[Coco] Re: EPROM eraser wanted

[Stephen H. Fischer]

Hi,

Gene Heskett wrote:
> On Saturday 15 April 2006 14:36, Stephen H. Fischer wrote:
>> Hi,
>>
>> If you have a good lighting store around, you can try and order just
>> the lamp tube.
>>
>> Then you can put the lamp in place of the regular florescent with the
>> same size in any suitable fixture.
>>
>> The EPROM eraser is just an ordinary florescent tube with no interior
>> white coating.
>>
> Correction, its made from quartz, as the glass filters quite a bit of
> the UV light needed to erase an erasable eprom.  I once taped a 27C64
> to a "black light" tube

I have plenty of "Black Light" tubes, they are safe to look at with your
eyes.
I used the G8T5... for exposing printed circuits also.

Two different types of tubes.

The black light tubes convert the "short" UV rays to "Long" wave rays not
allowing the needed "short" waves out.

> , removing it once a day to check to see if it
> was erased.  It took about 2 weeks to get the last bit set to a 1, and
> apparently that wasn't enough as subsequent programming sessions left
> bits that shoulda been a 1 at zero when done.  So I ordered an eraser,
> which did that job in 18-20 minutes.  No more ghost zero's in my burns,
> with a homemade burner I'd built.  ISTR I paid about $70 for it at the
> time.
>
>> It is clear glass with small balls of mercury inside.
>>
>> You do have to use it in a way that you cannot look at when it is on
>> as it will harm your eyes.
>
> The eraser I have at the tv station is quite small, pack of cigs size,
> and its sliding lid is interlocked so well I've never seen the lamp
> lit.
>
>> The one I have is marked "G8T5...".
>>
>> That is : "G8T5" followed by three dots (...) and a warning to avoid
>> the rays.
>>
>> It may be listed under "Germicidal" in the lamp catalogs.
>
> That one should be a quartz tubed lamp, most of the germicidals were.
> I have NDI how long it will take it to wipe a 2764 though.  It takes
> more than the minimum to get all $FF's out of it, but it can be
> overdone according to my reading on that quite a few years ago now.
> The effect is that eventually it won't program regardless of how many
> write pulses you bang it with.

I am having a problem understanding your comments.

Are you saying that the G8T5... will not erase EPROMS?

It is a very large number of years since I used it but I do not remember any
problems.


>> Stephen H. Fischer
>>
>> Roger Taylor wrote:
>>> I'm looking for a used EPROM eraser, doesn't matter how old or ugly
>>> it is, as long as it works.  Also a 21v power supply if somebody can
>>> dig one of those out of your parts stash.  Bare wires at the end is
>>> ok because I will be soldering it to a 2-hole header for plugging
>>> into the Disto EPROM programmer.
>>>
>>> If you donate it towards the CoCo3.com efforts to create new
>>> products, I will return a Portal-9 or Rainbow IDE registration, or
>>> if you want cash let me know your asking price.
>>>
>>> I also want to ask other developers what the most common or popular
>>> Windows-based EPROM programmer might be so I can start looking into
>>> adding support to my IDEs.  I definatetly want to let the users burn
>>> their software to ROM right from the IDE if they are creating those
>>> kinds of images.
>
> Figure on spending about $800-$1000 or more for a windows/dos based
> solution in the one size fits all category.  The one I have at the tv
> station can be adjusted in the driver to burn virtually any of the
> eproms that were popular up to about 6-10 years ago.  But as I'd never
> bought the extra socket adaptor kits for the newer stuff, I haven't
> updated it in quite some time, 7 maybe 8 years now.  Its brand name was
> "Super"-something I've long since forgotten.  I bought it at the time
> to fix a problem in a video effects device that the maker wouldn't.
> And I did fix it...  And a couple of other things while I was at it.
> OTOH, the one I made, nearly 30 years ago now, I think I might have had
> a $30 bill in it.  The most expensive piece was the ZIF socket, which
> was about a tenner.
>
>>> --
>>> Roger Taylor

> --
> Cheers, Gene

You can convince many people that a simple task is one that requires huge
$$$$.

For the limited number of EPROM types that CoCo'ers would want to program
the parts cost is trivial.

Five dollars is too much I suspect even today if the very old parts have not
risen in price. Using today's parts, it may be a simple one chip solution
(PIC).

While I have not constructed (As far as I remember) the simple programmer
that I determined would be all that is necessary and I have not written the
software I can supply the basis of that conclusion (A more parts intensive
burner that I have and used several times for the SYM-1). Both the hardware
and software needed is very simple once you understand the simple task. The
CoCo is better for the task than a PC and if I remember correctly, I planned
to write the software in BASIC.

-- 
Stephen H. Fischer