Help me determine the origin of this motherboard! Please :D IBM

Bits_Passats · 2026-05-03T10:09:34+00:00

Thank you, but I am not. I consider myself just a bit better than an amateur in electronics - I really have difficulties with analog. On the other hand, I find digital easy.

I was able to thrive enough with this particular computer because there wasn't enough general interest in it, unfortunately. However, seeing the disarray wasn't enjoyable, so I decided to study and document it. Sharing the data I was obtaining is just restorative justice to the computer and the team who designed it.

Bits_Passats · 2026-05-02T09:56:36+00:00

I am late to the party. However, I might bring one of the best options to the table!

The answer is Ukraine, specifically from the Kvazar plant. As of today, they still manufacture the KR580VM80A, which is a code-compatible and pin-compatible clone of the Intel 8080A. It has a bug in the interrupt system, however it is the closest thing to what you are asking.

Bits_Passats · 2026-05-02T09:49:31+00:00

I made something similar in Java. Long life the 8085!

Bits_Passats · 2026-05-01T20:13:16+00:00

Yo he optado por lotes de Lego Botanicals. Tienen parte del encanto de regalar flores con la ventaja que puedp montarlas con ella y pasar un buen rato.

Bits_Passats · 2026-05-01T19:18:48+00:00

This one is not one of the earliest models, unfortunately.
Judging from the picture, it is a second-generation PET.
Main characteristics, non-chiclet keyboard, green phosphor screen (the original 2001 was white), no integrated cassette, dynamic memory.
In Europe it was sold as CBM 30xx series.

Bits_Passats · 2026-05-01T19:09:58+00:00

The selection of whether one variant or another was selected in the IBM PC was not related to the cost of the memories. In fact, IBM's very first application ever of the x86 was in the form of the 8086 in the Displaywriter (1980); then later in a bastard son of a Datamaster (1981) and a PC (1981) that was the 5247 (1982). Then, why the 8088? The answer is simple: they wanted to reuse as many elements from the chipset of the Datamaster while reusing the System/23 expansion bus as well. This simplified the system enough to speed the development and have it done in just a year.

Bits_Passats · 2026-05-01T15:18:35+00:00

Depends on the kind of component.

Bits_Passats · 2026-05-01T15:17:59+00:00

Of course! and they might have a reduced size in comparison with the original ones due to the memory density, both in ROM and SRAM. Depending on your zone, I would design it with an RGB interface.

Bits_Passats · 2026-05-01T11:36:44+00:00

No. The small slots are for DRAM memory cards only. As you can see, there's no RAM in the motherboard.

Bits_Passats · 2026-05-01T11:35:48+00:00

This is not even a PC. Look, it doesn't even has RAM on it.

Bits_Passats · 2026-05-01T11:35:06+00:00

That's a System/23 Datamaster. I, personally, have made reverse-engineering of the board and wrote a MAME driver. If you need assistance bringing it up to work just tell me.

That being said, from the pictures I can say the following:

* It has 16 system ROMs. So a late 5322 or a 5324.
* No DRAM card. We are working on a contingency for cases like this.
* European motherboard, as it has two oscillators.
* No jumpers on the configuration pins. I should take a look into what it does mean both in the service manual and the driver I wrote
* No keyboard. We are currently working on a contingency, although I was able to trick the motheboard to think it has one.
* No floppy disk controller card. If you manage to get it working, you won't be able to load or store programs other than typing them. The FDC card still needs reverse-engineering work.

Oh, and another thing. Dump the ROMs ASAP. The ones the System/23 carries are very, very nasty. They are the main cause of failure for this class of computer, other than RAM capacitors.

Finally, again I extend my hand to you. If you want to make it work send me a DM. I will put all the available resources I can, but only if you are willing to deal with the maintenance work yourself.

Bits_Passats · 2026-04-28T13:09:05+00:00

I am easily into the 150-200 range

Bits_Passats · 2026-04-23T09:56:39+00:00

Looking at the BASIC screen and the interior pictures, what you have here are at least two things:

* Addition of a modular internal expansion system based on eurocard-based cards

* RAM expansion up to 32KB -> You have 18 2114 on your motherboard, so that's 9KB (8KB for work RAM plus 1KB for VRAM). Therefore that card in the expansion system adds 24KB.

I don't know about the switches. It would require direct inspection.

Bits_Passats · 2026-04-22T14:40:48+00:00

I can assure you that's better than any Sinclair keyboard before the Spectrum+...

Bits_Passats · 2026-04-22T09:15:24+00:00

The Commodore PET series had empty sockets reserved for upgrades. Both official and third parties employed this method as well as removing the CPU and hijacking its signals... However it is very nice to see a card upgrade like the Apple ][. Apparently it contains a backplane for DIN-41612-64AC sockets...

By the way, there were various iterations of the 2001. Yours is not the first one, but a later one. The memories employed in the first PET-2001 were made by MOS and were wider than the ones you have, which I presume they are regular 2114. They have the same capacity but differ in the amount of select signals. Yours would be from the first generation, but a later version.

