Problem at start-up

[Mike Holder]

Hello and greetings from Finland.

I recently got a hold of a Sinclair QL that unfortunatelly seems to have some issues starting up Not being familiar with the QL (used to have a Speccy in the 80s) I am not 100% sure how the normal QL start-up should look like. I am expecting to see the start-up screen with F1/F2 monitor type selection eventually, but what I get is around 5-6 seconds of red/green/black/white dot pattern (memory test?) and then just a blank white screen afterwards (I also tried just pressing F1/F2 at this point anyway with no effect).

I googled this issue a bit and found some suggestions to remove/replace the 8301 chip and see if that would help, but once I opened up the QL to do that I found out that this particular device had its memory upgraded at some point by piggy-backing RAM chips on top of the original ones. The RAM upgrade looks quite failure prone due to all the extra bits of wiring, but since the device locks-up at the blank white screen, is it the 8301 chip that´s the most likely culprit?

Any ideas of how to proceed in order to resurrect this QL would be appreciated.

Thanks in advance.

[M68008]

Take a look at the QL Service Manual (for example there is a link to the PDF on this page: http://www.worldofspectrum.org/documentation.html), section 2.2 explains how to diagnose startup issues. The ZX8301 (or most of it anyways ) is likely working if you correctly see the inititial dot pattern. According to the Service Manual, "To summarise, if on power up a white or green screen is displayed, it indicates that the RAMs are in general working, and that the machine
is very close to being fully operational. It suggests a data or address line short-circuit or a faulty RAM chip".

[RWAP]

My first step would be to remove the internal memory upgrade - these were slower than the external memory upgrades in any case, and it is probably one of these memory chips which has failed.

[Mr_Navigator]

Failing everything else you could bring the QL along to one of the Quanta sub-group meetings too see if someone could help you. Obviously it would help to be a Quanta member (for a small annual subscription and six bi-monthly magazines)
http://www.quanta.org.uk

[Mike Holder]

Take a look at the QL Service Manual (for example there is a link to the PDF on this page: http://www.worldofspectrum.org/documentation.html), section 2.2 explains how to diagnose startup issues. The ZX8301 (or most of it anyways ) is likely working if you correctly see the inititial dot pattern. According to the Service Manual, "To summarise, if on power up a white or green screen is displayed, it indicates that the RAMs are in general working, and that the machine
is very close to being fully operational. It suggests a data or address line short-circuit or a faulty RAM chip".

My first step would be to remove the internal memory upgrade - these were slower than the external memory upgrades in any case, and it is probably one of these memory chips which has failed.

Thanks for the tips.

I think that I´ll just go ahead and attempt the removal of the memory upgrade in order to revive this QL. It would actually be nicer to have a robust QL to play with than have some more unstable one with extra RAM

http://www.flickr.com/photos/9020837@N0 ... otostream/
http://www.flickr.com/photos/9020837@N0 ... otostream/

Failing everything else you could bring the QL along to one of the Quanta sub-group meetings too see if someone could help you. Obviously it would help to be a Quanta member (for a small annual subscription and six bi-monthly magazines)
http://www.quanta.org.uk

Thanks for the idea Unfortunatelly, I´m a bit far away to attend (Finland).

[Mr_Navigator]

Hmmn I wonder if there are any QL support groups in Finland?

I will see what I can find out

[RWAP]

I don't think there are any user groups in Finland - and I only have 4 QL users on my customer list from Finland.

I do think that it will be a steep curve to remove that memory upgrade, as all of the chips have been piggy backed - it is a lot of de-soldering.

It might just be easier to get another QL motherboard - I have several here which need testing!

[Mike Holder]

I do think that it will be a steep curve to remove that memory upgrade, as all of the chips have been piggy backed - it is a lot of de-soldering.

It might just be easier to get another QL motherboard - I have several here which need testing!

I´ve sent you an e-mail inquiring about those QL motherboards.

In the mean while, I did not actually even manage to attempt de-soldering those piggy backed memory chips. The mains fuse of my soldering station seemed to have blown...

[ppe]

In the mean while, I did not actually even manage to attempt de-soldering those piggy backed memory chips. The mains fuse of my soldering station seemed to have blown...

If you live near Espoo I can lend you my soldering iron

Looks like removing those chips would be a lot of work... Probably your best bet at resurrecting the machine, though.

[Dave]

That's an impressive level of work to go to to put in an upgrade.

Some very fine pointed snips would allow you to cut the upper chip pins and remove them, plus the wiring. You may just decide to obtain 16 new RAM ICs from a dead board and remove/replace everything - if you're careful about pulling up tracks it is very doable.

Failing that, if you leave the ICs in place and simply remove all the additional wiring, The ICs will not have access to extra address lines and will simply echo the original ICs. Cutting only the power +5v pins will take away their heat and current draw too.