Empathy List Archives

OE

Orin Eman

Thu, Dec 18, 2014 11:10 PM

#151518774079

Currently at $49.95 plus shipping.

It's showing a ROM error (7.7) on startup. I asked what the error was this
morning and they posted pictures this afternoon. It could be a candidate
for one of John Seamons' 5370 processor replacement boards assuming nothing
else is wrong.

I have the minimum bid in, but if anyone else wants it, go for it; I
already have one.

Orin.

#151518774079 Currently at $49.95 plus shipping. It's showing a ROM error (7.7) on startup. I asked what the error was this morning and they posted pictures this afternoon. It could be a candidate for one of John Seamons' 5370 processor replacement boards assuming nothing else is wrong. I have the minimum bid in, but if anyone else wants it, go for it; I already have one. Orin.

BC

Bob Camp

Fri, Dec 19, 2014 1:50 PM

Hi

A lot of errors on the 5370’s (A or B) can be traced to a couple of fairly simple issues:

Connectors and sockets. Simple un-plug and plug back in may solve the problem (at least for a while).
The power supply. The parts are pretty common, so it’s a fairly easy fix.
Alignment. This takes a while, but these beasts do drift.

No I’m not suggesting that you buy every single 5370 based on it being an “easy fix”. I would indeed check 1 and 2 above on any 5370 that comes in. There are things like ROM’s with known defects that die and are a bit more problematic to replace ( = get the replacement CPU board).

Bob

On Dec 18, 2014, at 6:10 PM, Orin Eman orin.eman@gmail.com wrote:

#151518774079

Currently at $49.95 plus shipping.

It's showing a ROM error (7.7) on startup. I asked what the error was this
morning and they posted pictures this afternoon. It could be a candidate
for one of John Seamons' 5370 processor replacement boards assuming nothing
else is wrong.

I have the minimum bid in, but if anyone else wants it, go for it; I
already have one.

Orin.

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To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Hi A *lot* of errors on the 5370’s (A or B) can be traced to a couple of fairly simple issues: 1) Connectors and sockets. Simple un-plug and plug back in may solve the problem (at least for a while). 2) The power supply. The parts are pretty common, so it’s a fairly easy fix. 3) Alignment. This takes a while, but these beasts do drift. No I’m not suggesting that you buy every single 5370 based on it being an “easy fix”. I would indeed check 1 and 2 above on any 5370 that comes in. There are things like ROM’s with known defects that die and are a bit more problematic to replace ( = get the replacement CPU board). Bob > On Dec 18, 2014, at 6:10 PM, Orin Eman <orin.eman@gmail.com> wrote: > > #151518774079 > > Currently at $49.95 plus shipping. > > It's showing a ROM error (7.7) on startup. I asked what the error was this > morning and they posted pictures this afternoon. It could be a candidate > for one of John Seamons' 5370 processor replacement boards assuming nothing > else is wrong. > > I have the minimum bid in, but if anyone else wants it, go for it; I > already have one. > > Orin. > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there.

PK

Poul-Henning Kamp

Fri, Dec 19, 2014 6:34 PM

In message 766218C3-5AC3-4189-899B-916858F1FF2C@n1k.org, Bob Camp writes:

A lot of errors on the 5370’s (A or B) can be traced to a couple

of fairly simple issues:

(E)PROMS loosing their memory.

--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.

-------- In message <766218C3-5AC3-4189-899B-916858F1FF2C@n1k.org>, Bob Camp writes: >A *lot* of errors on the 5370’s (A or B) can be traced to a couple of fairly simple issues: 4) (E)PROMS loosing their memory. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk@FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence.

GH

Gerhard Hoffmann

Fri, Dec 19, 2014 8:26 PM

Am 19.12.2014 um 19:34 schrieb Poul-Henning Kamp:

(E)PROMS loosing their memory.