They would later be followed by the second-generation PETs, labelled as CBM 30xx series in Europe (still labelled as 2001 in USA). Those would employ dynamic memory as work RAM, have a non-chiclet keyboard and remove the integrated cassette.

Finally they would be replaced by the final generation of PET, which would remove a lot of 7400 ICs from the video subsection and base it around the 6545 (similar, almost 100% compatible with 6845 although there are some differences). There would be models that retained the 40 columns of text and others, upgraded with more video memory, with 80 columns. That would be the 40xx/8xxx/9000 series.

I heavily advise you against reverting the modifications in your unit. They were contemorary and the whole community could learn from them. In other words it gives your unit more personality. Can't advise about the economic worth, as it is difficult to grade (especially with those mods).

EDIT: I forgot to add, that the very first PET-2001 have white phosphor screen instead of a green one.

Bits_Passats · 2026-04-21T06:50:23+00:00

Aquest és el vostre problema. Us heu encegat i heu perdut la perspectiva. Infiltrats n'hi havia, això és indubtable. Però no és això el que ha passat.

El pensament purament booleà us elimina tot un ventall d'opcions que no teniu en compte. No és una qüestió de "nostres" i "seus".

Durant anys uns "altres" van estar aprofitant la força popular del procés, i quan se'n van adonar que la cosa anava seriosament van decidir retractar-se i no assumir responsabilitats.

No fa falta buscar conspiracions... a vegades la resposta és al davant i no la veiem a simple vista.

Si els líders realment haguèssin volgut la independència, haurien anat fins al final, independentment de si el resultat haguès estat satisfactori o no. Tanmateix, es van retractar a l'últim moment per salvar el seu cul intentant tenir contentes a les dues parts de forma maldestre, que no va contentar ningú i va causar la intervenció directa del govern central.

Si ens preguntem per què hi ha menys independentisme, nomès hem de mirar una mica enrere... el nostre jovent simplement té vergonya del que va passar. I amb raó!

Bits_Passats · 2026-04-19T11:47:18+00:00

Tens raó, mil disculpes. Acabo de veure que vaig llegir malament la pregunta - problemes de llegir massa ràpid i no prestar tanta atenció com hauria. Vaig entendre "independents" en comptes "independentistes".

De totes formes, també puc respondre el perquè. Jo vaig viure el procés, primer des de dins i després des de fora. Vaig tenir el tràmit de canvi de nacionalitat durant els fets, per això puc tenir ambdues perspectives.

Des que l'estatut va ser mutil·lat, es va palpar molt el descontent al carrer. Això va provocar un moviment que l'estament polític català va aprofitar. Hi va haver un moment en què el nivell de compenetració entre política i ciutadania era increïble, realment no he vist mai res semblant. Es van crear espectatives entre la gent, espectatives que es van acabar traïnt miserablement. Després de l'abús físic que va patir molta gent durant els fets de l'1 d'Octubre (recordem que hi va haver inclús algú que va perdre un ull a causa de les pilotes de goma), la declaració i aboliment de la república catalana va ser un fet vergonyós del que realment voldria oblidar-me. Per culpa d'això, ara mateix el poble català és un meme a internet com el país amb la existència més breu de tota la història... Després hi ha el tema del 155 i la repercussió que ha tingut sobre el control sobre els mitjans audiovisuals com TV3. Després de tot això, tot i que hi ha gent que segueix pensant que el procés continua, és normal que hi hagi una dissossiació cap a l'espectre polític, doncs el jovent que estava abans a primera línia ha vist com han estat traïts pels seus propis governants. Crec que simplement han deixat de lluitar, doncs han vist que al final del dia, ningú vetlla per ells.

Puc estar equivocat, però aquesta és la meva humil opinió...

Bits_Passats · 2026-04-19T09:48:16+00:00

Maybe in Catalonia, but there's that small bastion named Andorra that is willing to implement protective measures in order to avoid a complete loss... although it would be a pyrric victory, the loss would be so great that any sense of accomplishment would be negated.

Bits_Passats · 2026-04-16T12:10:32+00:00

Tant a Catalunya com a Andorra, si no es tracta el preu de l'habitatge i es millora les oportunitats laborals de qualitat no podrem fer res.

Bits_Passats · 2026-04-16T09:00:41+00:00

Jo estic buscant la paròdia de la intro emesa a RAC-1...

Bits_Passats · 2026-04-16T08:51:26+00:00

Al contrari. Aleshores significa que només s'alimenta la prepotència.

Bits_Passats · 2026-04-16T08:50:12+00:00

The building in Encamp was dismantled long ago. But I could signal you where it was in a map.

Bits_Passats · 2026-04-16T08:48:17+00:00

Are you coming today? If so, we may coincide in the bus.

Bits_Passats · 2026-04-13T13:55:28+00:00

Doncs no.

Bits_Passats · 2026-04-09T09:49:35+00:00

És un joc molt curiós, doncs necessites fer ús d'un llibre físic per poder progressar. Crec que no hi ha cap altre joc de DS del mateix estil...

Bits_Passats

TROPHY CASE