Hybrid 2068/spectrum 48k rom mod
6 messages · 2014-01-27 → 2014-03-31 · Yahoo Group era · View archive on archive.org
Participants: quantam2001, Mark Martin, Brian Green, Chris Raynak, kmitl22
Preserved from the Timex/Sinclair 2068 Yahoo Group (2001–2019), which is no longer online. Text reproduced from the archive.org archive; email addresses masked.
Messages
1. Hybrid 2068/spectrum 48k rom mod
quantam2001 · 27 Jan 2014 17:03:18 -
So how many have tried Richard's Eprom mod? The reason I ask is I just completed the last step of the process by installing the new EPROMs and it works great! However when I first considered doing the modifications I realized that I had no way to create the EPROMs necessary, like Richard did, since I do not have an eprom programmer. That sent me looking for options. Well I found a small company that will burn and ship both chips for a very reasonable price using Richards rom images! I know that I am way behind (some 30 years) on this subject, but just in case anyone is interested, I can post the additional details.
2. Re: [ts2068] Hybrid 2068/spectrum 48k rom mod
Mark Martin · Tue, 28 Jan 2014 08:16
Please do share. I may never get my burner working.
On Jan 27, 2014 8:16 PM, <[email]> wrote:
>
>
> So how many have tried Richard's Eprom mod? The reason I ask is I just
> completed the last step of the process by installing the new EPROMs and it
> works great! However when I first considered doing the modifications I
> realized that I had no way to create the EPROMs necessary, like Richard
> did, since I do not have an eprom programmer. That sent me looking for
> options. Well I found a small company that will burn and ship both chips
> for a very reasonable price using Richards rom images! I know that I am way
> behind (some 30 years) on this subject, but just in case anyone is
> interested, I can post the additional details.
>
>
3. Re: [ts2068] Hybrid 2068/spectrum 48k rom mod
Brian Green · Tue, 28 Jan 2014 20:50
I've tried it, works fine though I haven't loaded up anything yet ;) I was
happy that it just fired up.
I'm curious where you're getting the chips made? I burnt mine using an old
Promenade C1 Eprom programmer on my C64.
On Mon, Jan 27, 2014 at 7:03 PM, <[email]> wrote:
>
>
> So how many have tried Richard's Eprom mod? The reason I ask is I just
> completed the last step of the process by installing the new EPROMs and it
> works great! However when I first considered doing the modifications I
> realized that I had no way to create the EPROMs necessary, like Richard
> did, since I do not have an eprom programmer. That sent me looking for
> options. Well I found a small company that will burn and ship both chips
> for a very reasonable price using Richards rom images! I know that I am way
> behind (some 30 years) on this subject, but just in case anyone is
> interested, I can post the additional details.
>
>
4. Re: [ts2068] Hybrid 2068/spectrum 48k rom mod
Chris Raynak · Wed, 29 Jan 2014 07:06
To get a set of Eproms I discovered www.EpromPRO.com.
They custom burn Eproms in small or large quantities. The process I used was simple.
First, I downloaded the rom images from Richard's blog.
Second, I took a detailed look at Richard's notes and photos, noting not only the chip numbers he referenced, but also the exact make, model and speed of the Eproms he used. I wanted to follow what he did as closely as possible.
Third, I sent an email to EpromPRO. Their requirement for determining pricing is pretty simple.
You email them the following:
1) The make and model of the EPROMs you want.
2) How many chips you need.
3) Your mailing address.
4) You attach the ROM image files to your email.
They get back to you (usually within 24 hours) detailing out your price. I was able to obtain both chips for around $25 shipped to the U.S. (They are located in Canada). Within ten days I had the chips in hand. They arrived in a bubble mailer very well packed, enclosed in a static bag. Each was labeled very nicely!
The specifics of what exactly I specified to them was as follows:The first chip is: AM27C128-155DC (an AMD 128k eprom)
The second chip is: AM27C256-150DC (an AMD 256k eprom)
I have subsequently contacted EpromPRO about how well the chips worked, and the owner (Stephan) said that he may put up a special page up for these Eprom's for the Timex Sinclair. So you might even find a page for it eventually.
