exxos's Atari, Amiga & retro forum

rubber_jonnie wrote: 26 Apr 2021 11:39 Are there any other ULAs I should know about?

Nope. Everything else is discrete logic and off the shelf ICs.

cmorley wrote: 27 Apr 2021 09:16

rubber_jonnie wrote: 26 Apr 2021 11:39 Are there any other ULAs I should know about?

Nope. Everything else is discrete logic and off the shelf ICs.

Brilliant, thank you:)

Interesting, I removed IC6, the ULA video processor, and cleaned the pins and socket and I now get a continuous beep and caps lock light on. I'm assuming blank screen too as those problems seem to go together.

I'll call that progress and start working my way through the next steps in the troubleshooting manual :)

That involves mostly removing ICs and cleaning the contacts!!

Also, it has a lot of the horrible single wipe sockets I really hate, but if I can get things going with those I can have a long term plan to replace any of the single wipe sockets later

Reviewing the PCB and photos, plus schematics and repair guide, I seem tobe short some ICs.

Missing ICs now ordered, I think next I'll give the PCB a good solid check over solder side since I now have some illuminating magnifying specs that my father in law gave me.

Also thinking I need to work up a list of replacement sockets because every socket is single wipe and I find them bloody unreliable. In the meantime I will give them a squirt with some contact cleaner.

Fingers crossed the ICs will arrive soon and we'll see if we get any difference.

Current status is:
Continuous tone from the speaker
No Video out
Caps lock LED illuminated.

rubber_jonnie wrote: 28 Apr 2021 13:24 Also thinking I need to work up a list of replacement sockets because every socket is single wipe and I find them bloody unreliable. In the meantime I will give them a squirt with some contact cleaner.

I don’t know Rj... I have to say sockets have caused me a lot more trouble than any Benefits I have derived from using them time to time. I would consider just soldering them in if there dip devices. With that fancy desoldering toll you have it shouldn’t be a big deal replacing a soldered in chip. I rarely run into a bad chip that doesn’t connect to an IO port. All this chip changing we see on the forum is mostly try this try that and not actual trouble shooting.

PaulJ wrote: 28 Apr 2021 14:11

rubber_jonnie wrote: 28 Apr 2021 13:24 Also thinking I need to work up a list of replacement sockets because every socket is single wipe and I find them bloody unreliable. In the meantime I will give them a squirt with some contact cleaner.

I don’t know Rj... I have to say sockets have caused me a lot more trouble than any Benefits I have derived from using them time to time. I would consider just soldering them in if there dip devices. With that fancy desoldering toll you have it shouldn’t be a big deal replacing a soldered in chip. I rarely run into a bad chip that doesn’t connect to an IO port. All this chip changing we see on the forum is mostly try this try that and not actual trouble shooting.

I think maybe you've misunderstood. I only want to replace existing sockets that are of the single wipe type with newer dual wipe sockets. I'm certainly not going to have a massive desolder session and fit sockets everywhere, that's not how I roll. There is no way I'd go for a big bang solution like that, but the current sockets have really bad oxidisation on the wipes and unless contact spray works, there is no way I can clean the contacts, not to mention tweaking them to get back their springiness.

I've had very few problems with double wipe sockets, which I generally only fit if I have to remove an IC, but all of the single wipe ones I've encountered from 80's machines have been just awful.

rubber_jonnie wrote: 28 Apr 2021 14:30
I think maybe you've misunderstood. I only want to replace existing sockets that are of the single wipe type with newer dual wipe sockets.

Hmm, don’t thinks so.. If there normal dips 8,14,16,20 pin chips socketing again stands a better chance of causing more trouble than good. It’s apparent the sockets have caused a lot of issues so far. I think you are suffering under a false impression that there is a perfect socket which we all know is a false premise. If you look at modern electronic devices you will be hard pressed to find any sockets.. increased reliability and more cost effective. I know Rj.. they are a lot harder to repair but that’s where were headed.

PaulJ wrote: 28 Apr 2021 14:58

rubber_jonnie wrote: 28 Apr 2021 14:30
I think maybe you've misunderstood. I only want to replace existing sockets that are of the single wipe type with newer dual wipe sockets.

Hmm, don’t thinks so.. If there normal dips 8,14,16,20 pin chips socketing again stands a better chance of causing more trouble than good. It’s apparent the sockets have caused a lot of issues so far. I think you are suffering under a false impression that there is a perfect socket which we all know is a false premise. If you look at modern electronic devices you will be hard pressed to find any sockets.. increased reliability and more cost effective. I know Rj.. they are a lot harder to repair but that’s where were headed.

Honestly, I've done a lot of ST and other repairs and sockets just don't cause me any problems, and they save me time if a component fails again, or I need to remove for troubleshooting.

Where I have run into issues is using turned pin sockets, I find them to be terribly unreliable, especially if you're plugging in previously desoldered chips.

Then the situation is that the chips that are already socketed were done so from the factory, and were poor quality, and given the fragility of the mainboard I really don't want to have to desolder chips again if I solder them in directly and subsequently find faults that necessitate desoldering again, because even with the gun it is possible to damage these boards.

I agree that having chips soldered in is by far and away the best way to run a machine, but from my personal point of view, sockets have never caused me any problems, especially the more modern double wipe type.

In fact my H4 is fully socketed, bar the surface mount and other discrete thru hole components and it runs just fine.

Ya I can get on board with your logic.. just not for me. I eliminate sockets every chance I get and I can't remember a case where I had to go back and remove a chip that used to have a socket. I've also been using the PLCC glue and mmu on the my h4's and H5s. I use as few sockets as necessary. The CPU and eprom are always socketed. When Exxos has a fully PLCC based H20 you will most likely need to retire your sockets. But anyway good luck with the restore... keep and eye on that pesky iron. :D

PaulJ wrote: 28 Apr 2021 16:39 Ya I can get on board with your logic.. just not for me. I eliminate sockets every chance I get and I can't remember a case where I had to go back and remove a chip that used to have a socket. I've also been using the PLCC glue and mmu on the my h4's and H5s. I use as few sockets as necessary. The CPU and eprom are always socketed. When Exxos has a fully PLCC based H20 you will most likely need to retire your sockets. But anyway good luck with the restore... keep and eye on that pesky iron. :D

Don't get me wrong, I understand your desire to eliminate sockets, any additional physical connection is a failure point. I'm not entirely sure why the BBC came with so many sockets from the factory (Well apart from the ROM spaces) unless there were high fail rates for some components. Thinking about it there are correlations between the troubleshooting guide and the socketed ICs, so that might be a thing.

Each of us have the ways that work for us I guess :)

I always have an eye open for that pesky iron!!! I'd like to know how many burns I've had over the years, I expect it's quite a lot!!!