Search found 54 matches

by zx81user
Fri May 03, 2013 11:58 am
Forum: Hardware
Topic: 16K RAM Pack Schematic / Chip Layout
Replies: 71
Views: 28715

Re: 16K RAM Pack Schematic / Chip Layout

Nice work, just be careful not to flex that wire bridge too much, they are quite easy to break, you better treat them with same care as the keyboard flex cable..... I had some luck a few weeks back with a pack that had a faulty transistor, so I would check that first. If you exchange RAM chips and d...
by zx81user
Fri May 03, 2013 2:16 am
Forum: Sinclair Misc
Topic: Spectrum + Assessment ? NEW
Replies: 30
Views: 5932

Re: Spectrum + Assessment ? NEW

5% based on $2000 sale price is really much. In Germany transaction fees on eBay are based on the value / final price. I think for expensive items it is about 3% maximum. But now I took a look and it has increased significantly to 9% ! :o Okay they have a maximum of 75 EUR resp. 50 USD but it is re...
by zx81user
Thu May 02, 2013 7:54 am
Forum: Sinclair Misc
Topic: Spectrum + Assessment ? NEW
Replies: 30
Views: 5932

Re: Spectrum + Assessment ? NEW

If Paypal take high fees (they do !) and if they want to protect buyers they sould pay these bills on their own. Agreed, the fees are really high. I sold something not that long ago for about $2,000 that was paid through paypal, I later found a $100 ebay fee AND a $100 paypal fee or thereabouts!! T...
by zx81user
Thu May 02, 2013 7:01 am
Forum: Development
Topic: ZX81XRAM - external 32k memory module +HRG
Replies: 7
Views: 2962

Re: ZX81XRAM - external 32k memory module +HRG

PokeMon wrote:It shouldn't be enabled during ROM disabling at startup when reading address 4 and let the pullup resistors deliver $FF instead of $7F.
That is a tricky one indeed!

Michel
by zx81user
Wed May 01, 2013 12:41 pm
Forum: Sinclair Misc
Topic: Spectrum + Assessment ? NEW
Replies: 30
Views: 5932

Re: Spectrum + Assessment ? NEW

no i think that collectors always telling you lower price because someone like them can buy it on that forum for lower price , i try to ask on 3-4 forums sega, nintendo , spectrum, commodore always get low price from users , but when they selling they wish not to drop price for 5$ :))) so after i s...
by zx81user
Wed May 01, 2013 11:35 am
Forum: SALES
Topic: ZX81CCP
Replies: 104
Views: 36336

Re: ZX81CCP

PokeMon wrote:No you overread. I am not planning to develop a ZX81 board. That's your mistake. ;)
Oh yes, I see now! :oops:
by zx81user
Tue Apr 30, 2013 11:19 pm
Forum: SALES
Topic: ZX81CCP
Replies: 104
Views: 36336

Re: ZX81CCP

Maybe you overread this - I am not working on a redesign of a ZX81, it is for the ZX80 which doesn't have an NMI generator. By the way, I do add on's very moderate. There are many discussions what a ZX80 or ZX81 is and what's elementary. For the example speed, this is unwanted when you play games a...
by zx81user
Mon Apr 29, 2013 11:43 pm
Forum: SALES
Topic: ZX81CCP
Replies: 104
Views: 36336

Re: ZX81CCP

How much would such an interface cost? Michel Thanks for your thoughts. I can not say how much such an interface would cost exactly, my idea is not more than maybe 20 or max 30 EUR. Something like that. It's my summer project with no stress at all. In the moment I work an the ZX81XRAM (finished tod...
by zx81user
Mon Apr 29, 2013 8:29 am
Forum: SALES
Topic: ZX81CCP
Replies: 104
Views: 36336

Re: ZX81CCP

[quote="PokeMon"And plan a new luxury version which keeps the picture content - not just an empty synced screen. That would be fun and that would be a nice add on for all ZX80 around to have a stable picture during running program. :o[/quote] Hi PokeMon, You seem really into this ZX81 video thing an...
by zx81user
Sun Apr 28, 2013 12:15 am
Forum: Hardware
Topic: Simple Video Mod for 210ULA
Replies: 19
Views: 8332

Re: Simple Video Mod for 210ULA

Correction to an earlier post where I said that the modulators RF out is coupled through a small value capacitor and was possible to feed composite out without removing/disconnecting the modulators innards ... not quite so - I was going on information from another source - not tried by myself until...