Haven't done any pcb etching for 30 years, lovely messy job if I remember right,
would sending the design off to a one off local manufacturer not be an easier route?
I think it works out cheaper than buying a pcb home etch kit.
I've recently knocked up a kempston joystick/ear amplifier combo thingymabob circuit for my spectrum (combination of other peoples work)
using designspark and veecad and put on proto board was tempted to send off for a pcb worked out about 20 quid,
Thoroughly enjoyed doing that been a long time since I've done anything like it.
Would you be able to use a breadboard to test the design or would that mess with timings etc
Bright White screen .No cursor
Re: Bright White screen .No cursor
I have a working ZX81, and a non working ZX81, so this project hasn't been 1st priority.
It was the purpose of this project for me to make the pcb myself. It won't be messy as I won't use ferrochlorid but simply lemon juice, salt and hydrogen peroxide.
It was the purpose of this project for me to make the pcb myself. It won't be messy as I won't use ferrochlorid but simply lemon juice, salt and hydrogen peroxide.
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povvercrazy
- Posts: 28
- Joined: Sun Apr 09, 2017 9:11 pm
Re: Bright White screen .No cursor
Quick update, 16k RAM pack is fixed followed a guide on here to check systematically for faults, all voltages were ok, so I socketed all the ram chips,
replaced all the caps, checked transistor, re-flowed all the solder joints... nothing
Checked continuity on the ribbon cable, seemed ok but was a bit brittle so replaced that.
Luckily the lower 16k in my spectrum was socketed and I just got Retroleums Smart Interface so did a chip swap and tested the 4116's
in my spectrum they were all ok, so put them back in the ram pack and plugged it in to test...it works fine!!!
I cant remember if I tested the ram pack after I replaced cable or it was magic elfs but I know have a working Issue 1 81 with a sinclair 16k ram pack!
Now just to wait for the post to bring me the composite/backporch mod from Pokemon
replaced all the caps, checked transistor, re-flowed all the solder joints... nothing
Checked continuity on the ribbon cable, seemed ok but was a bit brittle so replaced that.
Luckily the lower 16k in my spectrum was socketed and I just got Retroleums Smart Interface so did a chip swap and tested the 4116's
in my spectrum they were all ok, so put them back in the ram pack and plugged it in to test...it works fine!!!
I cant remember if I tested the ram pack after I replaced cable or it was magic elfs but I know have a working Issue 1 81 with a sinclair 16k ram pack!
Now just to wait for the post to bring me the composite/backporch mod from Pokemon
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povvercrazy
- Posts: 28
- Joined: Sun Apr 09, 2017 9:11 pm
Re: Bright White screen .No cursor
DahDah
forgive the mess, just installed Pokemons ZX81 backporch mod board which arrived this morning,
Have left the modulator in place just disconnected it hence the trailing composite lead.
At first I thought I'd messed up as screen was still black, so increase the brightness on TV and the cursor was now an exclamation mark! errr
So I looked at Pokemons instructions and thought I'd tune it in and voila, nice bright white background and clear sharp pixels.