Telestrat failure?

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Symoon
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Telestrat failure?

Post by Symoon » Wed May 01, 2019 7:36 pm

Hi,

I tested my Telestrats today (2 different ones), none is working anymore.
All I get with HYPER Basic and Telematic ROMs is this, for both:
IMG_1416b.jpg
No reaction from the drive. Each Telestrat has its own set of ROMs.
Both were working 12 years ago, one was even tested and fixed by NightBird.

Any idea anyone? Could it be a power problem?
Thanks!

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ibisum
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Re: Telestrat failure?

Post by ibisum » Wed May 01, 2019 7:53 pm

Damnit, I just tested my Telestrat too. And alas, it is also non-functioning.

So consider me following this thread very closely along with you. :(

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Re: Telestrat failure?

Post by Symoon » Wed May 01, 2019 8:07 pm

ibisum wrote:
Wed May 01, 2019 7:53 pm
Damnit, I just tested my Telestrat too. And alas, it is also non-functioning.
Ouch, what happens with yours? Same pitcure than above, or something else? (if anything!)

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ibisum
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Re: Telestrat failure?

Post by ibisum » Wed May 01, 2019 8:17 pm

Just junk on the screen - nothing like yours. Doesn't matter what I do, I can't get as clean a picture as your...

I'm going to try another power supply in the next few days, and I'll follow up - hopefully we can both get our Telestrats back in working order ..

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Re: Telestrat failure?

Post by Symoon » Wed May 01, 2019 8:24 pm

I'll sadly be away from my Telestrats for a few weeks. Actually I can't use them much, they're stored far from my main living/working place. That's why it took me a while to have an opportunity to plug them again :(

Edit:
ibisum wrote:
Wed May 01, 2019 8:17 pm
Just junk on the screen - nothing like yours. Doesn't matter what I do, I can't get as clean a picture as your...
Beware that the SCART cable for Telestrat is different from the Oric-1/Atmos one. This is very important, I was told you could fry your Telestrat using the wrong cable.
Does your drive seem to work?

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Re: Telestrat failure?

Post by ibisum » Wed May 01, 2019 8:43 pm

SCART: oh shit, this may be the issue. I tried using the SCART cable that was in my Atmos, which is the one built by RetroComputing and has been quite reliable in the past. I hope I didn't fry my Telestrat, damnit. (Haven't tried the drive..)

But, I will need a few days to return to debugging this, as I'm now away from my collection. Have you got any references for me on the differences between SCART for Atmos and Telestrat?

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Re: Telestrat failure?

Post by Symoon » Wed May 01, 2019 8:57 pm

ibisum wrote:
Wed May 01, 2019 8:43 pm
Have you got any references for me on the differences between SCART for Atmos and Telestrat?
Here:
http://andre.cheramy.net/trucs/peritel.htm
http://andre.cheramy.net/trucs/peritel1.pdf

It's in French but André is a reliable source.

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Re: Telestrat failure?

Post by Steve M » Fri May 17, 2019 1:36 pm

It looks similar to the Atmos/ Oric-1 boot screens that you get prior to he main screen. Typical failure to boot. Could be all sorts of things.
I'm not sure what sort of RAM is in the Telestrat but the other Orics are well known for faulty RAM.

Electronic equipment needs to be used to keep it working. If it's just sitting , it can fail. Keep your Orics running to keep them healthy !

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Re: Telestrat failure?

Post by Symoon » Sun Jun 16, 2019 9:26 am

One of my Telestrats and two power supplies were heavily tested by Nightbird yesterday.
Verdict: it's the Hyper-Basic ROM that is damaged. That means all the ones I tested were damaged.

So, apparently, Telestrat cartridges don't age well. Nightbird tells me they can get erased with time.
What I don't know, is if a more frequent use f them would keep them alive longer, or would have no effect on their death?

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Re: Telestrat failure?

Post by iss » Sun Jun 16, 2019 11:08 am

Symoon wrote:
Sun Jun 16, 2019 9:26 am
What I don't know, is if a more frequent use f them would keep them alive longer, or would have no effect on their death?
My opinion is that the frequently usage doesn't help to keep data intact in UV-EPROMs.
There is no such analogy with the "refresh" cycle in DRAM chips.

Additionally there is no clearly stated info how long is the data retention time of these chips - different sources claim 10-20-40 years (and even >200 years but for EEPROM's). For me it depends on thing like: is the "window" well covered with nontransparent sticker, is the chip inside of a box or it's on direct light exposure (sun or indoor fluorescent light).
Interesting fact is that spikes in power supply can also lead to random bit "switching".

The good thing is they can be reprogrammed, so our old machines will survive :).

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Re: Telestrat failure?

Post by Symoon » Sun Jun 16, 2019 5:32 pm

Thanks ISS. In my newbie mind, I thought electronic chips would last forever ;)

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Re: Telestrat failure?

Post by mikeb » Sun Jun 16, 2019 7:38 pm

Also UV-EPROMS (the ones with windows on) have varying voltage requirements. Not all programmers meet the spec and so the chip may not be fully programmed, which can lead to early failure. The data stored isn't digital/binary after all, but a level of analogue charge. It's only rendered binary by a comparator that reads out 0 or 1.

Example: Some chips require the main voltage rail to be raised to 5.3v on programming (as well as providing a 12/12.5v VPP voltage). To be really sure, the EPROM should be verified back at 5.3v and again at 4.8v, to ensure correct readback under all voltage conditions.

Example: Some programmers use "smart algorithms" to save time, instead of a 50ms programming pulse for every location, they use incremental 1ms pulses (on one location), reading back the data, until it sticks, then program once more at e.g. 50% of the cumulative pulse so far. It's faster, but is it reliable? No-one will know until 30 years from now :)

UVEPROMS can fade, which is why it's important to dump out any data in them, and preserve it elsewhere.

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