Posts by nilseuropa

Quote from RetroGuy

Quote from nilseuropa

Yesterday made me these two happy:

PET-1 from hans
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* CRTC logic had multiple bad ICs
* video RAM traces were eaten up by rust
* several ICs were missing legs ( including the 6522 )
* vertical deflection circuit of the CRT was faulty
* still need to write the BASIC ROMs

PET-2 from the Museum

PXL_20230123_194737871.MP.jpg

* the floppy controller card killed some of the MOS ICs
* it was an easy fix
* FDC still needs attention

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It seems the R2D2 left to the desk wants to play with the PET

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Then I shall let it play with it.

Yesterday made me these two happy:

PET-1 from hans
PXL_20230123_193840967.jpg

* CRTC logic had multiple bad ICs
* video RAM traces were eaten up by rust
* several ICs were missing legs ( including the 6522 )
* vertical deflection circuit of the CRT was faulty
* still need to write the BASIC ROMs

PET-2 from the Museum

PXL_20230123_194737871.MP.jpg

* the floppy controller card killed some of the MOS ICs
* it was an easy fix
* FDC still needs attention

This made me happy today:
https://info.computerhistory.org/apple-lisa-code

I have modified the closet in the workshop to power my CNC and 3D Printer. I'll call it "the replicator". 🙂

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Quote from Toast_r

Quote from nilseuropa

I have only found this one so far:

https://www.nightfallcrew.com/…drive-800k-dd-dsk-ctl-p2/

These Tandon TM 100 are single sided (only one R/W head cale connected).

So these seem to be 200k, like mine.

But take a look at the ad: The advertised capacity means both drives.

The 800k version is double sided, 400k per disk.

I have the 400k version - single sided, 200k per disk.

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Micro Peripherals Inc. Model 52

https://osiweb.org/manuals/MPI_B51-B52_Product_Manual_Long.pdf

Quote from Toast_r

Quote from nilseuropa

It has a plastic enclosure, and the Bezel is hiding two cut-outs what seems to be 5.25" drive bays.

AFAIK, Commodore never used these bays to install drives there.

I thought about doing so, but this would need a fitting bezel.

Quote from nilseuropa

PET-2 is bundled with a rather interesting item, a Computhink 800k dual drive with controller card

Mine uses only 40 track single side, with 200k per disk.

Are these 80 track double side drives?

I would be interested in details.

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I have only found this one so far:

CompuThink DD DSK | nIGHTFALL Blog / RetroComputerMania.com

I have picked up two 3032s on the weekend. One from hans ( PET-1 ) and the other from the Museum ( PET-2 ).

PET-1 has some serious issues, the board is pretty rusty, some legs are missing here and there, but not hopeless.
I have to fix the display logic first, I did replace the video RAM and couple of logic gates, there is some progress.

It has a plastic enclosure, and the Bezel is hiding two cut-outs what seems to be 5.25" drive bays.

Does anyone of you know what is the story behind these bays? The machine was manufactured in 1979 in the States.

PET-2 is bundled with a rather interesting item, a Computhink 800k dual drive with controller card:

The caps are shorted on the FDC, but I was able to start the machine by replacing the CPU, so now I can use it as a reference to diagnose and repair PET-1.

( As these drives are standard Shugart, I plan to fix them separately from the FDC and then try to repair the controller card. )

Meanwhile I am in the middle of moving into my "Neustes Etwas", namely my new studio:

Tada...

Quote from Muffinmann

Und wieder einen Schritt weiter...

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Sorry, I might have missed it, but where did you get the keyboard?

EP 128k with EXDOS FDD controller

There were some issues with video stability and the membrane keyboard, all fixed.

Videoton TVC 64k ( dumbed down version of the Enterprise, without the special graphics and sound chips )

Restoration in progress

I decided to rebuild the PSU, the original design is crappy.

I had no chance to visit my father since September last year. He has got an aggressively progressing Parkinson's disease, but we were able to do some retro restoration together this Christmas. I must confess, I cried really hard that night.

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Quote from ferrytale

@nilseuropa: Very nice Osborne with a shiny new Tube!

