Alphatronic P2 48k Repair

[fing972]

Hi,
Apologies for my English, I bought a P2 with 48k and, after repairing the power supply and doing a recap of many tantalum capacitors on the boards, I started doing some tests on the software side. I struggled a lot to create a floppy with Basic and a floppy with Cpm for 48k.
After starting the Basic and Cpm floppies, I ran into other problems, one is the "D" key which doesn't work and then I have an imperfection on the original green phosphor monitor which displays the upper part with sparser interlines, while the lower characters are compact.
I have removed the "D" button and would like to replace the Hall sensor. I also removed the "SM" key (which is perhaps less useful than the "D" key) and will probably swap them. But does an alternative to the Hall sensor exist at the moment?
Is it possible to have more information on how the replacement with the TLE4905 was achieved?
I saw in the photos that electronic components have been added to the sensor.
While for the monitor is there a trimmer internally that regulates the height of the character line spacing?
Thanks for any support.

 

[ajacocks]

Welcome to the forum @fing972 . Your English is fine!

Would you post some pictures of your machine and the work that you are doing?

- Alex

 

[RetroAND]

Hi,
Apologies for my English, I bought a P2 with 48k and, after repairing the power supply and doing a recap of many tantalum capacitors on the boards, I started doing some tests on the software side. I struggled a lot to create a floppy with Basic and a floppy with Cpm for 48k.
After starting the Basic and Cpm floppies, I ran into other problems, one is the "D" key which doesn't work and then I have an imperfection on the original green phosphor monitor which displays the upper part with sparser interlines, while the lower characters are compact.
I have removed the "D" button and would like to replace the Hall sensor. I also removed the "SM" key (which is perhaps less useful than the "D" key) and will probably swap them. But does an alternative to the Hall sensor exist at the moment?
Is it possible to have more information on how the replacement with the TLE4905 was achieved?
I saw in the photos that electronic components have been added to the sensor.
While for the monitor is there a trimmer internally that regulates the height of the character line spacing?
Thanks for any support.

Hello,

Sorry if this isn't the answer you are seeking, but nevertheless that's how it is.

At this point there isn't still any solution for those keyswitches, so replacing the switch from a less used key is the only solution until somebody finds a cure for them.

About the monitor, I don't remember if it was a rebadged AIWA or a SONY (more likely the former), but it is very common among Japanese computers. Maybe you could first find the reference by watching magazines, then using it to search the service manuals.

Where are you from? I ask because there are many localized variants still unaccounted for.

Have a nice day

 

[RetroAND]

Welcome to the forum @fing972 . Your English is fine!

Would you post some pictures of your machine and the work that you are doing?

- Alex

There was a German 8085-based computer made by a company called SKS, which was called KISS (Keep It Simple Stupid) and was orange. It proved successful as the design was licensed by multiple companies such as Triumph-Adler, Hell or ITT. TA used the P1 (single floppy, 6KB ROM, 32KB DRAM, 1-2KB VRAM) and the P2 (two floppies, 6KB ROM, 48KB DRAM, 2KB VRAM) to launch its Alphatronic brand. It was later overhauled by the P2U (64KB DRAM), P2E (or 2S, I can't remember, but it was different as it was single-board while the whole series is backplane-based). The series revolved later on the P3, P4, P30 and P40 which were a disappointment and lost to the PC. Still, during the firsts years the Alphatronic Px series posed a very difficult competition to IBM in Germany and Italy although not much elsewhere. Sometimes a localized unit apears and that's all. German and Italian models are common, while the rest could be quite rare.

I hope this illustrates what a P2 is.

 

[fing972]

Hi,
I am sending the image of my Alphatronic P2 which I have currently reassembled and it seems to work, at least from some preliminary tests.
I'm from Rome, and I collect vintage computers and consoles.
This model was unknown to me until I found it not working in a flea market.
It had a faulty power supply, i.e. the part that regulated the 5V needed to be repaired (replaced a diode, a transistor and the LM339) and it had several shorted tantalum capacitors and I carried out several replacements.
Having cleaned the heads of the 2 floppy drives, I exchanged 2 keys and finally repaired some plastic parts broken due to a collision.
In Italy I don't think it's a very common computer so I decided to invest in repairs and put it in my collection.
I recreated 2 floppies using my old 286 PC with 360K drive.
On the first floppy I put the cp/m 48k version and on the second the basic (my favorite development language).
On this occasion I wanted to ask if there is a manual for basic language sks 1.0.6 (this is the version I have) and if it is normal that I cannot format floppies and write files using P2 (the floppies were created by PC).
Regards