | | -' `------------' `- `-' `-' E. 0.51 |-|-|--------|-| |-|-|-------|-| F. 1.34 A B C D E F G H G. 11.14 H. 1.33 - MD-B05: Line frequency 31.5kHz / 18.432kHz Frame rate 70kHz / 50(60)Hz Dot.clock 31.11MHz / 24.00MHz Parallel Port Fixed as LPT1, 3BCh-3BEh Other 5V, 0.77A. Jumper J1: 2&3 = 31.5kHz, Fully open = 18.432kHz. DO NOT bridge 1&2. .------------------------------------------..- | 1== J1 .==. 25 pole dsub female | CN2 | || Printer port | `==' | .==. 9-pin dsub female | CN1 `==' To monitor | .--------nnnnnnnnnnnnnnn-'| `------------------' """"""""""""""" | 9-pin dsub: 1235=GND, 4=Analog, 6=+intensity, 7=+video, 8=+Hsync, 9=-Vsync CN3 is for the light pen. // Tomas Andersson 1994-07-20

[@Epictronics1]

It works! Thank you :) In the 18.432kHz mode, the image is about 30% smaller than with the IBM MDA card and the cursor is a small square. Looks a bit strange but it totally works :)

[@Epictronics1]

I posted a picture on Twitter

[@ruben_balea]

@@Epictronics1 For some reason KZbin didn't send me any notification today... At vgamuseum this card is listed as "Hitachi HD6445 CRTC-II" and according to the HD6445P4 datasheet it seems the size and some other things can be adjusted by software.

[@Epictronics1]

@@ruben_balea Yeah, YT is super flaky with notifications. Thanks. Finding that software is probably impossible

[@TravellingVikings]

Nice to see the 5151 back to operational condition.. I've got a few of these, their plastic has become very britle, just wondering if you have found a way to make them less brittle.. i.e. with some treatment..

[@Epictronics1]

I haven't had much trouble with brittle plastics on IBMs. Apples from the 90s however, are falling into pieces

[@richards7909]

With regards the worn bracket on the floppy drive, could you make a bushing to insert into it or is it far too small?

[@Epictronics1]

That's a good idea. If I wrap the peg in some aluminum foil, it might be large enough to stay in.

[@stamasd8500]

@@Epictronics1 or see the suggestion I just made in a separate reply: use PTFE tape (pipe thread tape used by plumbers)

[@sleveee]

where would a person find that matrix style screensaver you've got running there?

[@Epictronics1]

I think I found it here: forum.vcfed.org/index.php?threads/falling-letters-screensaver-for-dos.41667/

[@markmuir7338]

Finding a date online can be hard. I hear you, friend…

[@Epictronics1]

😆

[@gorauma]

I forgot to quip, that you have way more PCs than I have, though.

[@Epictronics1]

One can never have too many 😁

[@SianaGearz]

I don't know if that plastic holder piece can even wear. I think the plastic pins shrunk. Put them into a bag with a handful droplets of water for a few days, they're going to expand back into original shape. PA parts treated like that return to original condition (if they don't have sun damage) and become nigh on unbreakable. With 3D printing you have an issue. FDM printers aren't great at fine structures like these; and SLA resins don't have the right behaviour, the rigid ones are too brittle, and the tough ones permanently deform too easily, not springy enough. The only truly correct way is SLS or MJF, which is just the right type of material as well, being PA variants. There's any number of services which will do you SLS/MJF to order, including your sponsor. You might get some mileage out of an FDM printer with a 0.2mm nozzle. Maybe a good reminder to not get locked into a proprietary ecosystem where you can only get original nozzles and other parts and no replacements of wildly different spec. PA can be FDM printed but you need a dry feeder that sucks moisture out of the plastic while you're printing, and you need to experiment with adhesion, it will not bind to most common plate materials, but usually a piece of Kapton tape or Painters tape helps, or wood glue. PETG usually works just fine as a substitute though, and isn't quite as fussy. I would try a brass thin tube. It can be easily shaped a little to hold. If you have an RC modelling store nearby, they have all possible tiny sizes.

[@Epictronics1]

Thanks, I'll order a print from PCBWay if files are available. I have a plastic rod that might be the perfect fix for this. We'll try it out in an upcoming video.

[@FeliciaByNature]

I really like potatoes.

[@LFOSyncToo]

what's up with your mic sound? your voice keeps going in an out... strange.

[@Epictronics1]

I'll check, thanks for the feedback

[@e1woqf]

Wow. Premieres in 8 minutes and already 606 dislikes? Is this a YT glitch? Edit: obviously a glitch. Now as the video starts, the dislikes are gone.

[@Epictronics1]

One of many YT glitches...

[@SianaGearz]

The dislikes are not from KZbin, they come from the extension you're using that has to estimate them. In turn the server of the extension tries to estimate them from various sources, chiefly from the users of the extension behaviour. The estimate is typically wildly off as well, just as a rule, but it does show a significant trend. The behaviour between users of the extension and the general KZbin public isn't identical even when the sentiment is, because people don't click a button they know doesn't really do anything.

[@e1woqf]

@@SianaGearz Very interesting, thanks!