Search found 114 matches

by bola_dor
Thu May 28, 2020 5:58 pm
Forum: Hardware
Topic: PSU and regulators
Replies: 1
Views: 28

PSU and regulators

Hi. Would it be advisable to use an external LM7807 or LM7808 to feed the internal LM7805 jut to avoid the extra heating inside the case? I know that some rampacks need the 9v line but I am planning to use a 4164 modified rampack or a custom made SRAM one.. My min xon er is about a ZX80 .. I have tw...
by bola_dor
Wed May 27, 2020 2:01 pm
Forum: Hardware
Topic: TS2068 video output mod?
Replies: 5
Views: 89

Re: TS2068 video output mod?

1024MAK wrote:
Wed May 27, 2020 10:14 am
Maybe the colour encoder circuit has a problem, for example the crystal frequency has drifted badly.

You may have more luck if you post on World of Spectrum forums ;)

Mark
thank you !! I'll check crystal and go to work..
by bola_dor
Wed May 27, 2020 2:00 pm
Forum: Hardware
Topic: TS2068 video output mod?
Replies: 5
Views: 89

Re: TS2068 video output mod?

I think your TS2068 provides good colours for NTSC standard. Do not expect anything similar to PAL, in NTSC all colours are washed out. There a solution, a mini board with PAL encoder like AD724 that could be connected to the edge connector. R, G, B & video signals are available there. When using a...
by bola_dor
Wed May 27, 2020 4:50 am
Forum: Hardware
Topic: TS2068 video output mod?
Replies: 5
Views: 89

TS2068 video output mod?

Hi, I know this is a mainly Sinclair forum but I just Got this TS 2068 to discover how Ugly its video output is. It has an RF modulated output and a "monitor" composite output.. This is an NTSC computer but is not a problem as all my LCD TV support both PAL and NTSC.. but colours are not OK.. it loo...
by bola_dor
Fri May 22, 2020 2:56 am
Forum: Hardware
Topic: Back Porch circuit and a back porch generating ULA
Replies: 2
Views: 135

Back Porch circuit and a back porch generating ULA

Hi, I've built the 555 based circuit By Ziggurat http://zx.zigg.net/misc-projects/ I plan to use it on a ZX80 but meanwhile tested it with my CZ1000.. with a Ferranti 2C210E ULA which grates an appropriate back porch. 20200521_211818.jpg What I've noticed is a really crisp, steady and noiseless K cu...
by bola_dor
Thu May 21, 2020 10:14 pm
Forum: Hardware
Topic: ZX80 US vs UK..
Replies: 5
Views: 228

Re: ZX80 US vs UK..

Also read this topic ;) Mark Thanks.. I am about to receive one ZX80 US soon so I am quite anxious :D I've already made my own video back porch composite mod from http://zx.zigg.net/misc-projects/ while waiting.. (Should this be moved to the hardware forum?) Are there any known software incompatibi...
by bola_dor
Thu May 21, 2020 9:08 pm
Forum: Hardware
Topic: ZX80 US vs UK..
Replies: 5
Views: 228

Re: ZX80 US vs UK..

What would be the differences between the ZX80 US vs UK versions? Do both have ISS 1 and 2? Having owned both US and UK types the only difference I could detect was the television standard between the two countries ie the modulator. Mine was a later ABS cased model suggesting issue 2 as per my UK o...
by bola_dor
Thu May 21, 2020 7:48 pm
Forum: Hardware
Topic: ZX80 US vs UK..
Replies: 5
Views: 228

ZX80 US vs UK..

What would be the differences between the ZX80 US vs UK versions? Do both have ISS 1 and 2?
by bola_dor
Sun May 17, 2020 2:30 am
Forum: Hardware
Topic: TS1000 with no image :_(
Replies: 62
Views: 3604

Re: TS1000 with no image :_(

Please confirm that the Z80 has power. Test between any 0V/GND point and pin 11 on the Z80. Test from any +5V point and pin 29 on the Z80. On the Z80, test the actual pins of the chip. Done If you still have access to a ‘scope, and it is a dual channel type, use one channel to monitor pin 26 on the...
by bola_dor
Sun May 17, 2020 1:58 am
Forum: Hardware
Topic: TS1000 with no image :_(
Replies: 62
Views: 3604

Re: TS1000 with no image :_(

Hang on a minute! That photo of the ‘scope screen showing the clock on pin 6 is showing a 6.4MHz signal :shock: . The NMOS Z80 is only rated for a maximum of 4MHz and in a ZX81/TS1000 should be 3.25MHz. Are you using a modern ULA module rather than an original Ferranti ULA? The waveform on ULA pin ...