Replacement RAM chips for QL

[issue5]

Hi there, I am looking for replacement TMS4164A-15NL ram chips as I have just got another QL and it's faulty as the screen just displays a white screen - I did swap the JS ROMS for the excellent Minerva ROM from my other QL (kindly supplied by the always helpful chr$), and the RAM test revealed the faulty address - which the Minerva fault code RAM decoder tells me is IC7.

I am wondering if anyone on the forum is able to supply these chips (would perhaps like 4 or 5 to keep some as spares) or a compatible alternative, and could anyone recommend a good but not too expensive vacuum desoldering iron for this job. I've not replaced any chips like this before but I'm resolved to give it a go . And would you recommend fitting a socket rather than fitting the chip straight to the board?

I realise there's a few questions there but any help and advice would be much appreciated. Many thanks

[Pr0f]

Will answer the questions I can in no particular order:

Desoldering tool - I use an 80w / 24v station - it seems to be marketed by many different vendors - but is usually a cream coloured device with 3 pushbuttons on the front and a handgun shaped desoldering head. Suction is good, relatively easy to remove the glass solder catcher and clean it, and comes with various tips.

https://www.amazon.com/Digital-Desolder ... B07542D82F

Socket or direct replacement - really a matter of personal choice - if you were doing all the chips - then socket them, but for one - it's a personal preference.

For removal - it's sometimes easier to actually cut the legs of the faulty ic as close to the chip body as you can, then remove each pin with a soldering iron and tweezers - using the solder sucker to remove the solder - this will reduce the time you spend heating the pcb tracks and pads and will help to avoid damage to them.

I think I have a few chips - not sure on speed - could be 120 or 150ns and fairly sure they are not Texas Instruments.

[issue5]

Well thanks for your response, the soldering station you are talking about is exactly the one I have been looking at on reviews and seems to be a good option with some good reviews and less expensive than I thought. And I have found some used guaranteed identical chips on ebay at a fair price, so I think I'll get some chips, the desolderer and some sockets and give it a go - really appreciate your opinions and advice, that is really helpful. Thanks again