ZX Spectrums problems : diagnostic software ?

dizzy33
Posts: 53
Joined: Mon Jan 13, 2020 3:24 pm

Re: ZX Spectrums problems : diagnostic software ?

Post by dizzy33 » Thu Mar 26, 2020 12:29 pm

No, where should it be ? On my Spectrum issue 2 motherboard ?

User avatar
1024MAK
Posts: 2763
Joined: Mon Sep 26, 2011 10:56 am
Location: Looking forward to summer in Somerset, UK...

Re: ZX Spectrums problems : diagnostic software ?

Post by 1024MAK » Thu Mar 26, 2020 12:39 pm

No, but if you have one, when some other components are added, it can be used for some testing.

Mark

User avatar
Paul
Posts: 1073
Joined: Thu May 27, 2010 8:15 am
Location: Germanys west end

Re: ZX Spectrums problems : diagnostic software ?

Post by Paul » Thu Mar 26, 2020 1:33 pm

dizzy33 wrote:
Thu Mar 26, 2020 12:15 pm
Thanks a lot for your quick answer, I will check that.
EDIT : AAaargh ! it's much more expensive ... As I do not know if I'll be able to use it in other cases than for the Spectrum ... I need to think about it ...
The MongKok DSO168 is in a similar price range as yours,
but its not availabe via amazon prime, just normal.
In theory, there is no difference between theory and practice. But, in practice, there is.

dizzy33
Posts: 53
Joined: Mon Jan 13, 2020 3:24 pm

Re: ZX Spectrums problems : diagnostic software ?

Post by dizzy33 » Thu Mar 26, 2020 2:11 pm

Thanks a lot, but as you said it's not Prime. So I'll guess I will go for the one shown by Mark :
https://www.amazon.fr/gp/product/B07WV1 ... I80K&psc=1
But this is quite expensive for me (around 100€), so before buying I need to be sure of a few things, this will depend on the answers from Mark.
Mark, can you please answer to these questions ?
- with this model, will you be able to tell me how to use it (but of course I will try myself, reading the documentation) ?
- will you be able to guide me on how to proceed to test different components of my issue 2 motherboard ?
- with this oscillator specs, do you think I will be able to test also 16 bits computers like the Atari ST ?
The official specs are 100 Mhz and 500 mega samples / secs, but in reality, according to what I could see on youtube, it's more 40Mhz (don't know the real number the mega samples)

User avatar
1024MAK
Posts: 2763
Joined: Mon Sep 26, 2011 10:56 am
Location: Looking forward to summer in Somerset, UK...

Re: ZX Spectrums problems : diagnostic software ?

Post by 1024MAK » Thu Mar 26, 2020 3:08 pm

For most 8 bit computers normally an analogue bandwidth of 20 MHz to 25 MHz is the minimum recommended.
For the remaining 8 bit and most 16/32 computers (including Atari ST/STFM/STE machines), an analogue bandwidth of 40 MHz is the minimum recommended.

That is an unusually low price for the specs that they are claiming.

I can describe the general usage of an oscilloscope, but you will need to be able to make sense of the manual / instructions to work out how to use the features of this particular item of test gear.

If you want something cheaper, go for a ready made logic probe or a logic analyser. Both can tell you if a digital signal is a logic low or a logic high.

A logic probe can display the state of the signal (logic low, logic high or no indication if it’s not a valid logic level). Some have a pulse detector and some have a sounder so you can hear a different tone depending on the state of the input signal.

A logic analyser is used with a computer and can show you the signal transitions that it has recorded. So you can see over a time period what signal transitions took place.

An oscilloscope is much more expensive because it has to deal with analogue signals and this is MUCH more complex. With a digital ‘scope, that means expensive fast and accurate analogue to digital converter circuitry.

I hope this helps ;)

Mark

dizzy33
Posts: 53
Joined: Mon Jan 13, 2020 3:24 pm

Re: ZX Spectrums problems : diagnostic software ?

