Posted By
MMS
on 2019-04-06
05:02:10
 |  Re: what are the odds of massive failure of plus 4
Maybe a little hypothetic/OFF point
The whole story reminds me to our ESD experience at Philips.
When we started to produce DVD players and CD recorders, the office persons did not care about ESD.
I mean, there were some precautions (the intrernal wrapfoils were ESD free or condustor, including the boxes, we had humidity control, etc), but the personal protection (coats, ESD bracelets, etc) was used exclusively by the repairmen and assembly persons on production lines. And there was no tight control, if properly used. Especially low educated workers tend break the rules and cheat us.
So after 1-2 years the laser diodes of the CD and DVD drives started to weaken and die on the market, so we got a very detailed training how ESD works, so all the engineer and management staff had to wear all the ESD protection TOGETHER. It is not required to even touch the PCB to kill it, if you are charged enough in your pullover, it is enough to get close enough to a PCB on a desk to kill it. Not immediately, it is a slow agony for the ICs. The more you use, the earlier it shows the effect. It may take years to show the results...
The ESD taken very seriously, even an engiunner could get a warning going next to the production line without proper protection (ESD coat, etc). Then this kind on died ICs and laser diodes disappeared on the market, and our Field Call Rate dropped by almost 2%. This is a lot, if you translate it into warranty cost.
I agree, that the overcurrent protection-free TED did not help too much, and the 8501 us rather hot at 2.2MHz. On the other hand (based on my personal experience) I am not 100% confident, that all the ESD rules are ALWAYS kept at the different production lines (these machines were produced in Germany, UK, but also Far-East AFAIK). My experinece is from the early 2000. So you may imagine how much they may know at the mid 80s (not at the IC factories, but at final assembly lines)
It may happen, that these ICs were also sensitive to ESD, but much more resistant than a laser diode. So it may take 5-10 years of operation to die... Then we cannot do to much, just to swap them to modern equivalent ones.
To prove it, it would be interesting to see the defect ratio of the different production factories, and WHERE the currently working ones made. Please do not forget, that C= planned working machines only with 2-3 years lifetime, and C= always tried to save pennies everywhere. ESD protection costs a LOT, so if they chose a cheap location, probably there could be "issues" or loose control on that point.
But it is just a hypothesis.
About upgrades:
256KB extension diagram seems not so complex, but it requires internal wiring and soldering AFAIK. I am not brave enough to endanger the "life" of my only living Plus/4 :-)
Actually there is a not documented pin on the Expansion port say N/C, while on an early diagram is says Ram Enable. I put this question to Bil on FB, if the Plus/4 external RAM expansion was really planed or not, but got no answer.
Till the external RAM expansion is not possible, for me it is a NoGo solution. If an external one could be developed, I am in to buy one.
There are some SWs using this 256KB RAM expansion (Solder/Csory/Hannes), but I think they could be more wide-spread if it could work as an external (online buyable) unit, worth to mention, that I would recommend external (eg USB based) 5V Power source for that to do not overstress these old circuits.
I highly recommend SD-1541/II, it is a fantastic IEC unit with very high compatibility and a nice intuitive UI and control. It is developed in Hungary,and can be ordered from here. I saw several ones at Arok 2018, and I am not aware of any SW cannot be run from that, even the latest C64 demos ran perfectly.
http://retroemu.hu/sd1541-ii.php?lang=en
There was no aim to develop a new GFX card, because our TED chip is the best! If I put away the jokes, certainly HW sprites and chunky GFX modes would be great, but you know SID cards are also rather expensive, I am not sure, who would invest so much in such a small community?
There is one more challenge: there is no chance to produce expansion port expander/splitter, because of the very strange pin distance we have, you cannot buy that connector from anywhere. So you have an 1551, a SID Card, and maybe a GFX card, or a memory expansion, and you should choose, which one you prefer, as you cannot them all together.
Solder had a solution for that, he developed the external cards with C64 connector, and he developed an expansion port splitter with C64 type of socket (taking out the N/C pins) and it was easy to buy.
Two years ago I personally saw a highly upgraded Atari at Ha'vangarda in Poland, if had internal SD, RAM upgrade and an extreme GFX card (had original pokey sound card, eh :-) )
(Maybe it was owned by Hellboy? I am not sure). It was a very nice experience, but I think it is not the way this scene will do.
If you check, even less and less new release with "only SID music", or the original TED's SID FRQ emulation is also used. (because our machine is so capable :-) )
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