exxos's Atari, Amiga & retro forum

stephen_usher wrote: 31 Dec 2023 15:17 Thanks for the pointer about the watch. The traces are so thick that even after the corrosion there's still probably about 0.4mm of trace thickness! :-)

As for the Enterprise, yeah, I still have two of the orange disks (photon torpedoes) in the saucer. I got this in '76, so it's the same age as the watch. Apparently you can tell it's one made in the first year as the stickers on the nacelles are plastic rather than paper.

P.S. Looked at the vid. That was one of the expensive "Trafalgar" watches. This is a cheap "Boots" Hong Kong special with exposed gold wires an blobs on the silicon rather than a nice package.

Can't recall what the stickers were on my Enterprise, but I would likely have got it around that time too, so it's possible it was an early one, though debatable since I no longer have it :)

That's some thick traces there then!

Shame the vid wasn't a help, but that's the way if goes sometimes, and hopefully the vid was at least interesting :)

Yeah, Trafalgar watches were definitely the premium brand at the time, but disappeared as soon as the cheap LCD watches flooded the market in 77/78.They were selling for more than £25, which was a lot of money in '76.

Due to the batteries lasting only about a month I went back to my Timex wind-up watch pretty quickly. I got my first LCD watch from Cardigan market in '78 for, I think, £6.

stephen_usher wrote: 01 Jan 2024 15:18 Yeah, Trafalgar watches were definitely the premium brand at the time, but disappeared as soon as the cheap LCD watches flooded the market in 77/78.They were selling for more than £25, which was a lot of money in '76.

Due to the batteries lasting only about a month I went back to my Timex wind-up watch pretty quickly. I got my first LCD watch from Cardigan market in '78 for, I think, £6.

Can't recall my first digital watch, I mostly used a wind up Timex too, and it would have been about the same time period. My second wind up watch was a Sekonda, which I may still have somewhere. I kind of recall having a red LED watch, but it was never very good, and you had press a button to get the time.

These days I have analog type watches with supporting LCD displays, though my eyes are getting a bit small to see the tiny letters on the LCDs!!!

The OPD has become more and more flaky recently with it starting with 5 bars on the left and stopping.

This evening I thought I'd take a look as the machine wouldn't start up. Seeing as 4 bars was caused by a bad ROM I tried removing each ROM in turn. After changing one it booted, but then stopped, so I reseated it again but nothing changed. So, then I tested the data bus, all looked fine. Checked the ZX8302 and looked fine. Then I touched the ZX8301 chip and things changed.

I always thought that the soldering on that chip looked iffy as many pins look as if they have almost no solder. Gently pulling on one end of the chip allowed the machine to boot.

I'm going to reflow all the pins I think.

I'm always in a time-tunnel when I read this kind of stories.

You even mention stuff that was hidden deep in my memories and that I have completely forgot, and it suddenly arises from the past...

8-)

Spot the solder...

stephen_usher wrote: 03 Jan 2024 08:00 Spot the solder...


IMG_3529.jpeg

Makes me wonder if the IC has been reworked/replaced (Badly!) before.

Whatever happened, it's pretty terrible soldering, but hopefully a relatively easy rework.

I took the motherboard out of the case and it has been reworked and the chip replaced "in antiquity", so that ULA had obviously died in the past.

stephen_usher wrote: 03 Jan 2024 18:26 I took the motherboard out of the case and it has been reworked and the chip replaced "in antiquity", so that ULA had obviously died in the past.

Not reworked very well then!

Well, I've reflowed but with difficulty.

Even with ChipQik flux the solder isn't flowing up the chip legs very well, which is probably why the original repair didn't work well.

Anyway, it didn't actually help with the fault.

The symptoms are that if it starts with 5 bars I can leave the machine for n minutes (where n can be ten) and then the relay will click. Once this happens I can turn the machine off and on again and it'll boot normally and *usually* continue to work.

I wish I knew what the bars meant. I'm sure that they're a diagnostic.

P.S. Found a manual on-line with a fault-finding chart... Helpfully it says, "Fewer than 11 lines on screen ---Yes---> Replace motherboard"