Cumulus Issues

[Dom]

Thanks for the link Chema.
however, we are in the strange oric world ...
This 8 roms Oric works well with the Cumulus, while the non modified Atmos does'nt ...



I agrree with you, it might be interresting to understand why the "normal" ATMOS do not work.
But the fact is that I'm not able to do that. I just remember a kind of formula like U=RI ? from the old school days
I think I will bring this ATMOS with me to the next CEO meeting. Perhaps CEO's Hardware experts, could help.

[Chema]

Ah, yes. Sorry I misunderstood.

[Dbug]

I guess the good thing is that we have at least now a large consistent baseline: The cumulus devices are almost identical (apart the two different display controllers), use the same components, built by the same person, and running the same code.

The only differences are on the Oric side; which is much better than trying to solve the equation with real floppy drives with different models of components, added wires here and there, etc...

[NightBird]

NightBird: You tested all of your oric with both cumulus?

Hi, - all units tested with Cumulus #1 and 9V 14.4VA PSU and
- all units tested with Cumulus #2 and 9V 9VA PSU.

[NightBird]

I guess the good thing is that we have at least now a large consistent baseline: The cumulus devices are almost identical (apart the two different display controllers), use the same components, built by the same person, and running the same code.

The only differences are on the Oric side; which is much better than trying to solve the equation with real floppy drives with different models of components, added wires here and there, etc...

I agree. please find below an update of my compatibility tab between my Oric units and Cumulus. For the unit #7, the main issue was a DRAM (ok for a standalone boot but nok with Cumulus). Need to put all DRAM on sockets, put a new set of DRAM (ok), then change one by one until to find the faulty DRAM (my LEAPER 10 tester said this 'faulty' DRAM is ok)...

Remark: my 30 years old ORIC PSU would not boot a standalone ORIC (not enough current). I replace the capacitor (4700uF/16V) and the 4 diodes (4 x 1N4007), and now it works with Cumulus

I have two other units with 'randomized characters on boot screen', I will do same test, to be continue...

[NightBird]

Oric unit #10 is now fixed. Same problem as #7: 1 DRAM changed:

cumulus_compatibility_update2.png (4.29 KiB) Viewed 14088 times

Remember: before DRAM change, unit worked fine in standalone mode...

Here are 2 pictures of boot screen before change, showing the 'randomized characters on boot screen':

Need to check the third unit (#8)... To be continue...

[peacer]

I guess the good thing is that we have at least now a large consistent baseline: The cumulus devices are almost identical (apart the two different display controllers), use the same components, built by the same person, and running the same code.

The only differences are on the Oric side; which is much better than trying to solve the equation with real floppy drives with different models of components, added wires here and there, etc...

I agree. please find below an update of my compatibility tab between my Oric units and Cumulus. For the unit #7, the main issue was a DRAM (ok for a standalone boot but nok with Cumulus). Need to put all DRAM on sockets, put a new set of DRAM (ok), then change one by one until to find the faulty DRAM (my LEAPER 10 tester said this 'faulty' DRAM is ok)...

Remark: my 30 years old ORIC PSU would not boot a standalone ORIC (not enough current). I replace the capacitor (4700uF/16V) and the 4 diodes (4 x 1N4007), and now it works with Cumulus

I have two other units with 'randomized characters on boot screen', I will do same test, to be continue...

My PSU is giving 12 V and over 12 VA, not 9 V. it runs Oric and microdisc drive at the same time well. But as you know Cumulus doesn't work..

Does anyone has idea why my Oric works with 12 V, Not 9 V ? I know that, we have tried with adjustable PSU and 9V was not enough.

I am still worrying if failure of my cumulus is due to PSU or not but, without cumulus attached, Oric and microdisc drive works perfectly with this PSU .

About DRAM, I can tell you that, my rams were changed few years ago. Maybe that is the problem..

P.S. My display becomes exactly the same as this when cumulus is attached.

