Strange Character ROM connection

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Strange Character ROM connection
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Image icon Apple II+ Clone (Unicom)2.27 MB

I've recently restored this Apple II+ Clone. It has a UM2316 as character ROM. The Chip itself is replaceable with a 2716 eprom. But none of the standard Apple II Character ROMs works.

The connection between the ROM and the 74166 totally diffrent from what it is in a regular II+.

Does anyone regognize this board? Are there any Informations / ROM images available anywhere?

 

 

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It's a generic clone and will

It's a generic clone and will use CG image all the clones use. If you don't have an image from a clone let me know and I can dump one from one of the clone boards I have here.

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I've the same Motherboard...
David_M wrote:

It's a generic clone and will use CG image all the clones use. If you don't have an image from a clone let me know and I can dump one from one of the clone boards I have here.

Hey David, could you send me the dump too, please. I hope you still have it ;-) And by the way: What are you burning the ROM with? I currently only have one EZP2019 USB programmer, but I don't have that much experience with it yet... Can I use a 2716 EPROM despite the incompatibilities described by mafrmt00? Or must I use a UM2316 because of different pin assignments or so? Thank you very much for your help and Best Regards Georg
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A 2316 is not programmable,

A 2316 is not programmable, it is a mask ROM.

The programmable version, 2716, requires +25V programming voltage, which is not supplied by most of the low-cost programmers now available. Refer your programmer's documentation for whether it can supply such a voltage (or better yet, look up any devices in its published device list).

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robespierre wrote:A 2316 is
robespierre wrote:

A 2316 is not programmable, it is a mask ROM.

The programmable version, 2716, requires +25V programming voltage, which is not supplied by most of the low-cost programmers now available. Refer your programmer's documentation for whether it can supply such a voltage (or better yet, look up any devices in its published device list).

 

There are versions of the 2716 that require +21V or less.  27C16 and some marked 2716 will work, it just depends.  TI also had a 2516 back in the day that only required +12V for programming if I remember right.

 

Also some people have had luck supplying their own 25V programming voltage and gotten newer programmers to work.  FWIW, I have an older MiniPro TL866CS which I've successfully programmed a lot of 2716s with.  Others claim it doesn't work for them.  Most report the newer TL866-II does not work.

 

 

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softwarejanitor wrote
softwarejanitor wrote:
robespierre wrote:

A 2316 is not programmable, it is a mask ROM.

The programmable version, 2716, requires +25V programming voltage, which is not supplied by most of the low-cost programmers now available. Refer your programmer's documentation for whether it can supply such a voltage (or better yet, look up any devices in its published device list).

Dear robespierre, dear softwarejanitor,

have many thanks for your answers.

yes, I know, that the 2316 is a ROM (I thought it would be a PROM, that could be programmed once...).

But ideed, I planned to exchange the 2316 by an EPROM, like 2716 or better by an EEPROM, like a 27/28C16.

And yes, my search in the net brought me also to the TL866 programmer...

Okay, I'll search a while for a TL866A or'll use a TL866 II to use it for the newer 27/28C16. Does this function good?

 

Sorry for my pure english...

 

Best Regards

Georg

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That is a fairly common

That is a fairly common Unitron - style (or true Unitron) motherboard.

There is no real difference in Character Generators between them.

If you need one, I can supply an image, or a burned 2716 EPROM in exchange for you sending me a blank.

 

Most USB programmers will fail at programming 2716s.  I have a vintage burner that works on 2716s.  100% success rate.

I'd be happy to help.

 

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Image for 2716
Dear baldrick,
baldrick wrote:

That is a fairly common Unitron - style (or true Unitron) motherboard.

There is no real difference in Character Generators between them.

If you need one, I can supply an image, or a burned 2716 EPROM in exchange for you sending me a blank.

 

Most USB programmers will fail at programming 2716s.  I have a vintage burner that works on 2716s.  100% success rat

Yes, for the first step I would appreciate if you could send me a image/dumb for the 2716. In the meantime I've researched a lot of information about "burning" EPROMs and found a programmer (TL866CS) that should be able to do this. But I am now of the opinion that an EEPROM 28C16 would be easier to deal with. Do you think that such an EEPROM works? And: Do you have a circuit diagram for the Unitron motherboard? There aren't that many differences between the original Apple II motherboard and the Unitron, except of the ROM board in slot 0 - and the character ROM is different: the original Apple II character ROM only has a 5-bit output (Q1-Q5). They use a 2513 ROM there. When reading the 2316, I noticed that the first two bits (Q0 and Q1) are obviously not used. I have the ROM dumb from the original Apple character ROM and if I ignore the first two bits and treat Q3 of the 2316 as Q0 then the dumbs look 90% the same :-) I would be very happy if you could send me the image of the Unitron 2716. Thank you so much – especially for the offer to burn an EPROM for me!!! Best regards Georg
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Be aware
Goonies wrote: Dear baldrick,

ost USB programmers will fail at programming 2716s. 

found a programmer (TL866CS)

 

The TL866CS is the old version  which is difficult to find, if you don't have that one already.

What is sold today is the TL866II+ which can't program some of these old eproms.

 

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tolderlund wrote:Goonies
tolderlund wrote:

The TL866CS is the old version  which is difficult to find, if you don't have that one already.

What is sold today is the TL866II+ which can't program some of these old eproms.

 

Yes, you're right – I found it used :-)

Best Regards

Georg

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