While following Richard's blog, I found myself reworking his photos, because for me, they were a little hard to follow. He does cover exactly what needs to be done, but I found myself having to inspect them very carefully to pick up on the details of what he did. I also altered slightly the method of switching between the two Eproms. Rather than use his method of utilizing the channel 2/3 video switch, I simply installed a 3 position mini switch. For me, I thought it would be sort of a hassle having to lift up the computer every time I wanted to switch between the two Eproms, especially once you attach components on the back of the bus. There is absolutely nothing wrong with the way Richard did his mod, and it does preserve the "look" of the TS2068. I just found a different switch easier for me.
If there is enough interest, I can produce a simple "how to" rework for this mod, using the reworked photos and some of the simple test tips I used for making sure things are done right, each step of the way.
5. RE: Hybrid 2068/spectrum 48k rom mod
quantam2001 · 29 Jan 2014 12:14:48 -
To get a set of Eproms I discovered www.EpromPRO.com.
They custom burn Eproms in small or large quantities. The process I used was simple.
First, I downloaded the rom images from Richard's blog.
Second, I took a detailed look at Richard's notes and photos, noting not only the chip numbers he referenced, but also the exact make, model and speed of the Eproms he used. I wanted to follow what he did as closely as possible.
Third, I sent an email to EpromPRO. Their requirement for determining pricing is pretty simple.
You email them the following:
1) The make and model of the EPROMs you want.
2) How many chips you need.
3) Your mailing address.
4) You attach the ROM image files to your email.
They get back to you (usually within 24 hours) detailing out your price. I was able to obtain both chips for around $25 shipped to the U.S. (They are located in Canada). Within ten days I had the chips in hand. They arrived in a bubble mailer very well packed, enclosed in a static bag. Each was labeled very nicely!
The specifics of what exactly I specified to them was as follows:
The first chip is: AM27C128-155DC (an AMD 128k eprom)
The second chip is: AM27C256-150DC (an AMD 256k eprom)
I have subsequently contacted EpromPRO about how well the chips worked, and the owner (Stephan) said that he may put up a special page up for these Eprom's for the Timex Sinclair. So you might even find a page for it eventually.
While following Richard's blog, I found myself reworking his photos, because for me, they were a little hard to follow. He does cover exactly what needs to be done, but I found myself having to inspect them very carefully to pick up on the details of what he did. I also altered slightly the method of switching between the two Eproms. Rather than use his method of utilizing the channel 2/3 video switch, I simply installed a 3 position mini switch. For me, I thought it would be sort of a hassle having to lift up the computer every time I wanted to switch between the two Eproms, especially once you attach components on the back of the bus. There is absolutely nothing wrong with the way Richard did his mod, and it does preserve the "look" of the TS2068. I just found a different switch easier for me.
If there is enough interest, I can produce a simple "how to" rework for this mod, using the reworked photos and some of the simple test tips I used for making sure things are done right, each step of the way.
6. RE: Hybrid 2068/spectrum 48k rom mod
kmitl22 · 30 Mar 2014 23:30:51 -
Hi,
I did the modification without cut any track on PCB. I didn't utilize the channel 2/3 switch either.
For EX ROM, use a small wire to short pin 1 and pin 28, don't connect pin 27 into its socket, bend it up and connect to middle pin of switch.
For HOME ROM, pin1, 27, 28 do the same as EX ROM. don't connect pin 22 into its socket, bend it up and solder a small hard wire to it and the other side of wire put into pin 27 of socket.
http://tinypic.com/r/muhkd3/8 http://tinypic.com/r/muhkd3/8
http://tinypic.com/r/245h9pt/8 http://tinypic.com/r/245h9pt/8
If you have twister board, you can use DivMMC with this internal modification.
Don
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TS2068 / TC2068 · ZX Spectrum · Cartridges, EPROM & dumping · Hardware projects & new boards