Post by dizzy33 » Thu Mar 26, 2020 3:35 pm

Thanks a lot Mark, I'll buy the one you recommanded. I will train myself with it and then I will ask you what to test on the issue 2 motherboard.
Thanks again for your information and your time (here in France we have plenty of time as we are stucked at home, is it the same for you ? Do you live in England ?).

User avatar
1024MAK
Posts: 2763
Joined: Mon Sep 26, 2011 10:56 am
Location: Looking forward to summer in Somerset, UK...

Re: ZX Spectrums problems : diagnostic software ?

Post by 1024MAK » Thu Mar 26, 2020 7:11 pm

dizzy33 wrote:
Thu Mar 26, 2020 3:35 pm
Thanks a lot Mark, I'll buy the one you recommanded.
Happy to help, but I think it was Paul that pointed to the ‘scope you are thinking of buying, not me.

Yes, I live in England, in fact in the South-West of the country.
I work for an infrastructure company and am classed as a critical / key worker. The work that I do requires me to be physically present, so no home working or staying at home for me.

I’m not at work at the moment because I worked last weekend, so I have some days off during the week instead. This would have happened regardless of the current COVID19 Corona Virus restrictions.

The U.K. is in lockdown like many other countries. All social gatherings are banned. Today the police have gained new powers to deal with anyone who does not have a very good reason to be out of their home. The new powers include new fines and dispersing gatherings. Repeat offenders may face prison.

The government has told the population, work from home where you can. Key workers (and the children of key workers going to school) are the only people who should be traveling by public transport.
  • People in the U.K. will be allowed to leave their homes for only “very limited purposes” - shopping for basic necessities; for one form of exercise a day; for any medical need; and to travel to and from work when “absolutely necessary”
  • People are warned not to meet friends or family members who they do not live with
  • Shopping is only permitted for essentials like food and medicine, and people are advised to do it “as little as you can”
  • All shops selling non-essential goods, such as clothing and electronic stores, are ordered to close
  • Libraries, playgrounds, gyms and places of worship are closed
  • Restaurants, public houses and any other entertainment venues are closed
  • All gatherings of more than two people in public - excluding people you live with - are banned
  • All social events, including weddings and baptisms are banned
  • Schools, nurseries, colleges and universities are closed, but some schools will allow the children of key workers to continue to attend, so that those key workers can continue to go to work.
Mark

Aurelbois
Posts: 6
Joined: Wed Jul 10, 2019 7:36 pm

Re: ZX Spectrums problems : diagnostic software ?

Post by Aurelbois » Thu Mar 26, 2020 9:44 pm

This the very same for Canada. I live near Toronto, Ontario Canada.
It is difficult to have to stay home as we are over 70 of age.
Fortunately we have a son that can help when needed that live close by.
Stay safe and in good health.

dizzy33
Posts: 53
Joined: Mon Jan 13, 2020 3:24 pm

Re: ZX Spectrums problems : diagnostic software ?

Post by dizzy33 » Thu Mar 26, 2020 11:44 pm

Here in France I also work with infrastructures as I work for a storage company. I maintain storage machines so I also need to work out of my home, and unfortunatly I mostly work on customers sites, and I may need to drive for 7 hours in one day just for one customer (my customers may be very far from home).
So it's very risky regarding the virus, but as these infrastructures are important for the biggest companies of the country (hospitals, etc ...), I do it not only to keep my job, but also because I must participate to this "war".

Now just to stay in this thread subject, even if my Spectrum is not yet fixed, I thank all of you for your answers.

dizzy33
Posts: 53
Joined: Mon Jan 13, 2020 3:24 pm

Re: ZX Spectrums problems : diagnostic software ?

Post by dizzy33 » Fri Apr 03, 2020 1:03 pm

Hello Mark, I just received my oscilloscope. Can you please tell me what should I test with it ? (please tell me on which pin I should put the probes as I am totally noob ...). Reminder : this is an issue 2 board having some random RAM problems after 1 minute of use, all RAM are OK, but the RAM test cartridge shows some RAM as defective, and never the same one (all RAM chips, Z80, ULA, TR4/TR5 have been replaced, full recap done).
Thanks !

Post Reply