Need help fixing Oric 1

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cslee_work
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Need help fixing Oric 1

Post by cslee_work »

Hello, I'm new here but have owned an oric 1 since 1983. I am trying to fix mine. It was dead. It won't boot, I bypassed the regulator, fed in 5V directly. I connected the RGBS to one of these ( www.amazon.com/gp/product/B01MTKPWBW/re ... UTF8&psc=1 ) via the RGBS input and output of it to a VGA monitor.
After changing the DRAM mux and an attiny85 to hold the reset for 2 seconds, I can get the machine to boot. I see the boot up screen and the cursor prompt. However, after about 5 seconds the screen goes black, the BLEE module says there's "No Signal". At this stage, the keyboard works, I can hear clicks and ZAP works.
The only way to get the screen back is to power cycle. It is consistently going black after 5 seconds form boot-up. I hope someone can help me.
I scoped the RGBS and the signals do not drop out when the screen goes black.

Hope someone can help as I have an Erebus coming in a few weeks.

thanks,

Chin

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Dbug
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Re: Need help fixing Oric 1

Post by Dbug »

(I split your post to a new topic, avoid reusing topics because it just makes it harder to follow up on issues.)

I'm not a hardware guru so I will not provide any help in that :)

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Chema
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Re: Need help fixing Oric 1

Post by Chema »

Not a hardware guy, either, so better wait for someone more experienced to answer, but I'd say that if the Oric boots and works fine for 5 seconds(every time), then the screen goes black but it still produce keyclicks and sounds, I'll bet for a problem or incompatibility with the converter module (RGB to VGA).

I'd try to check with a TV first, maybe using the RF modulator output or a proper RGB to SCART cable.

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kenneth
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Re: Need help fixing Oric 1

Post by kenneth »

I m agree with Chema, the RF output with the aerial cable is the best way to check your Oric.
NB: With Erebus, your Oric-1 will become an Atmos.

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mikeb
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Re: Need help fixing Oric 1

Post by mikeb »

I also suspect that converter may be looking at the signal from Oric and disputing that it is a valid video signal :)

For a TV set/monitor of the era, close enough was good enough. All these modern smart devices are more likely to pick holes in the signal!

Is there any configuring possible of the converter module to make it not screen blank/more tolerant?

Also, instead of powering Oric off, wouldn't just disconnecting the RGBS cable and reconnecting it cause the adapter to wake up and give you 5 more seconds? To the adapter, how would it know that you've powered Oric off (other than just a loss of video signal)?

cslee_work
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Re: Need help fixing Oric 1

Post by cslee_work »

Hi, I've looked at all the settings in the menu and nothing helps. I agree, disconnecting the RGBS should recover the signal but it does not.
I'm going to put in the debug rom (I have to program one first). Also, before it booted up (i.e. before fixing the mix), I used to get the 3 white bars. That's doesn't go blank after 5 seconds.

However, I no longer have a PAL RF TV as I now live in US.

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Dbug
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Re: Need help fixing Oric 1

Post by Dbug »

What type of SCART cable are you using?

I know that my video converter did not like the old cable and power brick I had, but after I replaced it with a new self-powered cable from Retrocomputer Shack, I got much more success with the display.

cslee_work
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Re: Need help fixing Oric 1

Post by cslee_work »

Dbug,
What kind of issue you are having with the display? I'll put a bench power supply to on it to check.

thanks,
Chin

cslee_work
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Re: Need help fixing Oric 1

Post by cslee_work »

kenneth wrote:
Tue Jun 30, 2020 1:50 pm
I m agree with Chema, the RF output with the aerial cable is the best way to check your Oric.
NB: With Erebus, your Oric-1 will become an Atmos.
Kenneth,
What do you mean by "With Erebus, your Oric-1 will become an Atmos"? Does the erebus replaces the ROM on board the ORIC ?

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Dbug
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Re: Need help fixing Oric 1

Post by Dbug »

cslee_work wrote:
Tue Jun 30, 2020 6:56 pm
What kind of issue you are having with the display? I'll put a bench power supply to on it to check.
It was mostly a case of SCART cables having very approximative connections, not everything wired, or not the right values for the resistors, or having the power brick not deliver the right voltage for the SCART selection circuit, some TV's did not connect to the Oric at all, some other would lose the sync (scrolling picture over the screen), etc...

cslee_work
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Re: Need help fixing Oric 1

Post by cslee_work »

Hi all,
I'm going to burn the debug ROM into a AT28C256-15PC which is a 32K device. I think if I'm not mistaken, I need to concatenate the binary to fit the space. Is that true, if so can some one tell me how to concatenate it? in windows that is.

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kenneth
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Re: Need help fixing Oric 1

Post by kenneth »

cslee_work wrote:
Tue Jun 30, 2020 7:04 pm
kenneth wrote:
Tue Jun 30, 2020 1:50 pm
I m agree with Chema, the RF output with the aerial cable is the best way to check your Oric.
NB: With Erebus, your Oric-1 will become an Atmos.
Kenneth,
What do you mean by "With Erebus, your Oric-1 will become an Atmos"? Does the erebus replaces the ROM on board the ORIC ?
Exactly :wink:

cslee_work
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Re: Need help fixing Oric 1

Post by cslee_work »

Dbug,
I was not using a SCART but just the harness that came with the BLEE adapter and I wired it to a 5-pin DIN plug. Since I got 5 seconds of video, I concluded it is wired correctly.

thanks,

Chin

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iss
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Re: Need help fixing Oric 1

Post by iss »

cslee_work wrote:
Tue Jun 30, 2020 10:34 pm
I need to concatenate the binary to fit the space. Is that true, if so can some one tell me how to concatenate it? in windows that is.
Use command prompt and type:

Code: Select all

copy /b diag.rom + diag.rom diag32k.rom
In Oric pin1 is connected to VCC, so A14 will be always HIGH which means only the second half of the EPROM will be accessed i.e. the concatenation makes sense :).

Else, about the video output issue - Oric doesn't have any power saving capabilities :mrgreen: - check the BLEE!

cslee_work
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Re: Need help fixing Oric 1

Post by cslee_work »

iss wrote:
Tue Jun 30, 2020 11:28 pm
cslee_work wrote:
Tue Jun 30, 2020 10:34 pm
I need to concatenate the binary to fit the space. Is that true, if so can some one tell me how to concatenate it? in windows that is.
Use command prompt and type:

Code: Select all

copy /b diag.rom + diag.rom diag32k.rom
In Oric pin1 is connected to VCC, so A14 will be always HIGH which means only the second half of the EPROM will be accessed i.e. the concatenation makes sense :).

Else, about the video output issue - Oric doesn't have any power saving capabilities :mrgreen: - check the BLEE!

Thanks. So the debug ROM is padded to fit in exactly 16K.

I have to build the arduino EEPROM programmer first. Hope to get it soon. Will update when I have it.

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