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Vintage Computers Any vintage computer systems, calculators, video games etc., but with an emphasis on 1980s and earlier equipment. |
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25th Aug 2010, 12:17 pm | #1 |
Rest in Peace
Join Date: Jun 2006
Location: North West Northamptonshire, UK.
Posts: 346
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Anita Calculators
I have received a PM from forum member Woodchips who has a DIY Anita Mark 8 calculator. Are you able to post some photos of the boards you have?
Do you have a keyboard and a case and a motherboard? As to your missing power supply, I am not certain if I have a circuit diagram as the few I was allowed to retain are packed away. I do have a complete machine, but I doubt it will work. Spare parts will be difficult to obtain, particularly dekatrons, trigger tubes,and 19(or18)Meg resistors. 1N4148 diodes could replace the selenium twin pack logic diodes. The power supplies used an Advance constant voltage transformer,to provide +495v,+20v, and minus 125 volts. PM me your phone numberand we can perhaps take this further. Regards ALAN |
28th Aug 2010, 6:30 pm | #2 |
Octode
Join Date: May 2010
Location: Grantham, Lincolnshire, UK.
Posts: 1,176
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Re: Anita Calculators
Alan, I have sent another PM, did you receive it? Bob.
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2nd Nov 2010, 12:11 pm | #3 |
Hexode
Join Date: Mar 2009
Location: Worthing, Sussex, UK.
Posts: 277
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Re: Anita Calculators
I have just inherited an Anita Mk8. All the numbers light up and the ring counter goes around but that's all. It's been in a loft for I guess at least 30 years so I'm not surprised.
Does anyone have any circuits - I'd love to get it going again. I remember buying the counter boards, both the cold cathode and the transistor versions, from the junk shop that used to be in Deptford in the late 1970s. Ging |
2nd Nov 2010, 9:23 pm | #4 |
Rest in Peace
Join Date: Jun 2006
Location: North West Northamptonshire, UK.
Posts: 346
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Re: Anita Calculators
Hi
I'm afraid I dont have any circuits for the Anita Mark 8, but spent 10 happy years repairing various models of Anita, but this was more than 30 years ago. You say you purchased boards in the 1970's. Do you still have them? They could be vital to getting the machine working because of the lack of spares. First thing to check is that the keep alive electrodes, "night-lights" are all illuminated in every trigger tube. These are fed from the -125volt line through 19Megohm resistors, and go high resistance. Ones in excess of 25Meg must be replaced. The machine contains about 180 trigger tubes!! Other problems include high forward resistance of the selenium logic diodes, the trigger tubes themselves, and dirty contacts and rotors on the keylines. Critical voltages are +495, +20, and-125. The keyboard is earthed, but the power supply is fed by an Advance constant voltage autotransformer, and therefore not isolated. I am intending to write a quick repair guide to the Mark 8, but it will take a little time to compile. If you wish to contact me please PM me your phone number, for a chat. Regards ALAN |
15th Nov 2010, 11:21 pm | #5 |
Banned
Join Date: Nov 2010
Location: GB
Posts: 2
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Re: Anita Calculators
I have several Mk 8s, a 9, a 10 an 11 and a 12 in various states + lots of service info and diagrams . A 1011 , a rusty `1011P in bits. etc etc. It'll all go in a skip when I'm gone, no doubt.
I can remember how an 8 works but a bit rusty on 9 up. Too old to bother now. |
16th Nov 2010, 1:18 pm | #6 |
Pentode
Join Date: Aug 2010
Location: Sheffield, South Yorkshire, UK.
Posts: 163
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Re: Anita Calculators
I wouldn't mind a Mk. 8 if there are any left over from Alan mobbing you
If you want I could send a courier round to pick them up and catalogue and dole them out here to other interested members. Thanks for posting by the way - you must have been searching 'Anita' ?? |
16th Nov 2010, 4:55 pm | #7 |
Octode
Join Date: May 2010
Location: Grantham, Lincolnshire, UK.
Posts: 1,176
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Re: Anita Calculators
Hello, would be interested in one, or more, of the various models, try and get my Mk8? running. Yes, interesting post, thanks, Bob.
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16th Nov 2010, 6:24 pm | #8 |
Hexode
Join Date: Mar 2009
Location: Worthing, Sussex, UK.
Posts: 277
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Re: Anita Calculators
I'l be interested in any info you have on the Mk8 and the 1011, of which I have a working example. Sadly I painted in with gold spray paint when it was 'fashionable' to do so. about 1977 I think.
Ging |
16th Nov 2010, 6:51 pm | #9 |
Rest in Peace
Join Date: Jun 2006
Location: North West Northamptonshire, UK.
Posts: 346
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Re: Anita Calculators
A much bigger collection than I have. If you are selling, the Mark 10 would be of great interest, as it can convert into £,s,d. from decimal. I would also be interested in any documentation you have. As you will not have access to the private message system, can you contact my by the forum email system.
The 1011P was always problematic and the chance of saving it is poor, but maybe possible. The ones with trigger tubes will only be repaired by canibalisation. What model is the 1011? Can you quote the serial number? I would certainly like to see your collection if possible.Whilst you are a fair way from me it is straight up the M6. Regards ALAN |