Today I bought an A540 and an R260.
Where?You don't need any battery fitted on any Acorn machine for it to start up.I first removed the battery from both and then cleaned the area as usual with vinegar and isopropanol.
Now I wanted to carry out a function test on both, but unfortunately I can't get any further.
The keys light up briefly but there is no picture, a Benq712 is connected which should actually harmonise well with both.
My question would now be is a built-in battery mandatory for these computers or should a picture appear by switching on R or Del.
The "keys lighting up" is actually irrelevant - that's just what the keyboard does when it gets power, all by itself (it's just a separate microcontroller on a serial port).
As you may have gathered from this forum, A540/R260 are notorious for being damaged by battery leak. There are lot of very critical tracks right next to the battery. And they've very fine. Battery goo leaks under the IOC chip which is right next to it which kills even the most basic start-up functions. It can take a lot of work to even repair a machine far enough to even start POST, nevermind get a complete POST.
I can't easily tell from your photos what's leak, and what's just dust/dirt on the board. I would NEVER recommend fully submerging boards for cleaning, but carefully cleaning a much wider area of the board around the battery would allow some better assessment of the situation.
Download the A540 service manual. Follow the troubleshooting guide section 5, starting on page 95 (5-23) - "Repairing a 'dead' computer" - it will guide you through a good list of tests, checking for clocks and activity.
Could I also ask a favour - could you check the label on IC71? Is it a "-2" ?
Statistics: Posted by IanJeffray — Sat Jan 25, 2025 11:15 pm