I just found out that I need different eproms (the 27c4001 types to
be precise); which I have no idea if the c64 promenade eprom burner
can reproduce or not being the SIZE OF THEM and the fact that they are
NOT LISTED on the list of available eproms for use with the hardware.
 So I'll have to get my hands on an affordable, used but working PC
EPROM BURNER of some type to perform the burning function of these
chips.
 Also, I still have yet to find out the specifics of which diodes I
will be needing for the support components on the pcb.
  I got the boards themselves yesterday in the mail (THANK GOD) so at
least that's out of the way.
  So it's like you said, still got a few things to work out
here.......


  Thanks for the clarification!

  Charles

In article 
<de6c0793-4c98-4a8c-ab19-4080e6065825@g21g2000yqc.googlegroups.com>, 
shifty_butch@hotmail.com says...
>...
> So I'll have to get my hands on an affordable, used but working PC
>EPROM BURNER of some type to perform the burning function of these
>chips.
>...


F.Y.I.

I'm not sure what you consider affordable, but maybe these NEW 
programmers would be useful?
http://www.mcumall.com/comersus/store/comersus_viewItem.asp?idProduct=42
82

Lots of choices available...
http://www.mcumall.com/comersus/store/comersus_searchItem.asp?strSearch=
programmer

I have an old PC ISA based programmer that works fine, but I've been 
looking at these more modern replacements...  They seem pretty 
reasonably priced.

I haven't bought one yet because the number of EPROMs I burn in a year 
has been declining for quite some time...  The only time I use it these 
days is to fix a very old ROM/PROM/EPROMs with bit rot.  Wow was I 
surprised to find a mask ROM with a missing bit or two.

Anyway, hope this help!

-- 
Some Guy

Some Guy wrote:
> In article
> <de6c0793-4c98-4a8c-ab19-4080e6065825@g21g2000yqc.googlegroups.com>,
> shifty_butch@hotmail.com says...
>> ...
>> So I'll have to get my hands on an affordable, used but working PC
>> EPROM BURNER of some type to perform the burning function of these
>> chips.
>> ...
>
>
> F.Y.I.
>
> I'm not sure what you consider affordable, but maybe these NEW
> programmers would be useful?
> http://www.mcumall.com/comersus/store/comersus_viewItem.asp?idProduct=42
> 82
>
> Lots of choices available...
> http://www.mcumall.com/comersus/store/comersus_searchItem.asp?strSearch=
> programmer
>
> I have an old PC ISA based programmer that works fine, but I've been
> looking at these more modern replacements...  They seem pretty
> reasonably priced.
>
> I haven't bought one yet because the number of EPROMs I burn in a year
> has been declining for quite some time...  The only time I use it
> these days is to fix a very old ROM/PROM/EPROMs with bit rot.  Wow
> was I surprised to find a mask ROM with a missing bit or two.
>
> Anyway, hope this help!

I've had to replace quite a number of mask ROMs in various retro computer 
and consoles of late. Seems they are coming to the end of their life.

Glad people have taken the time to dump ROM's for virtually every platform 
so that failed ROM repairs are relatively simple.

I have a Willem programmer and for the price I paid it's been a good unit 
but if I was to program a lot of ROMs I would go for something more modern 
with better capabilities and support - and as you said they're not that 
expensive. 

Clocky <notgonn@happen.com> wrote:
> I've had to replace quite a number of mask ROMs in various retro computer 
> and consoles of late. Seems they are coming to the end of their life.

> Glad people have taken the time to dump ROM's for virtually every platform 
> so that failed ROM repairs are relatively simple.

> I have a Willem programmer and for the price I paid it's been a good unit 
> but if I was to program a lot of ROMs I would go for something more modern 
> with better capabilities and support - and as you said they're not that 
> expensive. 

I thought masked ROMs didn't go bad on account that the code is written 
into the circuitry instead of charges as with EPROMs.


-- 
David Griffith
davidmylastname@acm.org   <--- Put my last name where it belongs

David Griffith wrote:
> Clocky <notgonn@happen.com> wrote:
>> I've had to replace quite a number of mask ROMs in various retro
>> computer and consoles of late. Seems they are coming to the end of
>> their life.
>
>> Glad people have taken the time to dump ROM's for virtually every
>> platform so that failed ROM repairs are relatively simple.
>
>> I have a Willem programmer and for the price I paid it's been a good
>> unit but if I was to program a lot of ROMs I would go for something
>> more modern with better capabilities and support - and as you said
>> they're not that expensive.
>
> I thought masked ROMs didn't go bad on account that the code is
> written into the circuitry instead of charges as with EPROMs.

Every IC has the potential to go bad, mask ROM's are no exception.

They get pretty warm too, and thermal cycling will get every chip sooner or 
later. Mask ROMs don't tend to suffer from bit rot, but they do fail. OTP 
ROM's and EPROMs , which are sometimes used tend to suffer bit rot 
progressively whereas mask ROM's just do a sudden death.

Reading out a failed mask ROM often results in data that doesn't resemble 
the original content in the slightest unlike a bitrotted E(PROM).