spectrum 128 no display

Post Reply
jojo
Posts: 129
Joined: Mon Mar 16, 2020 5:25 pm

spectrum 128 no display

Post by jojo »

spectrum 128 no display on TV and RGB output ;

i have verified and swapped the ;

ula
rom

no change ,

12v is around 11,5v

no component is heavily heating up .

suspect tea2000 ?

any help appreciated
Zx81-16k exp.- Spectrum 48 - Spectrum 128- Interface 1 - DIVide - Zx flashcard- Zx printer - Ram turbo-Velleman interface system-Currah microspeech -Ql - 512k exp.- Ql printer - Cst floppy interf.- Double 3.5 floppy- Minerva - Qimi-and much more .
User avatar
1024MAK
Posts: 5101
Joined: Mon Sep 26, 2011 10:56 am
Location: Looking forward to summer in Somerset, UK...

Re: spectrum 128 no display

Post by 1024MAK »

A faulty TEA2000 should not affect the RGB output…

Is the Z80A getting a 3.5MHz clock on pin 6?

Mark
ZX81 Variations
ZX81 Chip Pin-outs
ZX81 Video Transistor Buffer Amp

:!: Standby alert :!:
There are four lights!
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb :!:
Looking forward to summer later in the year.
jojo
Posts: 129
Joined: Mon Mar 16, 2020 5:25 pm

Re: spectrum 128 no display

Post by jojo »

christmas eve overhere ,
i will see if i can get the test equipment next to the tree ;-)

tae2000 indeed receives the rgb from the ula , so no rgb in means no video out .
already swapped the ula , and no difference .

next search for the clock signals .

owner claimed it was working when he brought it to me ( with a tape-loader problem ) .

got one tape-loader problem solved in the typical way of re-soldering the socket to the pcb again .
now for the sudden death which has no video output and a tapeloader problem and a defective keyboard .
Zx81-16k exp.- Spectrum 48 - Spectrum 128- Interface 1 - DIVide - Zx flashcard- Zx printer - Ram turbo-Velleman interface system-Currah microspeech -Ql - 512k exp.- Ql printer - Cst floppy interf.- Double 3.5 floppy- Minerva - Qimi-and much more .
Post Reply