ZX Spectrum 128k+ faults - UK Vintage Radio Repair and Restoration Discussion Forum

Leejwood · 29th Aug 2016, 9:58 pm

Hi there all,

I need help, my Spectrum has a tape loader attached and the following happened to me

First the sound stopped as in everything, the tape loader sound stopped and any sound produced from spectrum stopped.

So then when turning off speccy and on again I not only had to retune the TV to show my speccy but found sound still not be heard and the tape loader completely stopped running , in other words when pressing play on tape loader to load anything the tape machine will not go , it's not doing anything like it's either frozen up or like no power getting to it. No wheels are turning so won't load anything , tape player is built in so has no wires and at the back of my speccy it has no in or out sockets to use another tape machine.

I have now been upset that I've lost all sound and tape machine is not working at all.

I have to say this bit to maybe be the reason all this has happened and that is when the picture on TV i.e. went out of tune showing untuned spectrum start menu I did slap my speccy a couple of times to see if that would cure the picture and then I turned everything off and on again an restarted from beginning tuning in TV etc etc as if I just got spectrum, this did cure picture and found sound still not working still and I tried loading game to see if I could hear loading sound from tape but then I found the tape machine not working

So the final question to all this:-

Why have my speccy stopped producing sound and why has my tape player stopped working.

I'm upset now and thought I'd ask here before I start to open up my speccy to inspect inside of it , I can do this as I am knowledgeable in electronics

But need everyone's advice first before I do look inside

Thanks if you can

TonyDuell · 30th Aug 2016, 6:22 am

I would start by checking all power supply voltages inside. Make sure they are correct, and (if you have one) use a 'scope to make sure they are free from ripple.

A machine will not run without power

Refugee · 30th Aug 2016, 9:44 am

Would it not be a snapped belt in the tape drive?

Mad Mal · 30th Aug 2016, 2:09 pm

That wouldn't affect the Sound from the Spectrum itself. As the later 128k+ machines were made by AMSTRAD I think it could be down to a problem with the custom ULA on the later models. Or the supply to the sound chip and modulator may have been affected. If the Tape deck is operating then the belt will be fine. Sins the ULA chip handled quite a lot of signal processing to I'd check it first. Point to note; Some of these 128K+ machines were made in Taiwan. The ULA chip on those was mounted in a socket. (like some earlier Amstrad 464 units had Chips in sockets) it could be down to socket creep.

29th Aug 2016, 9:58 pm	#1
Leejwood Retired Dormant Member Join Date: Aug 2016 Location: Bristol, UK. Posts: 1	ZX Spectrum 128k+ faults Hi there all, I need help, my Spectrum has a tape loader attached and the following happened to me First the sound stopped as in everything, the tape loader sound stopped and any sound produced from spectrum stopped. So then when turning off speccy and on again I not only had to retune the TV to show my speccy but found sound still not be heard and the tape loader completely stopped running , in other words when pressing play on tape loader to load anything the tape machine will not go , it's not doing anything like it's either frozen up or like no power getting to it. No wheels are turning so won't load anything , tape player is built in so has no wires and at the back of my speccy it has no in or out sockets to use another tape machine. I have now been upset that I've lost all sound and tape machine is not working at all. I have to say this bit to maybe be the reason all this has happened and that is when the picture on TV i.e. went out of tune showing untuned spectrum start menu I did slap my speccy a couple of times to see if that would cure the picture and then I turned everything off and on again an restarted from beginning tuning in TV etc etc as if I just got spectrum, this did cure picture and found sound still not working still and I tried loading game to see if I could hear loading sound from tape but then I found the tape machine not working So the final question to all this:- Why have my speccy stopped producing sound and why has my tape player stopped working. I'm upset now and thought I'd ask here before I start to open up my speccy to inspect inside of it , I can do this as I am knowledgeable in electronics But need everyone's advice first before I do look inside Thanks if you can

30th Aug 2016, 6:22 am	#2
TonyDuell Dekatron Join Date: Jun 2015 Location: Biggin Hill, London, UK. Posts: 5,208	Re: ZX Spectrum 128k+ faults I would start by checking all power supply voltages inside. Make sure they are correct, and (if you have one) use a 'scope to make sure they are free from ripple. A machine will not run without power

30th Aug 2016, 9:44 am	#3
Refugee Dekatron Join Date: Apr 2012 Location: Worksop, Nottinghamshire, UK. Posts: 5,553	Re: ZX Spectrum 128k+ faults Would it not be a snapped belt in the tape drive?

30th Aug 2016, 2:09 pm	#4
Mad Mal Tetrode Join Date: Jul 2016 Location: Spennymoor, County Durham, UK. Posts: 69	Re: ZX Spectrum 128k+ faults That wouldn't affect the Sound from the Spectrum itself. As the later 128k+ machines were made by AMSTRAD I think it could be down to a problem with the custom ULA on the later models. Or the supply to the sound chip and modulator may have been affected. If the Tape deck is operating then the belt will be fine. Sins the ULA chip handled quite a lot of signal processing to I'd check it first. Point to note; Some of these 128K+ machines were made in Taiwan. The ULA chip on those was mounted in a socket. (like some earlier Amstrad 464 units had Chips in sockets) it could be down to socket creep.