I was lucky enough to get such a little CRT module with an amber tube.

The module takes composite video as well as VGA signal up to 800x600!

ooh, that is exciting. what are your plans with it?

I think the only documentation you would ever need is the schematics. I am happy to share that. I'm also around and happy to help.

I have found the schematics for the Motorola MD1000, adjusted some resistor values to accommodate the Samsung CRT. It works nicely in place of the NEC.

Quote from MarkL

I thought there was an out-of-the-box secondary CRT jack on the O!'s front panel

If you have the ScreenPac upgrade installed then yes. I am not that lucky.

I am determined to fix the original CRT Display, so I have bought two 5.5" mono TVs.

Unfortunately I can't find the datasheets for the CRTs, but as they are made of glass I was able to check that the tube connector pinout is a match. Also the heater elements resistance seems to be equal in all cases.

I was able to verify that the original CRT is indeed dead as it did not give any sign of life in any of the mini TVs.

The voltages to open it and get the electron beam going are present also on the original board. So I tried one of the "new" tubes, but still no image.

Meanwhile I have given another shot for my TTL to Composite converter and the result was a lot better this time:

It needs a lot more fiddling around to have proper signal proportions, but it proves the concept. This could be an okay-ish fallback option if I am not able to fix the original, although I wouldn't be very happy with it. ( I would know. )

Fixing up an Osborne-1. Again... This time it seems the CRT gave up.

I have also tried to build a rudimentary composite output card for it,

but I failed.

Also nicht heute, aber...

My wife wrote a collaborative sci-fi theater piece and asked me to build some props. ( Apparently I love building props. )

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Quote from jdreesen

Quote from nilseuropa

On the weekend I'll receive a PDP dual 8" drive, I hope I can hook it up as well, if not, then there will be some trading going on for sure )

An RX01 or RX02 ? Cannot be used on a PC, it has internal electronics that are completly incompatible .

I would exchange for 2 normal 8" drives, but the distance....

Yeah I figured, that's why I'll probably trade it. It looks like this:

I have finally built several things to make my daily ongoing more cheerful.

A new workstation on electric standing desk with enough room for an extra retro machine:

PXL_20221101_154738450.jpg

I have tidied up a bit my Greaseweazle setup, slimline 3D printed enclosure and a single bay 5.25" external 40 track drive to connect. ( Apart from this drive I have other single drive units in cases e.g. Amstrad 3", IBM 3.5", Disk ][ etc... ) On the weekend I'll receive a PDP dual 8" drive, I hope I can hook it up as well, if not, then there will be some trading going on for sure )

Quote from xesrjb

I think you have to add „megahit“ while starting to have the cheat mode…

xesrjb

Yes, that argument was available in version 1.3 - here I have to state the display mode as an argument. CGA

Nils to space center, we've got lift-off!

Thank you hans for pointing out the drivers being OC. The FDC outputs were looking fine on the oscilloscope. As soon I have replaced the drivers on the FDD backplane it booted off from it's original floppy drive.

Hard drive is beyond salvage, but I think that's all right.

My HXC arrived couple of days ago. I can confirm that the FDC won't issue a seek command.

Not mine, the Museum got it from a very generous donor, but I though it is worth sharing:

Two Sharp MZ5600 computers, with matching keyboards and mice, two color monitors, external 8" FDD and HDDs.

The two boxes next to the computer contain a massive amount of original documentation, expansion cards and system diskettes.

And one of them boots straight into EOS-16 from floppy.

I've got a TEAC FD235HF-5240 as a drop in 3.5" FDD ( also used in my Amiga disk imager ).

According to The Artful Company, the Ready signal should be available on pin 68 of the controller chip.
I have double checked it with scope and after the motor reaches stable RPM that line goes high.

DF0/DF1 selection is on actual jumpers on this drive. I've cut the Disk Change line and patched the Ready signal in:

Aaaaaaand, nothing.

Thanks to Dr_Diesel, Shadow-aSc, hans and cosmicboy my Euro XT has arrived safely.

I'll start to work on it soon once I find my XT keyboard. Cleaning in progress.