exxos's Atari, Amiga & retro forum

PhilC wrote: 14 Oct 2023 16:14 I do like those old thinkpad, I’ve got one so used that the palm test has worn through to the plastic underneath but it still runs happily all day long. Nearly bought it for the cyber legends worst computer comp

This machine ran as my home firewall for ages, and the screen got progressively worse, but it was a work giveaway, just needed a hard drive, probably more than 10 years ago, and it's incredibly robust, so I can't complain. Internally it has a metal frame too, which helps.

Amazing that your palm rest has worn out, but these Lenovo/IBM Thinkpads do seem to take a licking and keep on ticking. Just trying to install Linux Mint on it, see how it copes :)

Nice repair, and for a bargain price !

:D

HigashiJun wrote: 15 Oct 2023 08:46 Nice repair, and for a bargain price !

:D

Thanks 😁

Well, that was annoying. I powered up the MSTE to do a few bits and bobs, and got a bit 10 error during the boot RAM check. OK, let's try YAART. Same thing.

So, popped the HDD cover off and ran up the diag cart and one out of the 4 SIMMs had gone bad on me :(

Luckily I had another set spare and ready to drop in so I swapped the whole lot out and all good again.

The joys of running old gear :)

I don't get why ram always fails. Though on the falcon the signals were really bad and I started to design a ram board with filtering.. but nobody would likely buy it because nobody understands how common ram failure is :roll:

exxos wrote: 17 Oct 2023 09:42 I don't get why ram always fails. Though on the falcon the signals were really bad and I started to design a ram board with filtering.. but nobody would likely buy it because nobody understands how common ram failure is :roll:

It's odd, it's been running fine, but I haven't used it in a while, so I can only assume one of the ICs on the SIMM failed when it was powered up.

Easy enough to find the faulty SIMM using the diag cart, but annoying nonetheless. What was more scary was the worry of breaking the latches that hold the SIMMs in place, but I managed OK and none broke.

My recent Spectrum boards had so much bad RAM it was ridiculous. I can see why the 4116's fail, as if the power circuit goes bad, you can get high voltages on the 12v side that will kill them, and I had a 50% fail rate (Same in the TRS-80 with 4116 RAM). But for the upper RAM, they don't use 12v, only 5v, but I still had a 40% fail rate for the upper RAM.

rubber_jonnie wrote: 17 Oct 2023 10:03 My recent Spectrum boards had so much bad RAM it was ridiculous. I can see why the 4116's fail, as if the power circuit goes bad, you can get high voltages on the 12v side that will kill them, and I had a 50% fail rate (Same in the TRS-80 with 4116 RAM). But for the upper RAM, they don't use 12v, only 5v, but I still had a 40% fail rate for the upper RAM.

Yeah voltage spikes on the PSU etc won't help. In case of the falcon, the signals have several volts on them. Sometimes it would work fine, others it would error until a bit eventually failed.

exxos wrote: 17 Oct 2023 10:27

rubber_jonnie wrote: 17 Oct 2023 10:03 My recent Spectrum boards had so much bad RAM it was ridiculous. I can see why the 4116's fail, as if the power circuit goes bad, you can get high voltages on the 12v side that will kill them, and I had a 50% fail rate (Same in the TRS-80 with 4116 RAM). But for the upper RAM, they don't use 12v, only 5v, but I still had a 40% fail rate for the upper RAM.

Yeah voltage spikes on the PSU etc won't help. In case of the falcon, the signals have several volts on them. Sometimes it would work fine, others it would error until a bit eventually failed.

Yeah, not good. On the Spectrum if the 12v circuit goes you can get 70v straight into the RAM.

rubber_jonnie wrote: 17 Oct 2023 11:05 Yeah, not good. On the Spectrum if the 12v circuit goes you can get 70v straight into the RAM.

Crowbar it ;)

exxos wrote: 17 Oct 2023 11:19

rubber_jonnie wrote: 17 Oct 2023 11:05 Yeah, not good. On the Spectrum if the 12v circuit goes you can get 70v straight into the RAM.

Crowbar it ;)

You'd think they might have considered it back in the day, but no.

I suppose it would definitely be a possible thing to do though and has the potential to save not only the RAM but also the LM1889 that also takes 12v.