Are the known good eprom images available somewhere? I would like
to refurbish my 5370A over the holidays. It still seems to work but has
at least some bad contacts in the backplane from time to time.

best regards, Gerhard

Am 19.12.2014 um 19:34 schrieb Poul-Henning Kamp: > 4) (E)PROMS loosing their memory. Are the known good eprom images available somewhere? I would like to refurbish my 5370A over the holidays. It still seems to work but has at least some bad contacts in the backplane from time to time. best regards, Gerhard

YO

Yuri Ostry

Sat, Dec 20, 2014 1:29 AM

Hello,

Friday, December 19, 2014, 21:34:35, Poul-Henning Kamp wrote:

PH> --------
PH> In message 766218C3-5AC3-4189-899B-916858F1FF2C@n1k.org, Bob Camp writes:

A lot of errors on the 5370’s (A or B) can be traced to a couple

PH> of fairly simple issues:

PH> 4) (E)PROMS loosing their memory.

Sometimes it is possible to "extract" original contents from "leaked"
EPROMs (and some parallel 28-series EEPROMS) by reading at reduced
Vcc. I done this several times with old test gear (Marconi 2955
sitting on my workbench had "leaked" calibration data in EEPROM,
for exapmle, and it was recovered successfully).

Erased cell reads as logical "one", programmed as log. "0". So, with
time, some programmed bits in "weak" cells revert to "1".

Usually I read chip at 5V a number of times, and save data in separate files,
then gradually decrease Vcc in 0.1V steps and continue to save
everything. Usually at some point there is no more new "zeros"
appearing, and comparing EPROM against readed data multiple times does
not produce any difference. If so, it is relatively good chance that
we have in buffer the same data that was originally programmed. Data
is programmed to a new chip, and old one saved for reference to return
to it if something going wrong.

If it is impossible to find "stable reading" voltage (for example for
older NMOS EPROMs that give up at 4.5V or so), it is still possible to
statistically find "unstable" bytes, processing a batch of files
readed at different voltages and from heated and cooled chip, but
result is much less reliable.

I understand, that it is always better to have a backup or to find
correct image from another unit, but sometimes EPROMs contain factory
calibration data, and you have to extract all that possible from
original chips.

--
Best regards,
Yuri mailto:yuri@ostry.ru

Hello, Friday, December 19, 2014, 21:34:35, Poul-Henning Kamp wrote: PH> -------- PH> In message <766218C3-5AC3-4189-899B-916858F1FF2C@n1k.org>, Bob Camp writes: >>A *lot* of errors on the 5370’s (A or B) can be traced to a couple PH> of fairly simple issues: PH> 4) (E)PROMS loosing their memory. Sometimes it is possible to "extract" original contents from "leaked" EPROMs (and some parallel 28-series EEPROMS) by reading at reduced Vcc. I done this several times with old test gear (Marconi 2955 sitting on my workbench had "leaked" calibration data in EEPROM, for exapmle, and it was recovered successfully). Erased cell reads as logical "one", programmed as log. "0". So, with time, some programmed bits in "weak" cells revert to "1". Usually I read chip at 5V a number of times, and save data in separate files, then gradually decrease Vcc in 0.1V steps and continue to save everything. Usually at some point there is no more new "zeros" appearing, and comparing EPROM against readed data multiple times does not produce any difference. If so, it is relatively good chance that we have in buffer the same data that was originally programmed. Data is programmed to a new chip, and old one saved for reference to return to it if something going wrong. If it is impossible to find "stable reading" voltage (for example for older NMOS EPROMs that give up at 4.5V or so), it is still possible to statistically find "unstable" bytes, processing a batch of files readed at different voltages and from heated and cooled chip, but result is much less reliable. I understand, that it is always better to have a backup or to find correct image from another unit, but sometimes EPROMs contain factory calibration data, and you have to extract all that possible from original chips. -- Best regards, Yuri mailto:yuri@ostry.ru

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