Search found 114 matches

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Tue Mar 04, 2014 6:31 pm
Forum: General Discussion
Topic: Cumulus Issues
Replies: 358
Views: 221253

Re: Cumulus Issues

Can you try just for the test to put a 50ohm resistor in line on D2 and do the measurement again?
this doesn't work. The Oric then boot no more and the signal is worse.
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Tue Mar 04, 2014 1:09 am
Forum: General Discussion
Topic: Cumulus Issues
Replies: 358
Views: 221253

Re: Cumulus Issues

@peacer did you only change the ram in your oric? i looks like that the IC's IC20 and IC8 are also newer. Original are this chips 74LS257 but you have 74HCT257 which are newer and has different high and low level voltage.
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Mon Mar 03, 2014 11:27 pm
Forum: General Discussion
Topic: Cumulus Issues
Replies: 358
Views: 221253

Re: Cumulus Issues

here are two maybe interesting pictures from the d2 pin. Sometimes the high status is not 5V. Maybe this is a problem... don't know yet.
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Mon Mar 03, 2014 9:41 pm
Forum: General Discussion
Topic: Cumulus Issues
Replies: 358
Views: 221253

Re: Cumulus Issues

here is a data line... looks good to me. So what can we do with a resistor better?
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Mon Mar 03, 2014 4:05 pm
Forum: General Discussion
Topic: Cumulus Issues
Replies: 358
Views: 221253

Re: Cumulus Issues

But at least making a Cumulusbusbus should be fairly simple to make with R or C on all the lines to prevent the ripple effect.
i can try that.

On which line is on the original Microdisk the edititable resistor and what is the value of it?
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Mon Mar 03, 2014 2:17 pm
Forum: General Discussion
Topic: Cumulus Issues
Replies: 358
Views: 221253

Re: Cumulus Issues

just a thought:
could it be a problem with the cumulus when the clock in the oric is faster or slower?
by metadata
Mon Mar 03, 2014 2:04 pm
Forum: General Discussion
Topic: Cumulus Issues
Replies: 358
Views: 221253

Re: Cumulus Issues

However I hope Cumulus/Cumulusbus have connectors BERG that would power them directly from a PC power supply type for example No. I used a different connector. It is not pincompatible and the Cumulus use one pin for the reset. So no good idea to use a BERG connector. And most of the PC power suppli...
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Sun Mar 02, 2014 9:12 pm
Forum: General Discussion
Topic: Cumulus Issues
Replies: 358
Views: 221253

Re: Cumulus Issues

So the Oric is powered throught the expansion bus
no. the Cumulus is powered throught the expansion bus.
by metadata
Sun Mar 02, 2014 2:53 pm
Forum: General Discussion
Topic: Cumulus Issues
Replies: 358
Views: 221253

Re: Cumulus Issues

yes. 9V is better than 12V. The regulator then only must convert 4V to heat.
@peacer can you measure the voltage after the regulator? It must be 5V and stay there also if the regulator gets hot.
GND is the upper pin (beside the power connector) and +5 is the lower pin.
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Sat Mar 01, 2014 3:10 pm
Forum: General Discussion
Topic: Cumulus Issues
Replies: 358
Views: 221253

Re: Cumulus Issues

i burned a few eproms with rom 1.0 1.1 1.1b and test all of it with the cumulus. All runs fine. So it is not a thing with the roms that the cumulus not runs on all orics
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Sat Mar 01, 2014 12:18 am
Forum: General Discussion
Topic: Cumulus Issues
Replies: 358
Views: 221253

Re: Cumulus Issues

Chema wrote:Anyway, those oscilloscope readings still seem a bit far from a square waveform to me.
the clock is never a real square. For a 30 year's old computer it looks good. :)
The clock high time is only round about 4us.
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Wed Feb 26, 2014 11:58 pm
Forum: General Discussion
Topic: Cumulus Issues
Replies: 358
Views: 221253

Re: Cumulus Issues

This may sound stupid...
no... it is normal for a 30 years old computer. There are always issues with the capacitors after this long time. Luckly the Oric is not so sensitive to this problems but with the connected cumulus it is maybe. I have seen a lot of strange thing because of defect capacitors.
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Wed Feb 26, 2014 10:12 pm
Forum: General Discussion
Topic: Cumulus Issues
Replies: 358
Views: 221253

Re: Cumulus Issues

we are trying to find out if there is something wrong with the PHI 2 line.
by metadata
Wed Feb 26, 2014 9:58 pm
Forum: General Discussion
Topic: Cumulus Issues
Replies: 358
Views: 221253

Re: Cumulus Issues

PHI 2 on my oscilloscope: With and without Cumulus connected.
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Tue Feb 25, 2014 9:14 pm
Forum: General Discussion
Topic: Cumulus Issues
Replies: 358
Views: 221253

Re: Cumulus Issues

i bought a eprom eraser and a few eproms. Time to check this thing with the ROM and test diffenrent versions on diffenrent oric's.