[ibisum]

So, I had this problem with my beta Cumulus, which was similar to yours, where I got different 'kinds' of system corruption depending on the power supply I used. I finally settled on one providing only 12V, 1.5A, and not a 'configurable' PS (like, with a voltage selector). I tried multiples of those, too. The point is not 1.5A/configurable, though: try as many different power supplies as you can, and maybe you will find one with the right/least amount of noise, perhaps?

I confess to not having a working scope, or I'd dive deeper into these variant supplies, but maybe its just a missing resistor somewhere, lol, and I have no idea how to find that.

[Chema]

This DRAM thing is quite interesting... Maybe at least we found one source of problems? are the specs of those DRAMs different from original Oric RAM chips?

On the 12V PSU, I'm no expert in this field, but as far as I know the voltage regulator inside the Oric will convert everything above 5V in heat. You cannot use 5V directly, but I think 7.5V should be enough. 9V might even be quite a lot, creating heat problems. Not sure if plugging 12V is a good idea.

As I said before I am using an Spectrum+ PSU (9v, 1.5 A) with the polarity reversed and it works perfectly with my standalone Oric, with my Microdisc Clone, and with my Cumulus.

[NightBird]

This DRAM thing is quite interesting... Maybe at least we found one source of problems? are the specs of those DRAMs different from original Oric RAM chips?

What are these specs (I do not know exactly: 4164-150 ns?).

On the 12V PSU, I'm no expert in this field, but as far as I know the voltage regulator inside the Oric will convert everything above 5V in heat. You cannot use 5V directly, but I think 7.5V should be enough. 9V might even be quite a lot, creating heat problems. Not sure if plugging 12V is a good idea.

Right, here are 2 pictures after changing, on original PSU - 9V 6.75VA - old capacitor and diodes with new parts (same values: 4700 µF 16 V and 4 x 1N4007),

and now it works well with Cumulus, measured current = 850 mA, not heat problem.

[Chema]

Just as a side note. Remember I had problems when booting Sedoric the first times (even the cumulus itself seemed to hang) then, after reset everything started working perfectly forth wrest of the session? Well, I tried today with the Amplibus attached and those problems are gone. Or they seem to.

My amplibus came with Silicebit's Microdisc clone. So it may be a good idea to connect Cumulus through an amplibus if you have one. No idea why.

[Chema]

What are these specs (I do not know exactly: 4164-150 ns?).

I think so. My memory chips are labeled M3764-RS15 from Oki, which I think are 4164-150 ns indeed. Anyway I know very little about these things. Attracting the attention from an expert in the field would be nice...

[NightBird]

About DRAM, I can tell you that, my rams were changed few years ago. Maybe that is the problem..

Hi, found a very interesting thing tonight. Perhaps it can solve your problem.

My third unit is fixed:

cumulus_compatibility_update3.png (9.95 KiB) Viewed 14023 times

Yet another DRAM changed, but I noticed on the 2 previous repairs, that the problem was fixed when I changed the last DRAM : IC12. So, tonight, I decided to change only IC12 on the 3rd unit. And it works!
Only chance? I do not think so, because IC12 is D7 (bit 7), and D7 is a little bit special on Microdisc. This line can be driven, and maybe the Cumulus is 'more severe' than Microdisc (Cumulus schematic quickly examined but did not saw a specific problem).

So, peacer, try to change only IC12 with other DRAM... Maybe...

Now I will test different DRAM trademark to establish a 'compatibiliy' list... Try to understand... To be continue!

[peacer]

Now the problem is, where can I find one DRAM ?

[Godzil]

Just as a side note. Remember I had problems when booting Sedoric the first times (even the cumulus itself seemed to hang) then, after reset everything started working perfectly forth wrest of the session? Well, I tried today with the Amplibus attached and those problems are gone. Or they seem to.

My amplibus came with Silicebit's Microdisc clone. So it may be a good idea to connect Cumulus through an amplibus if you have one. No idea why.

Be careful, the Cumulubus is an Amplibus, or some sort, and connecting two in a row may cause other problem (as it will add more delay on each lines)

It may work on some Oric, but also could cause problem on other..